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Archive for the ‘Host plant resistance’ Category

Lentil breeding advances set to continue

North Queensland Register

Gregor Heard

Gregor Heard@grheard20 Oct 2021, 3 p.m.Grains

Agriculture Victoria lentil breeder Arun Shunmugam with a promising line of yet to be commercially released lentils in a trial at the pulse trial site at Propodollah, near Nhill, last week.

 Agriculture Victoria lentil breeder Arun Shunmugam with a promising line of yet to be commercially released lentils in a trial at the pulse trial site at Propodollah, near Nhill, last week.Aa

IN A YEAR with many contenders for most lucrative crop lentils are making a solid charge.

Values are in excess of $1000 a tonne, primarily in light of a lack of product from the world’s largest exporter of the legume, Canada, and an easing of tariffs from the world’s largest importer, India.https://7d116f708d3262b63c59ece0b6732cc5.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html

RELATED: New field peas

It has farmers in the lentil belt through Victoria and South Australia excited about this year’s harvest, with a kind season in regions such as the Wimmera meaning many crops are displaying outstanding yield potential.

Given the buzz around the crop at present it is no wonder lentils were one of the major talking points at last week’s Southern Pulse Field Day near Nhill in Victoria’s Wimmera.

Agriculture Victoria pulse breeders Jason Brand and Arun Shunmugam said there were a number of promising new developments in the lentil breeding pipeline.

In particular two cultivars yet to be commercialised are performing well in trials, with Dr Brand saying there was huge yield potential in the two lines.

Dr Shunmugam said other focuses of breeders included looking to incorporate more frost resistant genetic material along with further advances in herbicide resistant and tolerant varieties.

The crowd at the Nhill field day said Clearfield / imi-tolerant lines such as Hallmark and Hurricane were popular as they gave flexibility within the rotation and reduced the plant-back risk when planted following another Clearfield line.

Dr Brand said frost and waterlogging tolerance remained two key objectives.

He said there was a complex interaction which meant plants just metres apart could fare vastly differently.

“You can see even in the trials here that some plants look like they’ve incurred frost damage and just a couple of metres away with slightly different soil type and slightly higher up they are unaffected.

“Some form of tolerance to both these stresses would be a great win for the industry,” Dr Brand said.

He said the breeding sector wanted feedback from growers about what herbicide tolerance traits were wanted.

“It is a complex one as we have to manage market expectations and maximum residue limits in with what is going to work well agronomically, but we’re really keen to hear what growers would be interested in seeing in future varieties,” he said.

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Development of blight-resistant potato is a staggering breakthrough

Agriland

Last week saw the launch of a new blight-resistant potato variety that is also resistant to many other diseases.

I believe this news must rank as one of the most important breakthroughs within the field of agricultural science in living memory.

What makes this development all the more memorable is the fact that it has been achieved without the use of genetic modification (GM) and/or genomic editing.

It truly was a case of plant breeders seeking out the native potato strains that they needed in Peru, and taking the project on from there.

Blight-resistant potato

In my opinion, the scale of this breakthrough is truly hard to quantify. Currently, blight-related losses within the international potato sector amount to €8.5 billion.

Meanwhile, the costs associated with the purchase of fungicides to treat the disease come in at a similar value.

So the end result of all this represents a ‘win-win’ scenario, both for growers and those who consume the humble spud.

For the record, one third of the world’s population still rely on potatoes as the main source of energy in their diets.

Commercial scale

The coming years will see if the claims made by the plant breeders for the new potato variety can be verified on a truly commercial scale in countries around the world.

One of the most significant aspects to the work undertaken, has been its total dependence on the plant biodiversity that exists in Peru.

If ever the world needed proof that we do away with native species and the vast diversity within the natural world that is all around us at our peril, this is it.

This plant breeding breakthrough also flies in the face of the likes of Monsanto, which seems to think that GM is the answer to all our problems.

In truth, I am fast coming to the conclusion that GM and all other related sciences could be creating long-term issues for humanity – many, or all of which, could prove very difficult to step back from.

It’s also worth pointing out that the development of the new variety completes the circle, where the humble potato is concerned.

The original tubers were brought into this country from South America almost five centuries ago.

So it is right and fitting that plant breeders went back to that part of the world to solve a problem that has been at the heart of world hunger for so many years.Also Read: Danish pig industry committed to improving maternal linesOPINIONPOTATOES

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Insight into the plant immune system

by American Phytopathological Society

New study provides insight into the plant immune system
Clear demarcation between lesioned and nonlesioned sectors in the chimeric Rp1-D21 plants. Credit: Shailesh Karre, Saet-Byul Kim, Bong-Suk Kim, Rajdeep S. Khangura, Shannon M. Sermons, Brian Dilkes, Guri Johal, and Peter Balint-Kurti

Found in almost every plant species, disease-resistance proteins (R proteins) are an important part of the plant immune system. Many R proteins trigger an extreme hypersensitive defense response when they recognize specific pathogens, which results in rapid host cell death in the area surrounding the pathogen infection. This recognition event can also trigger changes in gene expression and other physiological and biochemical responses. The combination of these responses can be very effective in fighting diseases.

To further explore this hypersensitive response, Shailesh Karre, Peter Balint-Kurti, and colleagues at Purdue University, North Carolina State University, and USDA Agricultural Research Service, generated chimeric maize leaves in which an auto-active R protein (Rp1-D21), which triggers a defense response without requiring a recognition event, was present in one part of the leaf and absent in the other.

“In these leaves we saw that cell death and chlorosis were present only in cells that carried the auto-active protein and that cells without the auto-active protein did not display these symptoms even if they directly bordered tissue that had the protein and were undergoing cell death,” explained Balint-Kurti.

They also looked at the expression of hypersensitive response-related genes in both cell types and found that, unlike cell death, certain genes that were induced by the hypersensitive response were also induced in bordering cells without the auto-active resistance protein. Ultimately, they found that Rp1-D21 is cell-autonomous in regards to cell death but not in regards to the hypersensitive response.

“This informs some efforts to genetically engineer plants with R proteins,” said Balint-Kurti. “For example, it tells us that, in some cases, it may not be sufficient to express R proteins only in certain parts of the plant.”


Explore furtherCorn spots: Study finds important genes in defense response


More information: Shailesh Karre et al, Maize Plants Chimeric for an Autoactive Resistance Gene Display a Cell-Autonomous Hypersensitive Response but Non–Cell Autonomous Defense Signaling, Molecular Plant-Microbe Interactions (2021). DOI: 10.1094/MPMI-04-20-0091-RJournal information:Molecular Plant-Microbe InteractionsProvided by American Phytopathological Society

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Ghana’s first GM crop will help country deal with protein deficiency challenges – CSIR Scientist

Participants at the stakeholders meeting

Senior Research Scientist at the CSIR Dr. Richard Ampadu – Ameyaw says Ghana’s first genetically modified crop – the pod borer resistant cowpea (beans), will help the country deal with protein deficiency challenges among the population.

Dr. Ampadu – Ameyaw who works with the Science and Technology Policy Research Institute of the Council for Scientific and Industrial Research (CSIR) says the variety will offer the country a lot of benefits when it is eventually approved for the benefit of farmers and consumers.

“In a lot of places, being able to buy fish or meat is a challenge… More beans will help ensure more proteins for the people,” he observed.

“If it is well managed and well farmed, it could help a lot of people move away from poverty,” he added.

Dr. Ampadu – Ameyaw who is also Country Coordinator of the Open Forum on Agricultural Biotechnology (OFAB), was speaking at a stakeholders meeting in Accra organized by Alliance for Science Ghana (AfS Ghana) on ongoing efforts by the CSIR to introduce the improved GM cowpea varieties in the country.

