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Archive for the ‘Host plant resistance’ Category

China develops GM corn variety to combat yield-cutting fall armyworm

Dong Xue | CGTN | April 12, 2021

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Credit: Miaoli County Agriculture Office
Credit: Miaoli County Agriculture Office

This article or excerpt is included in the GLP’s daily curated selection of ideologically diverse news, opinion and analysis of biotechnology innovation.

Food security is a major policy issue in China. To strengthen the nation’s seed industry, the country has approved a series of supporting policies, including in South China’s Hainan Province.

Like James Bond once said, “Nothing is impossible.” Lyu Yuping, a veteran plant breeder, had a similar belief and so [he] named his genetically modified corn seed “the 007”.

Lyu has devoted himself to agricultural technology and the seed breeding industry for more than two decades. He believes the corn seeds he’s developed are the real deal.

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LSU student identifies fungus causing soybean taproot decline

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TAGS: CROP DISEASELSUGarciaArocajpg.jpgTeddy Garcia-Aroca, an LSU Ph.D. student, holds a sample of a fungus he found and named that causes the disease soybean taproot decline.Discovery just “tip of the iceberg” as scientists strive to learn more about this devastating soybean disease.

Bruce Shultz, Louisiana State University | Apr 13, 2021

An LSU graduate student has identified and named a new species of fungus that causes a devastating soybean disease. 

LSU doctoral student Teddy Garcia-Aroca identified and named the fungus Xylaria necrophora, the pathogen that causes soybean taproot decline. He chose the species name necrophora after the Latin form of the Greek word “nekros,” meaning “dead tissue,” and “-phorum,” a Greek suffix referring to a plant’s stalk. 

“It’s certainly a great opportunity for a graduate student to work on describing a new species,” said Vinson Doyle, LSU AgCenter plant pathologist and co-advisor on the research project. “It opens up a ton of questions for us. This is just the tip of the iceberg.” 

Taproot decline

The fungus infects soybean roots, causing them to become blackened while causing leaves to turn yellow or orange with chlorosis. The disease has the potential to kill the plant. 

“It’s a big problem in the northeast part of the state,” said Trey Price, LSU AgCenter plant pathologist who is Garcia-Aroca’s major professor and co-advisor with Doyle. 

“I’ve seen fields that suffered a 25% yield loss, and that’s a conservative estimate,” Price said. Heather Kellytaproot decline in soybeans

Yellowing leaves are early symptoms of taproot decline in soybeans.

Louisiana soybean losses from the disease total more than one million bushels per year. 

Price said the disease has been a problem for many years as pathologists struggled to identify it. Some incorrectly attributed it to related soybean diseases such as black-root rot. 

“People called it the mystery disease because we didn’t know what caused it.” 

Price said while Garcia-Aroca was working on the cause of taproot decline, so were labs at the University of Arkansas and Mississippi State University. 

Price said the project is significant. “It’s exciting to work on something that is new. Not many have the opportunity to work on something unique.” 

Research 

Garcia-Aroca compared samples of the fungus that he collected from infected soybeans in Louisiana, Arkansas, Tennessee, Mississippi and Alabama with samples from the LSU Herbarium and 28 samples from the U.S. National Fungus Collections that were collected as far back as the 1920s. 

Some of these historical samples were collected in Louisiana sugarcane fields, but were not documented as pathogenic to sugarcane. In addition, non-pathogenic samples from Martinique and Hawaii were also used in the comparison, along with the genetic sequence of a sample from China. 

Garcia-Aroca said these historical specimens were selected because scientists who made the earlier collections had classified many of the samples as the fungus Xylaria arbuscula that causes diseases on macadamia and apple trees, along with sugarcane in Indonesia. But could genetic testing of samples almost 100 years old be conducted? “It turns out it was quite possible,” he said. 

DNA sequencing showed a match for Xylaria necrophora for five of these historical, non-pathogenic samples — two from Louisiana, two from Florida, and one from the island of Martinique in the Caribbean — as well as DNA sequences from the non-pathogenic specimen from China. All of these were consistently placed within the same group as the specimens causing taproot decline on soybeans. 

