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Archive for the ‘Plant Pathogens’ Category

The Chilean cherry sector is worried about the necrotic spot virus

The Federation of Fruit Producers expressed its concern about the threat that the Prunus necrotic spot virus poses for the Chilean cherry industry, as it could cause them to lose plantations and part of the international market that buys this product.

In an interview with the newspaper La Tribuna, the president of Fedefruta, Jorge Valenzuela, said that, even though the virus’ incidence in the country is still being studied, they were already studying the cherries that have the virus to contain and control it. “This virus is constantly found in fruits, but it doesn’t always present symptoms,” Valenzuela stated.

“Fedefruta is working with the association of exporters and the Agricultural and Livestock Service (SAG) to teach producers what the symptoms of this virus are so they can identify it and know how to treat it,” he stressed. This will allow producers to carry out tests to detect the virus in time and stop its spread in the different agricultural properties that could face this problem.

However, one of the great difficulties that Fedefruta faces is that there still is no method to treat the virus. Thus, producers should remove the trees that show any symptoms from the orchards.

The Federation has proposed certain guidelines to face this agricultural disease in crops: “Healthy trees can defend themselves better against the virus if they have good agronomic management.” Thus, they recommend keeping the orchards in good sanitary conditions, as the first measure to combat the virus.

The union leader also asked agricultural producers not to panic: “We have restrictions in China, but we must make good selections so that there are no problems with the country later on.”

Valenzuela highlighted the joint work being developed between the Chilean Fruit Exporters Association AG (Asoex), Fedefruta (National Trade Union Federation of Fruit Producers), and the Chinese Government to eradicate the disease as soon as possible.

Source: latribuna.cl 

Publication date: Mon 13 Sep 2021

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Red rot disease: Punjab minister asks for survey to assess damage to sugarcane crop


PTI | Chandigarh | Updated: 08-09-2021 21:10 IST | Created: 08-09-2021 21:08 IST

Red rot disease: Punjab minister asks for survey to assess damage to sugarcane crop
Representative Image Image Credit: ANI

Punjab Cooperation Minister Sukhjinder Singh Randhawa on Wednesday asked district administrations of Gurdaspur and Jalandhar to conduct a survey to assess the damage caused to the sugarcane crop by red rot fungus disease.

Randhawa also asked the cooperation department to prepare a compressive report for the perusal of Chief Minister Amarinder Singh, who also holds the portfolio of agriculture, to work out an effective action plan in this matter.

Chairing a meeting to review the current situation that emerged after the outbreak of this disease, the minister directed the deputy commissioners to work in tandem with the Punjab Agricultural University, cane commissioner and others, to find ways and means to combat the disease to save the crop, according to an official statement.

Randhawa stressed the need to intensify research for exploring the factors that led to a sudden attack by fungus on sugarcane.

He appealed to the cane growers not to panic in the wake of disease rather he asked the authorities to identify the hotspot areas to effectively tackle the fungus.

Joining the deliberations through video conferencing, S K Pandey, principal scientist and head of sugarcane, Breading Institute, Regional Centre, Karnal, said this disease had already affected the sugarcane crop in Uttar Pradesh and Haryana in the past due to the problem of waterlogging.

He, however, said that intensive research in this regard revealed that ‘Co 0238’ variety of sugarcane was mainly prone to this fungus and the farmers in these states who had suffered substantial losses were told not to grow this variety in future.

(This story has not been edited by Devdiscourse staff and is auto-generated from a syndicated feed.)

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Hans News Service

Amalapuram: Coconut growers fear spread of Black Scorch disease to plantation Hans News Service   |  2 Sep 2021 1:23 AM IST

Coconut growers fear spread of Black Scorch disease to plantation  In Konaseema region, coconut plantation in 15 acres, around 880 trees affected and due to Black Scorch disease The Chief Minister instructs the officials to form a scientific committee to investigate the issue Amalapuram: ‘Kerala’ of Andhra Pradesh, as Konaseema is known for its abundant coconut plantation in the region, grip of fear as the money fetching coconut trees are adversely affected by a strange and peculiar disease called ‘Black Scorch’ disease in Nellivaripeta, Billakuduru village, Kothapeta mandal of East Godavari district Around 880 coconut trees were destroyed in 15 acres due to the disease. Worried of the spread of disease to other trees, many coconut farmers requested the scientists concerned to find a solution to eradicate the disease.

The people of this region solely dependent on the sale of coconuts livelihood and coconuts are exported to various places in the state as well as other states. The farmers allege that the salt water released by the borewells which were dug by ONGC lead to the cause of the disease to the plantation. The experts from YSR Horticulture University visited the area and studied about the nature and cause of the disease. With their expertise they could successfully prevent the spread of the disease to the surrounding trees.