Scientists at the Savannah Agricultural Research Institute (SARI) of the CSIR have completed trials on the pest-resistant cowpea (beans) and will soon apply for environmental/commercial release of the GM variety. The GM crop is expected to help farmers dramatically reduce their use of pesticides on cowpea farms, while also enjoying better quality yields of this important staple food. Cowpea popularly called beans is a popular delicacy which people consume in their waakye, gorbe (rice and beans), among several diets.

A destructive pest known as maruca pod borer has been responsible for highly low yields of the protein rich cowpea crop, forcing farmers to spray their fields with pesticides for up to 8 times in the 12-week life cycle of the crop. But the GM cowpea resists the pest which can cause destruction to about 80% of all cowpeas on farmers’ fields. They are particularly devastating because they damage not only the flowers and the buds, but also destroy the pods, resulting in grain and yield loss.

The pod borer resistant cowpea (PBR cowpea) as it is called, helped farmers cut down pesticide use on their farms by up to 80% during field trials supervised by scientists from SARI. The resistance is the result of the introduction of a gene from a naturally occurring bacteria Bacillus thuringiensis that has the capacity to control the pest. The scientists are confident the variety will help ensure more residents in rural areas have access to more protein-rich beans to help avoid cases of kwashiorkor and other protein deficiency diseases in children across the country.

Executive member of Alliance for Science Ghana Joseph Opoku Gakpo called for increased education on the varieties to ensure members of the public better understand what it’s all about and the objective for its development.

He disclosed the National Biosafety Authority will invite public comments from the public when it receives a request from the CSIR scientists for its approval and urged members of the public to take interest and contribute to the discussions.

“These decisions will be made based on whatever the available scientific data is. But the National Biosafety Authority is obliged by law to invite public opinion and factor that in the decision it makes. So, let no one sit on the fence. Especially the scientific community, Make your voices heard, This country is for all of us and we all have every right to be part of the key decisions that will eventually shape our agricultural sector,” Mr. Gakpo told the meeting.

Collins Oppong, an agricultural officer with the Directorate of Agricultural Extension Services of the Ministry of Food and Agriculture urged the scientists working on the variety to avail themselves to the public for proper education on the improved variety.

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The story behind the 100% public GM bean reaching Brazilian plates

Daniel Norero | August 31, 2021

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Common bean. Credit: Portal Voz da Comunidade
Common bean. Credit: Portal Voz da Comunidade

This article or excerpt is included in the GLP’s daily curated selection of ideologically diverse news, opinion and analysis of biotechnology innovation.In some Brazilian supermarkets, it is already possible to buy a new genetically modified (GM) common bean, which bears the corresponding GM labeling as required by local regulations. Nothing about this event would be news, considering that Brazil is the second global power in the production of GM crops after the United States and has seen its stores full of products with GM labels. However, this new bean isn’t another of many GM corn and soybeans typically created by North American companies, but rather a 100% locally developed crop by scientists from a state-owned company in the Amazonian giant.

The journey for this new biotech bean to reach Brazilian markets was long and not free of obstacles. It began in the search for a solution to the troublesome Bean Golden Mosaic Virus (BGMV) that can wipe out more than half of a farmer’s bean plants. This pathogen is transmitted by the whitefly, and causes losses estimated at 300,000 tons per year, enough to feed 15 million people.

“BGMV is a serious problem in tomatoes, soybeans and other plants, but in beans it’s also transmitted by whiteflies in a persistent way. When the insect already acquires the virus, it begins to transmit it throughout its life,” says Francisco Aragão, senior researcher at the Brazilian Agricultural Research Corporation (EMBRAPA) and co-creator of the new Brazilian GM bean. “That is why it is difficult to develop a resistance strategy and it’s also known that if you have only one whitefly per plant, you can already have 100% infection.”

Dr. Francisco Aragao (right) and Dr. Josias Faria (left), “fathers” of the Brazilian GM bean. Photo taken in January 2020 in a GM bean field in the city of Río Verde, Goias state. Credit: Francisco Aragao.

Before the new GM bean, the only BGMV control methods were cultural management, biological control, and the use of pesticides to control the virus host -the whitefly- with little results. “The average application [of pesticides] in a season is 10 times, but there are producers who apply 20 times or more. Even with those apps it is still possible to lose everything on some occasions. And if there is soy nearby, it will be very difficult to control the whitefly population in your beans,” says Aragao.

“The prices of insecticides are very expensive and for small farmers it’s difficult to have to use it so many times. In Brazil we have a very large area -about 1.2 million acres- where it’s not recommended to plant beans due to the great loss probability”.Follow the latest news and policy debates on agricultural biotech and biomedicine? Subscribe to our newsletter.SIGN UP

Not just for COVID: RNA also protects crops

Since the 1960s, EMBRAPA researchers have searched for bean cultivars with natural resistance to BGMV throughout the Americas, but results were unsatisfactory. Once only cultivars with only partial resistance and not adapted to Brazilian conditions were identified, EMBRAPA decided to invest in modern biotechnology and GMOs.

“This started in the 90’s when we began to try, on the one hand, to transform beans, which is still one of the most difficult plants to be genetically transformed, and on the other, to study the virus and develop strategies to obtain resistant plants,” Aragao relates. Together with his colleague, Josias Faria, they tried some biotechnological strategies such as antisense RNA -expression of the complementary RNA strand of a gene- and lethal transdominance -expression of a mutated protein that is essential for virus replication-, unfortunately without results or only partial resistance.

“With RNA interference technology, we started in the early 2000s,” Aragao says about RNAi, a natural defense mechanism in plants that “silences genes” but that wasn’t yet fully understood then. Despite this, in the 90’s there had already been success with the Hawaiian papaya, where genetic modification through interfering RNA would save the island’s farmers from the papaya ringspot virus.

How does it work? You’ve probably read or seen a lot in the headlines of the last year about RNA vaccines for COVID-19. In this case, the modifying mechanism with interfering RNA isn’t very different, and it literally works as a “vaccine” for crops. Scientists inserted a DNA fragment of the virus into the nuclear genome of the plant, with the aim of making it produce small double-stranded RNA molecules -known as small interfering RNA or siRNA- that silence the viral rep gene, a key gene for the virus’s replication cycle. As a consequence, the virus is unable to express this gene, its viral replication is interrupted and plants become resistant to the virus. In simple terms, you get a plant “vaccinated” against BGMV.

So in the future, not only will we protect ourselves from pandemics with RNA vaccines, our food can also be protected from deadly viruses with this technology.

It should be noted that this “gene silencing” method is a plant natural mechanism. A normal bean plant that is infected will generate siRNAs later, but not in conditions or levels to deal with the pathogen. With genetic engineering, scientists anticipate and adapt this natural system so that it is triggered the moment the virus enters the plant and it defends itself effectively.

“Something we observe is that flies acquire the virus from plants, but the virus doesn’t replicate in the fly, but in plants… and so the flies acquire more and more viruses,” adds Aragao. “We also observe that when viruliferous flies are put on modified plants, the viral load decreases in the fly, since it releases the virus and has no place to absorb more.”

“It’s interesting and we observe that the same happens for neighboring -not modified- plants”, Aragao indicates, about a potential protector effect that modified beans would have on neighboring conventional crops. “We hope that farmers who produce conventional beans alongside GM bean farmers will also benefit.”

Comparison between an elite line of GM bean resistant to BGMV (right) with healthy leaves and pods, and its conventional counterpart (left) with marked roughness and chlorosis, as well as deformed pods caused by BGMV. Credit: Souza, 2018

From the laboratory to the field

In 2004 the Aragao and Farias team developed the first bean plant immune to BGMV with the siRNA strategy. From 24 modified lines in total, two were immune, and line “5.1” was finally selected–so named since it derives from experiment number 5. “Then we began to do the greenhouse trials, after field trials, the biosafety analyzes and we generated all the data needed to answer all the questions from the National Technical Commission for Biosafety (CTNBio)”, says Aragao.