Why now? 

Garcia-Aroca said a hypothesis that could explain the appearance of the pathogen in the region is that the fungus could have been in the soil before soybeans were grown, feeding on decaying wild plant material, and it eventually made the jump to live soybeans. 

Arcoa’s study poses the question of why the fungus, after living off dead woody plant tissue, started infecting live soybeans in recent years. “Events underlying the emergence of X. necrophora as a soybean pathogen remain a mystery,” the study concludes. 

But he suggests that changes in the environment, new soybean genetics and changes in the fungal population may have resulted in the shift. 

The lifespan of the fungus is not known, Garcia-Aroca said, but it thrives in warmer weather of at least 80 degrees. Freezing weather may kill off some of the population, he said, but the fungus survives during the winter by living on buried soybean plant debris left over from harvest. It is likely that soybean seeds become infected with the fungus after coming in contact with infected soybean debris from previous crops. These hypotheses remain to be tested. 

Many of the fungal samples were collected long before soybeans were a major U.S. crop, Doyle said. “The people who collected them probably thought they weren’t of much importance.” 

Garcia-Aroca said this illustrates the importance of conducting scientific exploration and research as well as collecting samples from the wild. “You never know what effect these wild species have on the environment later on.” 

What’s next? Now that the pathogen has been identified, Price said, management strategies need to be refined. Crop rotation and tillage can be used to reduce incidence as well as tolerant varieties. 

“We’ve installed an annual field screening location at the Macon Ridge Research Station where we provide taproot decline rating information for soybean varieties,” Price said. “In-furrow and fungicide seed treatments may be a management option, and we have some promising data on some materials. However, some of the fungicides aren’t labeled, and we need more field data before we can recommend any.” 

He said LSU, Mississippi State and University of Arkansas researchers are collaborating on this front. 

Doyle said Garcia-Aroca proved his work ethic on this project. “It’s tedious work and just takes time. Teddy has turned out to be very meticulous and detailed.” 

The final chapter in Garcia-Aroca’s study, Doyle said, will be further research into the origins of this fungus and how it got to Louisiana. Source: Louisiana State University, which is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all its subsidiaries are not responsible for any of the content contained in this information asset.  

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Fall armyworm ‘worsens hunger among smallholders’

maize farm

Maize farmer inspecting her crops. Copyright: Axel Fassio/CIFORCC BY-NC-ND 2.0

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  • Fall armyworm destroys maize worth almost US$5 billion annually in 12 African countries
  • In a Zimbabwe study, the pest increased likelihood of hunger by 12 per cent
  • Farmers need cost-effective, environmentally sustainable control measures, experts say
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By: Onyango Nyamol

[NAIROBI] The invasive crop pest fall armyworm is well known for its devastating effects on maize yields in Africa, but few studies have been done on its broader impact on poverty levels and food security.

Now a study in Zimbabwe has found that smallholder maize-growing households blighted by fall armyworm are more likely to experience hunger and could see their income almost halved in severe cases, highlighting the urgency of strategies to tackle the pest.

“Our study suggests that the outbreak is threatening food security and negatively affecting farmers’ livelihoods, hence urgent actions are needed.”

Justice Tambo, CABI

According to the study, estimates from 12 maize‐producing countries in Sub-Saharan Africa including Benin, Cameroon, Ethiopia, Ghana, Malawi, Mozambique, Nigeria, Tanzania, Uganda, Zambia and Zimbabwe indicate that without control measures, the pest could cause maize losses of up to 17.7 million tonnes, translating into revenue loss of up to almost US$5 billion a year.

But researchers say that the negative impacts of the pest are far more than yield losses, with the potential to significantly impact food security and livelihoods.

The study, published in Food and Energy Security last month (15 March), shows that households affected by fall armyworm were 11 per cent more likely to experience food shortages, while their members had a 13 per cent higher likelihood of going to bed hungry or a whole day without eating. It also found that found that severe levels of infestation reduced per capita household income by 44 per cent.