The experts also conducted the water analysis and soil tests, but they couldn’t exactly diagnose the nature of the disease. The MLAs of Konaseema and officials brought the issue to the notice of the Chief Minister YS Jagan Mohan Reddy. The Chief Minister instructed the officials to appoint an expert committee to find cause of the disease and sort out the issue. The farmers appealed the Chief Minister not only curb the spread of the disease including the steps to root out its horizon, but to come to their rescue.

Horticulture officer PBS Amarnath told “The Hans India” that The coconut trees in Konaseema area attracted Black scorch disease in Nellivaripeta, Billakuduru village, Kothapeta mandal of East Godavari district and 880 coconut trees in 15 acres were already died due to the disease. He said that they spent nearly Rs 80,000 to 1 lakh to conduct the tests. He advised the government to invest few lakhs to conducts these types of tests in the future. He added that they could not conduct certain other tests due to lack of funds.

https://www.thehansindia.com/andhra-pradesh/amalapuram-coconut-growers-fear-spread-of-black-scorch-disease-to-plantation-704598

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From PestNet

Palm tree disease in Florida transmitted by traveling bug from Jamaica

Phys.Org

by American Phytopathological Society

What began as a curious survey of an insect in Florida revealed a much larger network of movement across the Caribbean basin. Haplaxius crudus, commonly known as the American palm cixiid, transmits phytoplasmas (bacteria that cause plant diseases) in palm. The American palm cixiid is known to transmit lethal yellowing disease and lethal bronzing disease, both of which are lethal to a variety of palm species, especially coconut and date palms.

While many scientists have assumed these pathogens migrated to Florida in infected plants, Brian Bahder at the University of Florida wondered if the real culprits were the insects themselves. To test this suspicion, Bahder and his colleagues began by categorizing the insect’s DNA in Florida, where they found four distinct groups.

Next they looked beyond the United States and tested populations in Costa Rica, Colombia, and Jamaica, three places that were distinct and relatively isolated. They found different insect DNA in Costa Rica and Colombia. In Jamaica, however, they found an exact match to one of the groups in Florida.

Read on: https://phys.org/news/2021-09-palm-tree-disease-florida-transmitted.html Haplaxius_crudus

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From PestNet

Saturday, 04 September 2021 10:28:00

Grahame Jackson posted a new submission ‘High altitudes no longer protect pine trees from disease’

Submission

High altitudes no longer protect pine trees from disease

erath.com

ByAlison Bosman

Earth.com staff writer

Researchers from UC Davis have gathered some of the first scientific evidence that climate change can affect the distribution of pathogens. The team studied the incidence of white pine blister rust in the forests of the Sequoia and Kings Canyon National Parks. White pine blister rust is caused by a fungus Cronartium ribicola that infects several types of pine trees, including whitebark pine, and has caused serious damage to white pine populations in the United States. 

The pathogen was introduced by accident in 1900 and is an invasive species that inevitably causes tree mortality. Part of the life cycle of C. ribicola is completed in secondary hosts, namely currant and gooseberry plants.

In the past, blister rust infections did not occur in high-altitude forests because the pathogen prefers warmer, milder conditions. Consequently, the forests above the Sequoia and Kings Canyon National Parks acted as a refuge from this disease. However, with changing climatic conditions, the pathogen has begun to infect trees that are higher up the slopes. 

“Because pathogens have thermal tolerances, we are seeing expansions and contractions in this disease’s range,” said study lead author Joan Dudney, a postdoctoral researcher at UC Davis in the lab of Professor Andrew Latimer. “Climate change isn’t so much leading to widespread increases in this disease but rather shifting where it is emerging.”

The researchers used data from long-term monitoring plots in the National Park forests in the southern Sierra Nevada mountains. Data spanned the period between 1996 and 2016, which is considered to be a warmer, drier period than normal. Observations from over 7,800 potential host trees were included and, in addition, the scientists measured stable isotope ratios in pine needles. 

They found that the optimal climatic conditions for blister rust moved, during the 20-year study period, from lower to higher elevations. The incidence of blister rust decreased by 5.5 percent in the more arid, lower-elevation forests and increased by 7 percent in forests at cooler, higher elevations.

“Our study clearly demonstrates that infectious plant diseases are moving upslope, and they’re moving fast,” said Dudney. “Few pines are resistant to what is basically a Northern Hemisphere white pine pandemic.”