Aragao and Faria’s team demonstrated that this new GM bean was safe for human consumption, nutritionally equivalent, and had no effects on the environment different than conventional beans. For example, off-target or epigenetic effects were ruled out, and it’s important to note that the inserted transgene doesn’t generate any new proteins, but only small RNAs, which are very unstable molecules and are degraded during food processing.

The collected information was presented to the CTNBio regulators in 2010, approving its commercial release in 2011, a historic milestone as it was developed entirely by a public entity and was the first GM bean in the world. However, why has it taken about a decade to hit the market since that approval?

“We still didn’t have commercial cultivars, and it hasn’t been possible to develop them before because -here in Brazil- all field trials require authorization and also, each field must be in a certified area,” says Aragao about the Brazilian regulatory system. “And for the data generation rules of a new variety, it must be considered that Brazil has five areas for the bean, and we must carry out trials in at least three zones, of each one of the areas, for two years.”

Due to the cumbersomeness of the certification system, EMBRAPA preferred to wait for the commercial release of line 5.1 and only then to breed it with local varieties and endow them with virus resistance. “After commercial approval, you can sow wherever you want and it’s very difficult to have approval for all areas and zones before commercial approval,” adds Aragao.Related article:  15 years after debuting GMO crops, Colombia’s switch has benefited farmers and environment

After more than 31 field trials analyzing agronomic performance, the first GM cultivars of a Pinto -or Carioca- variety suitable for commercial use had already been obtained in 2015. The average yield of the modified cultivar was almost 20% higher than conventional varieties, and in areas with a high incidence of the virus, the profitability of GM beans was 78% higher.

GM bean field in the city of Río Verde, Goias state, in January 2020. Credit: Francisco Aragao

A fascinating piece of information that should be highlighted is the absolute immunity the modified plants have demonstrated since event 5.1 was obtained. “The losses from BGMV are zero. Every year, since we started experimental planting and until the commercial one, we never observe a single plant with the virus, the plants are totally immune,” says Aragao. A strong contrast with the high level of losses in conventional beans that ranges from 40% to 100% of the plants, and the remaining grain is usually deformed or not suitable for sale.

“With this bean, the idea is to have a reduction in pesticide applications. Instead of doing 10 or even 25 applications, the idea is to only do 3 applications (for other pests). What we did was create something more sustainable and safer for consumers”.

Consumer perception and exports

The rules and regulations were not the only problem to be overcome. Since 2015 it had been time to evaluate the best strategy to bring the new GM Pinto bean, a variety that is planted on more than three million hectares and represents 70% of the beans consumed in the country, to Brazilian tables.

“We started to see how to launch it, because beans are not like soybeans, corn or cotton for us. First, it’s a plant that is there on our plate and is consumed every day. Second, it is much more than a staple food, it has a cultural value,” emphasizes Aragao. Since 2015 they had discussed how to conduct the commercial launch, which did not take place until  the second half of 2020, after the seeds multiplication for the first sale.

What has been the attitude of farmers and consumers? In the case of farmers, apparently a success. “The sale of seed has been 100%. The seed producers didn’t sell more because they didn’t have any more,” says Aragao with a laugh. Regarding consumers, it’s still too early to evaluate it, but considering that supermarkets have been selling many products with GMO labeling for years -because GM corn or soybeans derivatives- Aragao hopes that there will be no rejections with the new bean. “If you go to the street and do a survey asking people if they would eat GMOs, probably 40-60% will say no, but in the supermarket they buy it without any problem,” he emphasizes.

Pinto bean package with the new GM variety. It bears the GM label in a yellow triangle with a letter T inside, and below the text: “Product elaborated from GM beans”. Credit: ChileBio

The fact that the Pinto bean produced in Brazil is destined for exclusive local consumption -unlike other varieties- facilitated its commercial release. “We also have modified black beans [from event 5.1], but for now we decided not to launch to the market, since Brazil exports black beans. For example, we have feijoada that is exported canned, and we don’t want to have problems in other countries,” says Aragao.

Genetic editing and new developments

Aragao and his team continue to work on improvements for this Brazilian bean and are already integrating new gene editing technologies to give it greater drought tolerance, decrease phytates (anti-nutritional components), and bestow resistance to other important bean viruses, such as carlavirus.

He also mentions an interesting work carried out with a GMO approach in collaboration with the Instituto Tecnológico de Monterrey from México in 2016, managing to increase the level of folate (vitamins B9) 150 times, an essential nutrient in fetal development and whose deficiency in pregnant women generates babies with severe congenital problems.

Dr. Francisco Aragao with other GM crops developed under his leadership: A folate-biofortified lettuce (left) and a ricin-free castor bean (right). Credit: ISTOÉ/Embrapa

Other side projects that Aragao and his team are working on include GM lettuce and castor beans. “In lettuce we are working towards virus resistance and an increase in the folate level. We are running field trials and it’s practically ready, but we don’t have all the biosafety data yet. We want to achieve resistance to two very important viruses in lettuce -all over the world – and stack it together with the increase in folate in the same line.”

In castor bean, they seek to eliminate ricin, a highly toxic compound from seeds that makes its use in animal feed unfeasible. “Castor oil plant is a very interesting plant for semi-arid areas, it has a tremendous tolerance to drought and saline soils. The idea is to use a plant like this to obtain not only oil, but also a source of protein for animals,” says Aragao. “The cake that remains after oil extraction is used as fertilizer, but using it as protein for animals would be a much more noble and sustainable purpose.”

Local efforts and science denialism

Until now there has been no opposition from activists and NGOs against the commercial release of the new GM bean. “The anti-GMO groups here in Brazil are fighting against Argentine HB4 wheat, so at least they have forgotten about the bean,” says Aragao. The HB4 wheat he mentions is the first in the world to be approved for commercial release in the neighboring country, but it was conditional on import approval by Brazil, the largest buyer of Argentine wheat.

“Some of the anti-GMO (activists) now claim to be in favor of science for the COVID vaccine. Here we see an example of science denialism. They are deniers depending on the technology, and they don’t consider that some of the modern vaccines are GMOs. To claim that GMOs aren’t safe is simply science denialism. All the scientific data shows that they are safe,” remarks Aragao.

Another important point is that EMBRAPA’s GM bean dismantles the classic narrative against GMOs on the grounds of alleged monopolies or that it’s an exclusive technology of large companies and rich countries. “GM beans are important to show that this technology is not only for big farmers, since we have many small bean farmers in Brazil. Why only for soy, corn and cotton? Why only for large farmers?” asks Aragao.

“It is a technology that can be used for small farmers and to address local problems and crops. Large companies aren’t going to invest in sweet potatoes, cassava, beans or peanuts. They prefer to invest in crops of large areas that are grown in different countries. That is why developing countries have to make an investment in their own problems, and why not, with technologies like this one,” he concludes.

In Brazil, there is hope that this biotechnological solution, fruit of ingenuity and effort of the public sector of Brazil, will be an example to be followed by other Latin American, African and Asian countries. This GM bean approval is a preferrable alternative to walking the European path that has been hindering this technology for more than two decades. Following the Brazilian path shows how to develop local solutions to local problems.

Daniel Norero is a science communications consultant and fellow at the Cornell Alliance for Science. He studied biochemistry at the Catholic University of Chile. Follow him on Twitter @DanielNorero

The GLP featured this article to reflect the diversity of news, opinion and analysis. The viewpoint is the author’s own. The GLP’s goal is to stimulate constructive discourse on challenging science issues.