“Our study suggests that the outbreak is threatening food security and negatively affecting farmers’ livelihoods, hence urgent actions are needed to address the menace posed by fall armyworm,” says Justice Tambo, the study’s lead author and a socio-economist at the Centre for Agriculture and Bioscience International (CABI, the parent organisation of SciDev.Net).

According to the study, fall armyworm was first reported in Zimbabwe during the 2016 and 2017 cropping season, and has continued to spread in subsequent seasons.

Researchers used survey data from 350 smallholder maize-growing households in six of Zimbabwe’s main maize production provinces. Data was collected in September 2018 by CABI in collaboration with Zimbabwe Plant Quarantine and Plant Protection Research Services Institute.

“We decided to conduct this study to provide evidence [of] how the fall armyworm outbreak is affecting farmers’ livelihoods beyond reductions in maize yields,” Tambo says. “While fall armyworm cannot be eradicated, taking actions to at least prevent severe level of infestation can significantly reduce welfare losses in terms of income and food security.”

Boddupalli Prasanna, director of the global maize programme at the International Maize and Wheat Improvement Center, tells SciDev.Net that fall armyworm is a serious concern to resource-constrained smallholders who have multiple challenges to tackle.

“We certainly need to provide effective, scalable and affordable technologies to the farming communities to combat the pest in a sustainable manner. Farmers cannot afford to rely on expensive chemical pesticides to and control fall armyworm,” says Prasanna, who was not involved in the study.

https://www.buzzsprout.com/1257893/8247114-in-africa-music-is-life-and-health?client_source=small_player&iframe=true&referrer=https://www.buzzsprout.com/1257893/8247114-in-africa-music-is-life-and-health.js?container_id=buzzsprout-player-8247114&player=small
Prasanna adds that there is no single specific technology that can provide sustainable control of a pest like fall armyworm.

“We need to adopt an integrated pest management (IPM) strategy, including effective integration of improved varieties with resistance to the pest, environmentally safer pesticides, biological control … and good agronomic practices,” he says. “We need to [increase] extensive awareness among extension agents and farming communities about IPM strategy for the control of fall armyworm.”

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According to Tambo, the findings have implications for policymakers, researchers and farmers. Farmers need to adopt low-risk pesticides products such as biopesticides, and combine them with safe non-chemical options including rotation and intercropping with other crops such as beans and cassava, he explains.

This piece was produced by SciDev.Net’s Sub-Saharan Africa English desk.

References

Justice A. Tambo and others Impact of fall armyworm invasion on household income and food security in Zimbabwe (Food and Energy Security, 15 March 2020)

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ToBRFV resistant tomatoes

In 2020, Enza Zaden announced the discovery of the tomato brown rugose fruit virus (ToBRFV) High Resistance gene, a complete solution for ToBRFV. Since the announcement, we’ve worked hard with resistant trials material achieving excellent results. “We see no symptoms at all in the plants, while the disease pressure is very high,” says Oscar Lara, Senior Tomato Product Specialist, about the first trials in Mexico.

No symptoms at all
At the Enza Zaden trial location in Mexico, the high resistance (HR) varieties are placed next to susceptible ones. There you can clearly see the difference. The susceptible tomato varieties show different foliage disorders such as a yellow mosaic pattern. The affected plants also stay behind in growth.

“You can clearly see how well our high resistant varieties withstand ToBRFV,” says Oscar Lara. “In comparison to the plants of susceptible varieties, the resistant ones look very healthy with a dark green colour, show no symptoms at all and have good growth. All our trialled HR tomato varieties do not show any symptoms at all.”

Exciting news
Enza Zaden is running parallel tests in different countries with varieties with high resistance to ToBRFV. “Our trials in Europe, North America, and the Middle East show that we have qualitatively good tomato cultivars with a confirmed high resistance level,” says Kees Könst, Crop research Director. “This is exciting news for all parties involved in the tomato growing industry. We know there is a lot at stake for our customers, so we continue to work hard to make HR varieties available for the market. We expect to have these ready in the coming years,” says Könst.