The high-elevation refuges where pine trees were protected from pathogens by the inhospitable conditions, are now under threat because of climate warming; conditions there are becoming tolerable to the diseases and pests. Pathogens are expanding their ranges into these higher elevation areas while contracting in the lower areas where the climate is now too warm and dry for their survival.

“It’s kind of a race between evolution and climate change,” said Professor Latimer. “So far, climate change is winning.”

Although it seems inevitable that blister rust will impact severely on white pine populations as the climate becomes warmer, Dudney stated that employing disease prevention methods could help to slow the spread of the disease. 

The study is published recently in the journal Nature Communications.

Saturday, 04 September 2021 10:28:00


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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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Science News

Viruses can kill wasp larvae that grow inside infected caterpillars

A new study is a take on the adage, “The enemy of my enemy is my friend.”

picture of a green caterpillar-like creature walking across a leaf
A group of proteins found in some insect viruses as well as some insects (such as this beet armyworm) can kill the larvae of parasitic wasps, protecting the caterpillars that those wasps exploit to lay eggs.JOHN CAPINERA, UNIVERSITY OF FLORIDA/BUGWOOD.ORG (CC BY-NC 3.0 US)

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By Erin Garcia de Jesús

JULY 29, 2021 AT 2:00 PM

When parasitic wasps come calling, some caterpillars have a surprising ally: a viral infection. 

Insects called parasitoid wasps lay their eggs inside young moth larvae, turning the caterpillars into unwitting, destined-to-die incubators for possibly hundreds of wasp offspring. That’s bad news for viruses trying to use the caterpillars as replication factories. For the caterpillars, viral infections can be lethal, but their chances of survival are probably higher than if wasps choose them as a living nursery.

Now, a study shows how certain viruses can help caterpillars stymie parasitoid wasps. A group of proteins dubbed parasitoid killing factor, or PKF, that are found in some insect viruses are incredibly toxic to young parasitoid wasps, researchers report in the July 30 Science.

The new finding shows that viruses and caterpillars can come together to fight off a common wasp enemy, says study coauthor Madoka Nakai, an insect virologist at Tokyo University of Agriculture and Technology. A parasitoid wasp would kill a host that the virus needs to survive, so the virus fights for its home. “It’s very clever,” Nakai says.

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What’s more, some moth caterpillars make the wasp-killing proteins themselves, the team found. It’s possible that in the distant past, a few moths survived a viral infection and “got some presents” in the form of genetic instructions for how to make the proteins, says study coauthor Salvador Herrero, an insect pathologist and geneticist at the University of Valencia in Spain. Those insects could have then passed the ability down to offspring. In this case, “what doesn’t kill you makes you stronger,” Herrero says.

Previous studies had shown that viruses and insects, including moths, can swap genes with each other. The new finding is one of the latest examples of this activity, says Michael Strand, an entomologist at the University of Georgia in Athens who was not involved in the work.

“Parasite-host relationships are very specialized,” he says. “Factors like [PKF] are probably important in defining which hosts can be used by which parasites.” But whether caterpillars stole the genetic instructions for the proteins from viruses or if viruses originally stole the instructions from another host remains unclear, Strand says.  

Researchers discovered in the 1970s that virus-infected caterpillars could kill parasitoid wasp larvae using an unknown viral protein. In the new study, Herrero and colleagues identified PKF as wasp-killing proteins. The team infected moth caterpillars with one of three insect viruses that carry the genetic blueprints to make the proteins. Then the researchers either allowed wasps to lay their eggs in the caterpillars or exposed wasp larvae to hemolymph — the insect equivalent of blood — from infected caterpillars.  

Virus-infected caterpillars were poor hosts of the parasitoid wasp Cotesia kariyai; most young wasps died before they had the chance to emerge from the caterpillars into the world. Hemolymph from infected caterpillars was also an efficient killer of wasp larvae, typically destroying more than 90 percent of offspring.

C. kariyai wasp larvae also didn’t survive in caterpillars, including the beet armyworm (Spodoptera exigua), that make their own PKF. When the researchers blocked the genes for the proteins in these caterpillars, the wasps lived, a sign that the proteins are key for the caterpillars’ defenses.

Some parasitoid wasps, including Meteorus pulchricornis, weren’t affected by PKF from the viruses and also beet armyworms, allowing the wasp offspring to thrive inside caterpillars. That finding suggests that the wasp-fighting ability is species-specific, says Elisabeth Herniou, an insect virologist at CNRS and the University of Tours in France who was not involved in the work. Pinpointing why some wasps aren’t susceptible could reveal the details of a long-held evolutionary battle between all three types of organisms.  