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GM/Biotech Crops Report – September 2021

1st September 2021

  • GM/Biotech Crops Monthly Reports (BELOW) form part of BCPC’s free three-tier Biotech Crops Info service.
  • This service also includes a weekly round-up of news from around the globe – see BCPC Newslink GM Crops section.
  • Plus – Free access database on over 300 GM/biotech products covering 23 crops in the global market visit BCPC’s GM/Biotech Crops Manual – Register here for free access.
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GM/Biotech Crops Monthly Report September 2021

GM Crops approved in Europe

The EU has approved seven new GM crops for food and feed use in the EU but has not approved them for cultivation. This therefore allows the import of the products of these crops which will be subject to very strict labelling requirements but the lack of approval for cultivation means that they cannot be grown there. Since we are no longer part of the EU, UK growers could grow them and export the produce to Europe if approved here. The crops have been added to the Biotech crop database and are listed below. We don’t grow cotton or soybeans but the maize is a possibility.
They have also renewed the approval of Ms8 x RF3 (oilseed rape with tolerance of glufosinate), TC1507 x NK603 (maize with Lepidopteran insect resistance and tolerance of glufosinate and glyphosate) and one unspecified carnation for cut flower use. Full story

The future is here

SwiftDetect is a company that runs a new service here in the UK. Wheat growers order an envelope on-line and then collect 10 leaves from their wheat crop and post them off to SwiftDetect. Once received it is macerated and analysed for live DNA of Septoria and the grower receives details of how much Septoria there is in the crop even before it is detectable to the naked eye. This allows an informed decision of whether to spray or not. They are beginning to offer detection of other diseases in wheat and in other crops and expect in the near future to be able to tell you what level of resistance is in your Septoria and therefore which fungicides will work and which will be less effective. Full Story.

Transgenic maize in Nigeria

Trials evaluating maize that is both insect resistant and drought-toerant have shown that it can produce yields of 9 t/ha whereas the best of the current conventional varieties could only achieve a yield of 3 t/ha. Rolling this out to commercial production would greatly reduce the risk of famine in Africa. Full Story

Tan-spot resistance in wheat

Kazakhstan is one of the main wheat-growing areas in Asia and has suffered epidemics of tan-spot in wheat crops since the 1980s. Now a study jointly conducted by the Institute of Plant Biology in Kazakhstan and the International Maize and Wheat Improvement Centre have identified genes that confer resistance to this disease. The next step is to splice it in to the commercial varieties grown there. Full Story

Fish genes in plants

Researchers in Japan have spliced genes from the Medaka fish in to Arabidopsis to make a plant that glows green in the presence of endocrine-disruptor chemicals. They are planning to use it to monitor river water for the presence of pesticides such as imidacloprid and fipronil. Since fipronil is not approved in the UK and imidacloprid is banned in the UK and Europe the market for this test might be quite limited but perhaps it can also detect other pollutants. Full Story

Table-top Covid-19 detector

MIT and Harvard have developed a table-top device that uses CRISPR technology to detect the presence of COVID-19 in saliva. The test gives a result as accurate as a PCR test within one hour, costs about $15 to build and can even distinguish between different strains of the virus. Full Story

Heat-tolerant crops

Crops are sensitive to heat and a rise of just 2°C can significantly reduce yields of some crops. Now a team from Kansas State University and the Baylor College of Medicine have identified and patented a gene that can protect the plants from damage caused by this temperature rise and thus retain optimum yields. Full Story

THE LATEST ADDITIONS TO THE  GM/BIOTECH DATABASE ARE:

The latest approvals of biotech crops to report this month:

•  GHB614 x LLCotton25 x MON1958 – cotton with Lepidopteran insect resistance and tolerance of glyphosate and glufosinate approved for food and feed use in the EU.
•  5307 – maize with multiple insect resistance approved for food and feed use in the EU.
•  MON87403 – maize with increased ear biomass approved for food and feed use in the EU.
•  4114 – maize with Coleopteran and Lepidopteran insect resistance and tolerance of glufosinate approved for food and feed use in the EU.
•  MON87411 – maize with Coleopteran insect resistance and tolerance of glyphosate approved for food and feed use in the EU.
•  Bt11 x MIR162 x TC1507 x GA21 – maize with Lepidopteran insect resistance and tolerance of glyphosate and glufosinate approved for food and feed use in the EU.
•  MON87751 – soybean with lepidopteran insect resistance approved for food and feed use in the EU.

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Discovery of mobile disease detectors in plants could boost crop resilience

by Hayley Dunning24 August 2021Microscope image of the plant sensor glowing within a plant cellview large

A study of how plants identify and react to invading pathogens using mobile disease detectors could help researchers breed disease-resistant crops.

Many important crop plants can be devastated by pathogens including bacteria, fungi and viruses. Knowing exactly how some plants respond could give researchers the information to breed crops with the best disease-fighting power or even design new and improved immune sensors in genetically modified plants.

Understanding exactly how plants sense and eliminate disease-causing agents could allow us to engineer genetic control strategies by improving their immune systems.Dr Cian Duggan

Plant cells contain immune sensors that detect the presence of specific proteins called effectors, which infectious microbes use to facilitate infection. These immune sensors, called NLRs, have previously been found in specific ‘compartments’ within the plant cell, such as the nucleus or membrane.

The new study identified the first-known ‘mobile’ NLR immune receptor that navigates to where the microbe is invading. The research, led by Imperial College London researchers, is published today in Proceedings of the National Academy of Sciences.

Lead author Dr Cian Duggan, from the Department of Life Sciences at Imperial, said: “The world’s farmers lose 20-40% of their crops each year to plant pests and diseases, even with chemical control strategies. Understanding exactly how plants sense and eliminate disease-causing agents could allow us to engineer genetic control strategies by improving their immune systems.”

Tracking the action

The team studied the fungus-like microbe Phytophthora infestans, which causes potato blight, the disease responsible for triggering the Irish potato famine. Normally, what goes on inside the plant cell when P. infestans invades is difficult to study, since the cell quickly responds by causing its own death, aiming to starve the pathogen of nutrients.

The researchers were able to create a variant of the NLR that did not immediately respond with cell death, but left the preceding parts of the immune response intact, allowing them to study the cell reactions with high-powered microscopy. They attached fluorescent markers to a group of NLRs and watched what happened.

When fungal-type pathogens like P. infestans invade, they form specialised infection structures by creating extensions of themselves that are accommodated in the plant’s cell. Around these extensions, the cells create an enigmatic membrane, called the extrahaustorial membrane (EHM).

The team found that one type of NLR gathers on the EHM, around where the pathogen releases its effector proteins. Since the EHM only forms once invasion has begun, these NLRs must have travelled to the location from one of the other compartments in the cell, showing they are not static and can move to sites of suspected infection.

Investigating disease resistance

After sensing the effectors from the pathogen, the team observed the NLRs changing their organisation again, forming ‘puncta’ – distinct bright spots that spread out to the cell periphery, as seen under a confocal microscope.

Based on previous work, the team think these bright spots are molecular machines called resistosomes, which gather on the plant cell’s plasma membrane and are known to purposely kill plant cells in order to starve and eliminate the invading parasite.

The team are now looking to study the mechanism in more detail, both to discover exactly how the NLRs move to the EHM, and how the relationship between receptor accumulation and release at the EHM contributes to disease resistance.

These further insights could help select plants with more natural resistance to breed more resilient crops species, and also could potentially allow researchers to design more potent NLRs, creating more disease-resistant crop varieties.

Dynamic localization of a helper NLR at the plant–pathogen interface underpins pathogen recognition’ by Cian Duggan et al. is published in Proceedings of the National Academy of Sciences.