High performing and high resistance
Enza Zaden has a long history in breeding tomatoes. “We have an extended range of tomato varieties, from large beef to tasty vine tomatoes (truss tomatoes) and from baby plum tomatoes to pink varieties for the Asian market. This basis of high performing varieties combined with the gene we discovered, will enable us to deliver the high performing varieties with high resistance to ToBRFV.”

Why is a high resistance level so critical?
“With an intermediate resistance (IR) level, the virus propagation is delayed but ToBRFV can still enter tomato plants – plants that may eventually show symptoms,” says Könst. “With a high resistance level, plants and fruits do not host the virus at all. This means they won’t be a source for spreading the virus and that the detection test will come back negative. Growing a variety with high resistance can be the difference between making a profit or losing the crop.”For more information Enza Zadeninfo@enzazaden.com
www.enzazaden.com

Publication date: Tue 13 Apr 2021

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New tomato varieties in the fight against ToBRFV

The Italian company TomaTech is making great progress in the fight against ToBRFV. Starting next season, commercial varieties with intermediate resistance will be available. These include date tomatoes, midi plum and a number of colored varieties, both loose and on the vine.

This variety renewal starts with the date variety Dormaplum, which is described by TomaTech as the perfect tomato. It is very sweet, with a bright color and a uniform size, a weight of 16 grams and a Brix degree between 9 and 10. The balance between sweetness, acidity and structure is excellent.

The plant has an extraordinary high yield, suitable for long cycles and ideal for unheated greenhouses. TomaTech recommends grafting with two buds, and can be transplanted between the end of August and October.

The tomatoes have a long shelf life and are resistant to ToMV, Ff, TYLCV, ToBRFV. For those interested, seeds are available for trials.

Dormaplum, moreover, is a variety launched in southern Europe in 2020 which, despite numerous difficulties and limitations due to Covid-19, is proving to be an exceptional agronomic and commercial success.

For those who are instead looking for larger fruits, TomaTech offers cluster plums – still in the research phase – which seem very promising and are already available for long cycles with transplanting in August/October in Sicily and springtime in Lazio and Campania. Here too, free samples are available on request. To complete the current ToBRFV resistant/tolerant variety range there are three coloured specialities: ‘Tomelody’, ‘Cantando’ and ‘Tiny Tom Orange’.

Tomelody stands out for its sweetness, a tasty lemon-colored date variety with a distinctive shape and rich flavor. Perfect as a snack, light and healthy. High yield with more than 25 fruits per cluster of 15-17 grams each. The plant is resistant to Fol:0, ToMV, ToBRFV and is extremely versatile and suitable for all seasons.

Cantando is an orange date tomato with a high palatability, a Brix value between 8 and 10 and a smooth texture. The plant is very generative, well balanced with short internodes and resistant against Vd, Fol:0.1, ToMV, Mj, ToBRFV. The variety is suitable for transplanting between September and October.

Tiny Tom Orange is a sweet, fruity and aromatic orange date tomato. They weigh only 12 grams and have a Brix value ranging from 9 to 10. The variety is resistant to Vd, Fol:0.1, ToMV, Mj and ToBRFV.

 “At TomaTech, we are aware that the fight against ToBRFV is far from over, but we are confident in the work done. We are now able to launch these promising varieties and more will follow. So far, we have a valuable tool to contain this disease,” said the TomaTech research team.