The study highlights that “single genes can interfere with the outcome of [these] interactions,” Herniou says. “One virus may have this gene and the other virus doesn’t have it,” and that can change what happens when virus, caterpillar and parasitoid all collide.

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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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Sri Lanka’s fast spreading leaf disease could wipe out rubber in fertilizer ban, industry warns

Wednesday September 1, 2021 1:05 pm

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ECONOMY NEXT – Sri Lanka’s large rubber industry has warned of a 15 to 20 percent production drop this year as leaf disease spread rapidly without enough fungicide to combat it or fertilizer to help trees recover amid an agro-chemical import ban.

Growers may be forced to shift to alternative crops as yields fall and immature plants are also hit, industry officials said.

About 20,000 hectares out of 107,000 cultivated by large farms and small holders have been hit by Pestalotiopsis, fungal leaf disease, Colombo Rubber Traders Association, an industry grouping said.

Sri Lanka’s President Gotabaya Rajapaksa has banned agro-chemicals to save foreign currency and to stop non-communicable diseases.

Sri Lanka’s Government Medical Officers Association has said according to Pliny the elder, ancient Sri Lankans lived for 140 years, when there were no agro-chemicals.

“This leaf disease is possibly best described as the equivalent of COVID-19 in the case of the rubber industry, considering both its devastation and the rapid speed at which it is spreading,” Manoj Udugampola Vice Chairman of the Colombo Rubber Traders’ Association (CRTA) said in a statement.

Farms needed fungicides, Carbendazim and Hexaconazole and also fertilizer to help the trees recover leaves.

But after the fertilizer ban, neither additional quantities or nor usual volumes were available.

Earlier in the year, some inputs had been available at the double the price before the ban, but there was no fertilizer in the market.

By July/August mature and immature plants needed fertilizer to use in recommended amounts.

“By around April – May this year we were already seeing a 10 to 20 percent reduction in output from rubber plantations due to Pestalotiopsis,” Udara Premathilake, Director Plantations (Rubber), Kelani Valley Plantations PLC said.

“Since we continue to incur huge fixed costs including labour costs in running our operations, the reduction in output is reducing our revenue substantially and therefore our profits, so the industry is fast becoming unviable.

“At this rate by year-end we are looking at a 15% to 20% reduction of the annual output. We are not sure where the industry would stand by next year.

“When this disease spreads to immature plants, their long-term growth will be badly affected.

“Since rubber trees have a life span of around 30 years this translates to a long-term decline in production. As concerted action should be taken at least now, or the industry will be unviable both in the short and the long-run.”

Companies were already looking at other crops like cardamom, pepper and cinnamon, he said.

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Phys.Org

Infection method behind ‘crop killer’ bacteria revealed

by Nanyang Technological University

Infection method behind ‘crop killer’ bacteria revealed
Credit: Nanyang Technological University

An interdisciplinary team of scientists from NTU Singapore has identified, for the first time, a key mechanism by which a dangerous plant disease can infect crops.

The Xanthomonas bacteria, known as the “crop killer,” is a globally prevalent bacterium capable of infecting 400 different plant species. It causes bacterial spots and blights in the leaves and fruits of the plants it infects. In some cases, once the disease takes root, a farmer’s only recourse is to cut down and burn the entire crop of plants to stem the spread of disease.

The NTU researchers identified the exact cellular-level mechanism by which the bacteria can penetrate and hijack a plant’s immune system, therefore leaving them vulnerable to infection.

The Xanthomonas bacteria infects and damages plants by injecting toxic proteins into the plant host. These proteins hijack and take over the plant’s normal biological processes, preventing them from mounting an immune response.

The research team discovered that the toxic proteins interacts with plant cells like liquid droplets, allowing the bacteria protein to “glue” onto the plant cell and merge into it. This lets the Xanthomonas bacteria infiltrate and invade the plant cell, leaving it vulnerable to infection.

Understanding exactly how plants and crops are infected by bacteria is a crucial step in developing methods to prevent their infection and produce crops that can resist the disease.

The team has obtained a provisional patent for a toolkit they have developed that allows scientists to replicate the infection process. This will allow researchers to test potential solutions for strengthening crop immunity in laboratory settings. It also has potential applications for future synthetic biology and agri-food technology.


Explore furtherSymbiotic bacteria in root cells may be key to producing better crops, study finds


Provided by Nanyang Technological University

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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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Article text (excluding photos or graphics) © Imperial College London.

Photos and graphics subject to third party copyright used with permission or © Imperial College London.

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Hayley Dunning
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