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Tolerance to virulence phenotypes of Phytophthora capsici in pasilla pepper cultivars

Phytophthora capsici is the most important limiting factor in the production of chile pepper in Mexico. This pathogen presents virulence phenotypes capable of infecting diverse cultivars of this crop. The search and development of resistance in chile pepper is an excellent alternative for the management of P. capsici. The objective of this work was to evaluate the response of four pasilla pepper cultivars to infection with five virulence phenotypes of P. capsici. Pasilla pepper landraces PAS-1, PAS-2, PAS-3, and PAS-4 were inoculated with P. capsici isolates MX-1, MX-2, MX-7, MX-8, and MX-10. Two experiments were conducted under greenhouse conditions from April through June 2017 and April through June 2018. ‘California Wonder’ was included as a susceptible control, and uninoculated plants were included as a negative control. In each experiment, groups of six 56-day-old plants from each pepper cultivar were inoculated with each virulence phenotype. Disease severity was evaluated 20 days after inoculation using an individual plant severity scale. All pepper cultivars were classified as resistant = R, moderately resistant (MR), tolerant (T), moderately tolerant (MT), or susceptible (S), according to the frequency of resistant plants (severity 0–1). ‘California Wonder’ and ‘PAS-4’ were susceptible to all five virulence phenotypes. The rest had different responses to the virulence phenotypes, but ‘PAS-2’ and ‘PAS-3’ were susceptible to only one of the five virulence phenotypes. Pasilla peppers with low severity exhibited a slow rate of infection, which is a mechanism we have called “slow wilting.” The pasilla pepper cultivars PAS-1, PAS-2, and PAS-3 could be used in plant breeding programs as sources of genetic tolerance and moderate resistance against P. capsici.

Read the entire paper at journals.ashs.org

Publication date: Mon 30 Aug 2021

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New Technology Delivers Resistance Against Cercospora — The ‘No. 1 Production Problem’ In Sugarbeets

By Becca Roberts Last updated Aug 16, 2021

New technology delivers resistance against cercospora — the 'No. 1 production problem' in sugarbeets

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New sugarbeet seed varieties resistant to cercospora leaf spot disease were commercially available for growers to plant in southern North Dakota and Minnesota in 2021. The improved varieties will save tens of millions of dollars in spray and processing costs and could save hundreds of millions in crop losses.

Mohamed Khan, a professor and Extension sugarbeet specialist for the University of Minnesota and North Dakota State Unviersity, said he expects to see most farmers to adopt the technology in the next three years. He thinks its use in the next two or three years will extend to Michigan, Montana, Nebraska, Colorado and Wyoming.

Sugarbeets are the most prominent specialty crops from southern Minnesota to the Canadian border through the Red River Valley, accounting for some $5 billion in economic activity. But that activity can be hurt by cercospora, which turns green leaves brown, shutting down yield potential.

The new CR+ (cercospora resistance plus performance), from KWS Saat, parent company for Betaseed, commercialized seed for some growers in southern Red River Valley of North Dakota and into southern Minnesota.

This year’s sugar beet crop near Foxhome, Minn., shows potential for a healthy, 30-ton-per-acre yields, but Cercospora leaf spot can quickly cut yields, reduce sugar content from 18% sugar down to 15%, and increase the processing costs of removing impurities. Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

This year’s sugar beet crop near Foxhome, Minn., shows potential for a healthy, 30-ton-per-acre yields, but Cercospora leaf spot can quickly cut yields, reduce sugar content from 18% sugar down to 15%, and increase the processing costs of removing impurities. Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

German-based genetics company KWS Saat in its website on the topic says about two-thirds of global sugarbeet acreage has a moderate to high cercospora pressure. Cercospora is the most destructive leaf disease of sugarbeets, sometimes cutting crop yield by 50% in some places, the company says on its website.

Khan said the new technology will prolong the usefulness of other fungicide treatment.

“It’s a real game-changer,” he said, describing the technology in a private tour of his cercospora research plots near Foxhome, Minn., about an hour east of Fargo, N.D. The site has a plot tour on Aug. 24, 2021.

Khan manages research/demonstration plots annually of about 25 acres on land farmed by Kevin Etzler of Foxhome. The research is open to the public, usually replicated four times, on a scale similar to typical farm fields. Here, the Minn-Dak Farmers Cooperative of Wahpeton, N.D., and American Crystal Sugar Co., of Moorhead, Minn., evaluate (blind-)“coded” varieties they test for various seed companies to ensure they meet minimum standards for cercospora vulnerability. Much is at stake.

Extension Service sugarbeet specialist Mohammed Khan supervises inoculation and other studies at sugar beet research plots at Foxhome, Minn., helping to evaluate new disease-resistant varieties and fungicide spray regimens. Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

Extension Service sugarbeet specialist Mohammed Khan supervises inoculation and other studies at sugar beet research plots at Foxhome, Minn., helping to evaluate new disease-resistant varieties and fungicide spray regimens. Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

Infested fields hit can easily lose 40% of their yield and about 2 to 3 percentage points of sugar — a loss of millions of pounds of sugar and millions of dollars throughout the growing regions.

“You can easily lose $300, $400, $500 per acre,” Khan said.

A primer on the history of cercospora

South to north

University researchers at Foxhome, Minn., test plots inoculate varieties to help study disease resistance and effectiveness of fungicide combinations. Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

University researchers at Foxhome, Minn., test plots inoculate varieties to help study disease resistance and effectiveness of fungicide combinations. Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

Since 2016 in the Minnesota/North Dakota region, cercospora has been most prevalent in the two southern co-ops: Minn-Dak Farmers Cooperative and Southern Minnesota Beet Sugar Cooperative. The areas where those co-ops operate generally get more rainfall and heat, which increases yields but also creates more problems with cercospora. Over the past two decades, sugarbeet yields have increased nearly 50%.

Beets are a high investment crop in the three closed cooperatives. Farmers in North Dakota and Minnesota together produce 650,000 acres of beets. Diseased plants can produce 1 trillion spores per acre.

“That’s trillions and trillions of spores are circulating. The larger the number of spores, the more mutations that can lead to fungicide resistance,” Khan said. “We are trying to kill the fungus and the fungus wants to live.”

From 2000 to 2015, farmers got excellent control by applying two to four fungicide applications per year, depending on the farms’ locations.

One fungicide type is the “quinone outside inhibitors” (“QoI”), a fungicide that specifically stops the production of energy. The main QoI for sugarbeets has been “Headline,” a pyraclostrobin (from the strobilurin class of chemistry). Because of its high specific activity, it has been effective against target fungi.

But Headline suddenly became ineffective.

“If you sprayed the field in 2016, and went back to that fields three to four weeks later, it started to turn brown,” Khan said.

The reason? Mutations.

One mutation resulted in complete resistance to the QOI fungicides.

“All the fungus had to do was change an amino acid at one position (in its genes) for another — an alanine changed to guanine,” Khan explained.

And that was that.

At the same time, it developed “reduced sensitivity” to another previously effective fungicide group — triazoles (also called “demetallization inhibitors”). This puts holes in the fungi’s cell membranes.

Khan started recommending using one new fungicide with another mode of action — “especially an older chemistry.” (The older fungicides are “multi-site” types, used since the 1970s.)

Mohammed Khan, a professor and sugar beet specialist for the University of Minnesota and North Dakota State University,  uses a battery-powered spore trap to monitor levels of Cercospora leaf spot disease at research plots near Foxhome, Minn. Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

Mohammed Khan, a professor and sugar beet specialist for the University of Minnesota and North Dakota State University, uses a battery-powered spore trap to monitor levels of Cercospora leaf spot disease at research plots near Foxhome, Minn. Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

The most popular older fungicides were ethylenbisdithiocarbamates. The EBDCs included trade names Mancozeb and Penncozeb. Other old chemistry are known as “tins” — triphenyltin hydroxide (TPTH). The common “coppers” were copper hydroxide and copper oxychloride..