For more information:
TomaTech
+39 351 7614 587
www.tomatech.it

Publication date: Wed 17 Mar 2021
© HortiDaily.com

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Perceiving predators: Understanding how plants ‘sense’ herbivore attack

by Tokyo University of Science

Perceiving predators: Understanding how plants 'sense' herbivore attack
Recently, Professor Gen-ichiro Arimura from Tokyo University of Science, Japan, encapsulated the research on the herbivory-sensing mechanism of plants through elicitors. Commenting of the immense value of these elicitors, Prof. Arimura states, “This review focuses mainly on elicitors because they are timely, novel, and have potential biotechnological applications.” Credit: Gen-ichiro Arimura, Tokyo University of Science

Nature has its way of maintaining balance. This statement rightly holds true for plants that are eaten by herbivores—insects or even mammals. Interestingly, these plants do not just silently allow themselves to be consumed and destroyed; in fact, they have evolved a defense system to warn them of predator attacks and potentially even ward them off. The defense systems arise as a result of inner and outer cellular signaling in the plants, as well as ecological cues. Plants have developed several ways of sensing damage; a lot of these involve the sensing of various “elicitor” molecules produced by either the predator or the plants themselves and initiation of an “SOS signal” of sorts.

In a recently published review in the journal Trends in Plant Science, Professor Gen-ichiro Arimura from Tokyo University of Science, Japan, encapsulates the research on the herbivory-sensing mechanism of plants through elicitors. Commenting of the immense value of these elicitors, Prof. Arimura states, “This review focuses mainly on elicitors because they are timely, novel, and have potential biotechnological applications.”

When the same herbivorous animal comes to eat the plant multiple times, the plant learns to recognize its feeding behavior and records the “molecular pattern” associated with it. This is termed “herbivore-associated molecular patterns” or HAMPs. HAMPs are innate elicitors. Other plant elicitors include plant products present inside cells that leak out because of the damage caused by herbivory. Interestingly, when an herbivorous insect eats the plant, the digestion products of the plant cell walls and other cellular components become part of the oral secretions (OS) of the insect, which can also function as an elicitor!

Prof. Arimura highlights the fact that with the advancement of high-throughput gene- and protein-detecting systems, the characterization of elicitors of even specific and peculiar types of herbivores, such as those that suck cell sap and do not produce sufficient amounts of OS, has become possible. The proteins present in the salivary glands of such insects could be potential elicitors as they enter the plant during feeding. He explains, “RNA-seq and proteomic analyses of the salivary glands of sucking herbivores have led to the recent characterization of several elicitor proteins, including a mucin-like salivary protein and mite elicitor proteins, which serve as elicitors in the leaves of the host plants upon their secretion into plants during feeding.”

The review also highlights some peculiar elicitors like the eggs and pheromones of insects that plants can detect and initiate a defense response against. In some special cases, the symbiotic bacteria living inside the insect’s gut can also regulate the defense systems of the plants.

And now that we have understood different types of elicitors, the question remains—what signaling mechanisms do the plants use to communicate the SOS signal?

So far, it has been hypothesized that the signaling is made possible by proteins transported through the vascular tissue of plants. Interestingly, there is evidence of airborne signaling across plants, by a phenomenon called “talking plants.” Upon damage, plants release volatile chemicals into the air, which can be perceived by neighboring plants. There is also evidence of epigenetic regulation of defense systems wherein plants maintain a sort of ‘genetic memory’ of the insects that have attacked them and can fine-tune the defense response accordingly for future attacks.

Given the improvement in knowledge of the mechanisms of plant defense systems, we can embrace the possibility of a “genetic” form of pest control that can help us circumvent the use of chemical pesticides, which, with all their risks, have become a sort of “necessary evil” for farmers. This could usher in modern, scientifically sound ways of organic farming that would free agricultural practices from harmful chemicals.


Explore further How a molecular ‘alarm’ system protects plants from predators


More information: Gen-ichiro Arimura, Making Sense of the Way Plants Sense Herbivores, Trends in Plant Science (2020). DOI: 10.1016/j.tplants.2020.11.001Journal information:Trends in Plant Science Provided by Tokyo University of Science

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Matt Hayes:

‘Researchers help inform cassava breeding worldwide’

“Scientists in Cornell’s NextGen Cassava project have uncovered new details regarding cassava’s genetic architecture that may help breeders more easily pinpoint traits for one of Africa’s most vital crops.

Their findings are reported in a study published July 31 in Plant Molecular Biology.