A $200M hit

The 2016 season was the warmest and wettest in the 121-year weather record history for Minnesota. This was good for growing beets but devastating if you had cercospora that had become resistant to the previously most-effective fungicides.

“Because the best modes of action were no longer effective in 2016, our growers lost close to $200 million — less income to producers in North Dakota, Minnesota and Michigan,” Khan said.

From 2016 to 2020, growers in Southern Minnesota applied six to seven fungicide applications per year, always in mixtures, with mixed success, depending on the amount of rain.

A weather station at the sugar beet Cercospora leaf spot research plot near Foxhome, Minn., provides temperature (air and soil), relative humidity and precipitation data that is correlated with a spore trap to help scientists recommend the best way to fight yield- and quality-robbing disease. Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

A weather station at the sugar beet Cercospora leaf spot research plot near Foxhome, Minn., provides temperature (air and soil), relative humidity and precipitation data that is correlated with a spore trap to help scientists recommend the best way to fight yield- and quality-robbing disease. Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

QOI fungicides worked well until years like 2019, when repeated rains washed them off and they had to be reapplied. “The disease will overtake the plants. You will have low yields, very little to harvest,” he said.

In 2020, the southern Minnesota growers had effective disease control — with yields of nearly 30 tons per acre, with 17% sugar. In 2019, Southern Minnesota Beet Sugar Cooperative had reported a yield of 23.4 tons per acre and a sugar content of 15.63%; however, the 2019 season was further challenged by weeds, diseases and poor harvest conditions.

NDSU started urging seed companies to speed up work they already were doing to incorporate tolerance. The new cercospora improvements came through conventional breeding, not genetic modifications. KWS breeders had been finding strong cercospora tolerance in a broad range of wild beets.

Khan and his research team inoculate plots to allow cooperatives to rate sugarbeet varieties for their cercospora leaf spot resistance. He also studies fungicides for their effectiveness, as well how they work in mixes and rotations.

Mike Metzger, vice president of agriculture for Minn-Dak Farmers Cooperative at Wahpeton, N.D., has had the new CR+ varieties in his company’s research plots for two years. He describes cercospora as the co-op’s “No. 1 production problem.”

Metzger said that 60% of seed planted by Minn-Dak Farmers Cooperative at Wahpeton this year were the improved cercospora-resistant sugarbeet varieties. Khan said about 15% of the crop for Southern Minnesota at Renville also also are the new varieties.

All of Minn-Dak’s members this year were offered an opportunity to buy the new seed, and Metzger estimates that 80% to 85% did. The new seed came at about a $40 per acre cost above the typical seed price, which ranges from $200 to $250 an acre.

“It’s going to offset three sprays,” which Metzger and Khan say is at about $25 to $30 per spray.

Mohamed Khan, a North Dakota State University and University of Minnesota sugarbeet specialist, says new ‘improved cercospora leaf resistant” beet varieties were used on 60% of Minn-Dak Farmers Cooperative growers and 15% of Southern Minnesota Beet Sugar Co-op, and should be available to most growers nationwide in two to three years. 
Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

Mohamed Khan, a North Dakota State University and University of Minnesota sugarbeet specialist, says new ‘improved cercospora leaf resistant” beet varieties were used on 60% of Minn-Dak Farmers Cooperative growers and 15% of Southern Minnesota Beet Sugar Co-op, and should be available to most growers nationwide in two to three years.
Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

Metzger likened the new variety impact to the to “herd immunity” when it comes to COVID-19. Going to resistant varieties could drastically reduce the amount of fungus over a two-or three-year period.

“We don’t have to worry about that massive cercospora cloud hanging over our head. It gives us a chance to take a breath, hit the reset button,” he said.

Khan said the new cercospora-tolerant varieties appear to have tonnage yield comparable to approved sensitive varieties. The sugar concentration may be a little lower.

“But overall, the recoverable sucrose is as good as the other varieties we’ve had,” he said.

In June 2021, researchers inoculated sugar beets in research trials with  Cercospora leaf spot disease spores. They were just beginning to show symptoms on July 16, 2021. 
Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

In June 2021, researchers inoculated sugar beets in research trials with Cercospora leaf spot disease spores. They were just beginning to show symptoms on July 16, 2021.
Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

He said other seed companies (Crystal Beet Seeds, SESVanderHave, Hilleshog and Maribo) also are working toward commercializing resistant varieties.

While the cercospora-resistant varieties so far have come through conventional breeding, Khan said the industry is looking at developing other traits through genetic modification. Some on the horizon include triple-stack resistance to glyphosate (Roundup) glufosinate (Liberty) and dicamba perhaps in 2025 or 2026. The only sugarbeet GMOs now approved for use are for Roundup (glyphosate) resistance.

Mohammed Khan, a University of Minnesota and North Dakota State University extension sugar beet specialist,  pores through charts that show the effect and timing of different mixes and timing for fungicides to fight Cercospora leaf spot disease. Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

Mohammed Khan, a University of Minnesota and North Dakota State University extension sugar beet specialist, pores through charts that show the effect and timing of different mixes and timing for fungicides to fight Cercospora leaf spot disease. Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

Khan and his technicians in late June intentionally inoculate the entire site with cercospora leaf spot disease, accumulated from infected leaves from growers’ fields the previous year, mixed with a talcum powder.

Also, Khan’s larger job is to determine which fungicides are effective in combatting the disease.

The researchers apply the fungicides in applications in 10- to 14-day intervals (depending on rainfall) — about five to six applications across the entire season from late June into September. Khan applies the combinations to beets with varying levels of cercospora resistance. Those include varieties more susceptible than the “conventional, susceptible” growers would normally use.

“If something is working in my research site, it will work in a grower’s field,” he said.

Sugar beet research at Foxhome, Minn., includes a “spore trap.” It uses a vacuum to pull Cercospora leaf spot spores. The spores stick to a sticky tape, moving in a one-week cycle. Researchers have found they’re most prevalent between 5:30 a.m. and 8 a.m. Data from the study should improve fungicide timing.  Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek.

Sugar beet research at Foxhome, Minn., includes a “spore trap.” It uses a vacuum to pull Cercospora leaf spot spores. The spores stick to a sticky tape, moving in a one-week cycle. Researchers have found they’re most prevalent between 5:30 a.m. and 8 a.m. Data from the study should improve fungicide timing. Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek.

Part of Khan’s research is using fungicides with the improved varieties to see if he can reduce the fungicide applications and still get high yields. In some of the improved varieties he thinks he can use as few as one — or zero — applications in some years.

In the end, the samples are analyzed at an American Crystal Sugar Co. tare laboratory at East Grand Forks, Minn.

“We do calendar sprays — for growers who don’t want to scout,” he said. “If they they want good yields, they’ll probably have to spray every 10 to 14 days.”

Cercospora first attacks the oldest leaves, which produce the most sugar. The disease doesn’t hit younger leaves until late in the season. Those who scout do so based on leaf spots and daily infection values, some relying on scouts or consultants to determine disease severity and the best time to apply fungicides.

Mohamed Khan’s conducts Cercospora leaf spot research on a 25 acre cercospora leaf plot  at Foxhome, Minn., on parts of the Kevin Etzler farm. Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

Mohamed Khan’s conducts Cercospora leaf spot research on a 25 acre cercospora leaf plot at Foxhome, Minn., on parts of the Kevin Etzler farm. Photo taken July 16, 2021, at Foxhome, Minn. Mikkel Pates / Agweek

In a related study at the research plots, Khan is working with drones to aerially collect images to determine the amount of “brownness” that would indicate an infestation. That will be correlated to infestation data on the ground, and eventually cut the time and cost of scouting fields.

If the drone technology proves itself, Khan is working with an engineering colleague at NDSU to develop a sensor for agriculture that is also usable for detecting weeds in sugarbeets and other crops.ShareBecca Roberts 1268 Posts 0 Comments

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CRISPR sows seeds of change in agricultural biotechnology

Since its introduction in 2012, CRISPR-based genetic engineering technology has transformed biotechnology and opened new possibilities in biomedicine. Currently, CRISPR is driving development in yet another domain—agriculture. Although CRISPR has been slower to realize agricultural applications than biotechnology and biomedical applications, it is ready to help us cope with an array of agricultural challenges that include an expanding population, a rapidly warming climate, and a shrinking supply of arable land.

Nearly a decade after Charpentier and Doudna’s landmark study demonstrating that CRISPR systems could be programmed for targeted DNA cleavage in vitro (Jinek et al. Science 2012; 337(6096), 816–821), scientists have started to make good use of CRISPR systems in agricultural biotechnology (agbiotech). In fact, the first genome-edited agricultural product has already hit the market in Japan. This product is a tomato called the Sicilian Rouge High GABA. It was engineered by Sanatech Seed, and it is meant to help consumers reduce their blood pressure. If this product does well, it may encourage other agbiotech companies to ramp up their own CRISPR genome editing programs.

CRISPR has both practical and regulatory advantages over traditional plant breeding and genetic modification methods. Consequently, CRISPR is looking increasingly attractive to agbiotech companies that hope to engineer products that can improve human health and the environment.

“It’s all about genetic variability,” affirms Sam Eathington, PhD, the chief technology officer at Corteva Agriscience, one of the Big Four seed companies. “In some crops, we don’t have as much variability as we’d like. There are times that variability is locked up in parts of the genome that you just can’t unlock easily. Or you bring in a gene for improved disease resistance from a wild species that can intermate, but you bring along a whole bunch of stuff that’s detrimental.” CRISPR can overcome those obstacles, accessing that variability while removing unwanted baggage.

Read the complete article at www.genengnews.com.

Publication date: Thu 12 Aug 2021

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Wineries in California have been under siege for decades. There’s finally hope that grapevines can be saved from bacterial disease

Agostino Petroni | August 12, 2021

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Pierce's disease. Credit: California Department of Food and Agriculture
Pierce’s disease. Credit: California Department of Food and Agriculture

This article or excerpt is included in the GLP’s daily curated selection of ideologically diverse news, opinion and analysis of biotechnology innovation.In 1961, Adam Tolmach planted a five-acre vineyard on land he had inherited from his grandfather in the wine-growing region of Ventura County, California, a few miles east of Santa Barbara. As an undergraduate, Tolmach had studied grape growing and winemaking (areas of study known as viticulture and enology, respectively) and then worked for a couple of years at a winery not far from his grandfather’s land. In 1983, he started producing his own wines, which he sells under the Ojai Vineyard label.

Over the years, Tolmach’s grapevines began to suffer. The plants lost vigor and the leaves dried. It turned out the vineyard was affected by Pierce’s disease, a sickness that had long plagued southern California, but had become more severe in the 1990s after the invasion of the glassy-winged sharpshooter, a large leafhopper insect that feeds on plant fluids and can spread a bacterium known as Xylella fastidiosa, usually just called Xylella (pronounced zy-LEL’-uh). This bacterium has existed in the United States since as far back as the 1880s, and over the years, it has destroyed at least 35,000 acres of the nation’s vineyards.

Adam Tolmach. Credit: Ojai Vinyard

Tolmach witnessed the slow but certain death of his grapevines. By 1995, there were just too many missing plants, he said. So he decided to pull out the infected vineyard. To continue making wine, he bought grapes from other producers. Tolmach became a winemaker with no vineyard of his own.

Every year, American winemakers lose about $56 million worth of vines, while government agencies, nurseries, and the University of California system invest another $48 million in prevention efforts, according to research published in the journal California Agriculture. At least 340 plant species serve as hosts to Xylella, though the bacteria only harm some of them. Across the globe, Xylella has devastated orange trees in Brazil and olive fields in southern Italy, and recently a newly identified species, Xylella taiwanensis, has been infecting pear trees in Taiwan. As of now, there is no permanent solution. Each time a Xylella species has invaded a new region, it has proved impossible to eradicate.

Countries have long fretted about the potential for infected plant imports to spread the bacteria, and more recently, climate change has been identified as an additional threat, pushing the disease vectors’ habitat north, both in Europe and in the U.S. As winters become warmer, experts say, Xylella could enter new territories, upending their regional economies and landscapes.

Yet there might be some hope. After 40 years of crossbreeding European grape varieties with wild grapes, a plant geneticist recently patented five hybrid grapes that appear to be resistant to Pierce’s disease. While scientists caution that it’s not yet clear how long the resistance will endure, wine producers like Tolmach hope that these new grapes will allow their vineyards to flourish once again.

A variety of grape species are indigenous to America, and a recent study suggests that Native Americans might have used them to make alcoholic beverages more than 500 years ago. In North America, native varieties tend to have thick skin and an astringent, peppery, acidic taste that is quite different from the grapes used in most wines.

In the 1500s, Spanish settlers brought Vitis vinifera, the common European grapevine for winemaking, to Florida. Farmers never succeeded in cultivating European grapes in the new territory — after a few years, the plants would just die. Then, in the 1860s, the Los Angeles Vineyard Society led grape-planting efforts in the Santa Ana Valley. By 1883, there were a total of 50 wineries and 10,000 acres of grapevines. Then, just a couple of years later, the grapevines had all died inexplicably.

In 1889, the U.S. Department of Agriculture instructed one of the first formally trained American plant pathologists, Newton Pierce, to figure out what was killing the European grapevines. Pierce studied the disease, eventually speculating that it was caused by a microorganism, but he never identified one. Still, in recognition of his effort, the disease was eventually named after him.

In the 1970s, a University of California, Berkeley entomologist named Alexander Purcell helped solve the mystery. At the time, researchers were beginning to think Pierce’s disease was caused by bacteria but had yet to pin down a culprit. Purcell and his colleagues proved the then-unnamed Xylella was responsible by growing the bacterium from samples taken from plants infected by blue-green sharpshooters, and then directly infecting healthy plants with the lab-grown pathogen. Over time, a more complete picture of disease transmission emerged.

The glassy-winged sharpshooter feeds on the green stems and leaves of grapevine plants, which contain water and dissolved nutrients, Purcell told Undark. If the plant is infected with Xylella, some of the bacteria linger in the insect’s needle-like mouthparts. The next time the glassy-winged sharpshooter feeds upon a grapevine, the insect can transfer the Xylella to the new plant. Inside the plant’s vascular tissues, the bacteria multiply, obstructing the normal flow of water and nutrients and interfering with the plant’s metabolism and physiology — a process that ultimately kills the plant.

In the late 1980s, Purcell mapped swaths of the U.S. and Europe by how conducive they are to disease spread. Knowing that Xylella do not thrive in regions with cold winters, that are far from large bodies of water, and that lack a disease-carrying vector such as the glassy-winged sharpshooter, Purcell drew out maps by hand. He then marked the regions with the right combination of geographic and climatic conditions to allow for Pierce’s disease to spread, noticing a pattern emerge.

At the time, the European Union was not very concerned about Xylella, though Purcell contends that the bacteria had almost certainly arrived in the region. In talks and at conferences, he warned that European countries were facing a great danger. He urged the E.U. to increase its regulations of plant imports. Those warnings went unheeded, Purcell said, and in 2017, Pierce’s disease was first detected on the grapevines of the Spanish island of Mallorca, jeopardizing the future of winemaking there. Today, Xylella is spreading through the Mediterranean region and other parts of Europe — just as Purcell predicted.

The glassy-winged sharpshooter spreads Xylella bacteria when it feeds on the vascular tissues of plants. Credit: Courtesy of University of California, Riverside

Alberto Fereres, a Spanish entomologist and researcher at the Spanish National Research Council, is concerned about the devastating effects of the European outbreaks, including one in southern Italy that has infected and killed 20 million olive trees, more than a third of the region’s population. “[Xylella] is present in many more countries than we indeed thought,” Fereres said, adding that his research group recently discovered that the bacteria have been present in Spain for more than 20 years, but for much of that time it only lived in plants that don’t show symptoms of the disease.

Fereres hopes at least some plants will adapt to the presence of the bacteria and that farmers will be able to control the indigenous European vector, the meadow spittlebug, by tilling the land to kill the bug’s juveniles and placing barriers or nets to separate the insects from susceptible plants.

So far, the U.S. has largely used insecticides to get rid of infected insects. The Temecula Valley in California, for example, experienced a severe outbreak of Pierce’s disease in the late 1990s. Back then, stakeholders managed to defeat the disease in less than two years by introducing specific pesticides into the farming of grapevines.

Matt Daugherty, an entomologist at the University of California, Riverside, studied the resulting decline in Temecula’s glassy-winged sharpshooter population. He said the insect’s numbers remained low until around 2017, when the population exploded for a second time.

“Now the bad news is this,” Purcell said: “After about 18 years, the insect is now resistant to the insecticide.” In entomology, Purcell added, such resistance is common if the same insecticide is used year after year. He and Fereres maintain that pesticides are not a viable long-term solution to the problem. In some countries, this approach has also run up against public opinion. In Italy, for example, consumers have strongly opposed the use of pesticides on olive trees threatened by Xylella.

Rodrigo Almeida, a plant pathologist at the University of California, Berkeley, warns that climate change might worsen the situation: While low winter temperatures in many grape-growing regions have traditionally limited the spread of Pierce’s disease, the past few years have brought warmer winters, allowing Xylella to spread.Follow the latest news and policy debates on agricultural biotech and biomedicine? Subscribe to our newsletter.SIGN UP

“With warming temperatures and warmer winters, you’re going to have sort of more disease where you already have it, and you’re probably going to see the range expand north as well,” Almeida said. Warmer temperatures favor greater survival of the insects and increase the likelihood that an infection will persist through the winter. Almeida added that it’s difficult to predict precisely how much the disease will increase and how it will impact the new territories, but that there is the possibility that the disease will find a home in areas where a dry climate combines with warmer winters.

“We’re expecting things to get worse and worse,” Daugherty said.

Yet, in territories where European grapes die because of Xylella, wild indigenous grape varieties that are not a good fit for winemaking thrive. Those plants bear a unique gene that prevents them from succumbing to the disease, and that specific gene could be a counteroffensive to the bacteria and might well change the future of winemaking.

In 1989, University of California, Davis plant geneticist and viticulturist Andrew Walker inherited grapevine seeds that he was told were produced from crossbreeding two known Vitis species. But as the plants grew, he soon noticed they were behaving weirdly. For one thing, their vines had sprouted fine hairs along the stems. More importantly, the plants proved resistant to Pierce’s disease. Walker decided to investigate. Perhaps, he speculated, the parent plants, which were still flourishing in an abandoned vineyard owned by his university, had accidentally crossbred with the native grapevines that were growing wild nearby.

Indeed, this turned out to be the case. Vitis arizonica grows wild in the southwest U.S. and Mexico, and Walker matched the genetic fingerprint of the male V. arizonica in his own plants. The wild plant carries a dominant gene that passes along Pierce’s disease resistant traits to its offspring.

Sensing that this could lead to breakthrough for new varieties of grapevine, Walker began the slow process of crossbreeding. This technique goes back about 10,000 years and involves selectively breeding plants and animals with desired traits. In this case, Walker wanted to cross disease-resistant V. arizonica with winemaking varieties like cabernet sauvignon.

A grapevine leaf affected by Pierce’s disease. As the plant’s vascular structure is obstructed by bacteria, the flow of water and nutrients is impeded, and the leaves become brown and dry. Credit: Agricultural Research Service/USDA

The first generation’s seedlings all carried the gene for disease resistance. Walker selected the highest quality among them, and when the plants flowered, he crossed them again with various V. vinifera varieties. He did this for four to five generations, reaching a point where 97 percent of the plant’s genome came from V. vinifera and 3 percent came from V. arizonica. It took Walker about 20 years to develop these new plants, five varieties of which have been patented and given out to a few producers, and sold through a handful of nurseries. Tolmach, the winemaker from Ojai, was one of the few lucky ones to receive them.

“I guess what’s shocking to me is that the quality is there — these can be standalone wines by themselves,” said Tolmach. In 2017, he planted about 1,800 plants on 1.2 acres with four of Walker’s varieties, and he recently bottled the 2019 vintages. (These vintages won’t be available until this fall, when they will be priced between $30 and $40 per bottle, which is comparable to his vintages that use traditional grapes.) Tolmach said that his new plants are healthy and thriving with no sign of the disease, and he’s now thinking of planting more on a 10-acre vineyard that he purchased in northern Santa Barbara County.

Matt Kettmann, a California writer and wine critic who has been following Tolmach’s work for years, tasted Tolmach’s wines produced with resistant grape varieties. He said they are unique and interesting wines with characteristics reminiscent of wines of European heritage. He described Tolmach’s 2019 wine using Walker’s paseante noir grape as tasting of “black cherry, mocha, clove, baking spice,” while praising its “smooth texture and rich mouthfeel.” “That one,” said Kettmann, “was really kind of impressive to me.”

Kettmann anticipates that the new wines will be appreciated by connoisseurs, but he wonders how the larger American market will respond. Europeans emphasize the value of terroir — the taste imparted to a wine by a particular region’s soil, topography, and climate. Americans, on the other hand, tend to care more about the variety of the grape, like pinot gris, cabernet sauvignon, or zinfandel — and Walker’s varieties are entirely new.

“Tradition is a huge consideration in choosing wine varieties for winemaking. Can you name any new grape varieties introduced during the last 50 years that are now widely used for wine?” wrote Purcell in an email.

It’s also not clear whether new genotypes of Xylella might evolve to infect the hybrid grapes, Purcell and Fereres wrote to Undark. Currently, only a single gene confers the resistance. For this reason, it might be necessary to incorporate new resistance genes by crossbreeding additional varieties of grapevine, said Purcell.

Still, growers like Tolmach are excited by Walker’s resistant varieties, and some are planting them in areas that have been impacted by Xylella, Walker saidThough Tolmach has made wines with the new grapes exclusively, he suggests many wineries may opt to blend the grapes with other mainstream varieties.

For his part, Walker believes that any skepticism about his grapes’ novelty will fade in the face of climate change. “It is going to force people to reevaluate how we improve grapevines,” he said.

Agostino Petroni is a journalist, author, and a 2021 Pulitzer Reporting Fellow. His work appears in a number of outlets, including National Geographic, BBC, and Atlas Obscura. Find Agostino on Twitter @PetroniAgostino

A version of this article was originally posted at Undark and is reposted here with permission. Undark can be found on Twitter @undarkmag

The GLP featured this article to reflect the diversity of news, opinion and analysis. The viewpoint is the author’s own. The GLP’s goal is to stimulate constructive discourse on challenging science issues.

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