The scientists analyzed large breeding populations measured extensively over successive years and stages of selection in multi-environment field trials in Nigeria. The genome-wide association analysis explored genomic regions most responsible for desirable traits in cassava, a food crop that provides the main source of calories for 500 million people across the globe.

The scientists found more than 40 quantitative trait loci associated with a total of 14 traits, responsible for characteristics such as disease responses, nutritional quality and yield. The traits were classified broadly into four categories – biotic stress, quality, plant agronomy and agro-morphology.

“Our findings provide critical new entries into the catalogue of major loci available to cassava breeders,” said Ismail Rabbi, a molecular geneticist and plant breeder at the International Institute of Tropical Agriculture (IITA) and a member of the NextGen project. “These markers should greatly improve cassava research and provide another powerful tool for the breeders’ toolbox.”

“Cassava is an incredibly useful food and industrial crop today and will be more so in the future as climate change reshapes agriculture everywhere, but first we must better understand its complex genome,” said Chiedozie Egesi, NextGen program director and co-author on the study.

Based in the Department of Global Development, the NextGen Cassava Breeding project supports scientists from many disciplines with advanced technologies and methods. The project works to empower smallholder cassava farmers in sub-Saharan Africa by developing, releasing and distributing improved cassava varieties.

Plant diseases and pests like cassava mosaic disease (CMD) and cassava green mite are major constraints to cassava production in Africa, India and across Asia, including Vietnam and Thailand. Infections of CMD can lead to yield losses of 82%, or more than 30 million tons each year.

“A complete understanding of cassava’s genetic architecture is the critical step needed to accelerating genetic improvement and bring lasting benefits to farmers and consumers who depend on this crop for food and income throughout the world,” said Egesi, who’s also a visiting scientist in the Department of Global Development and an adjunct professor of plant breeding and genetics in the School of Integrative Plant Science, in the College of Agriculture and Life Sciences.

While the findings revealed novel genomic regions, it also revealed additional markers associated with previously measured traits.

Data from the study was made freely available through several commercial genotyping service vendors. The scientists plan further studies using germplasm from other regions, including East Africa and Latin America, which they say should bolster the catalogue of major effect loci available for molecular breeding.

Study co-authors include Cornell adjunct professor Jean-Luc Jannink and researchers from IITA and the National Root Crops Research Institute in Nigeria. Researchers from the Boyce Thompson Institute and the U.S. Department of Agriculture-Agriculture Research Service also contributed.

NextGen Cassava is funded by the Bill & Melinda Gates Foundation and by UK Aid, a British government initiative.

Matt Hayes is associate director for communications for Global Development in the College of Agriculture and Life Sciences.”

By Matt Hayes for Cornell University

Publication date: Thu 27 Aug 2020

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JULY 20, 2020

Returning to farming’s roots in the battle against the ‘billion-dollar beetle’

by University of Arizona

Returning to farming's roots in the battle against the 'billion-dollar beetle'
Western corn rootworm larvae can devour the tips of corn roots, robbing the plants of nutrients and making them susceptible to falling over. Credit: Cyril Hertz, Lingfei Hu and Matthias Erb, University of Bern, Switzerland

Nicknamed the “billion-dollar beetle” for its enormous economic costs to growers in the United States each year, the western corn rootworm is one of the most devastating pests farmers face.https://3777ec3032f89ac36b1a5fe5c7568749.safeframe.googlesyndication.com/safeframe/1-0-37/html/container.html

“They are quite insidious. They’re in the soil gnawing away at the roots and cutting off the terminal ends of the roots—the lifeblood of corn,” said Bruce Tabashnik, Regents Professor and head of the University of Arizona Department of Entomology. “And if they’re damaging enough, the corn plants actually fall over.”

Genetically modified crops have been an important tool in the battle against pests such as these, increasing yields while reducing farmers’ reliance on broad-spectrum insecticides that can be harmful to people and the environment.

Corn was genetically engineered to produce proteins from the bacterium Bacillus thuringiensis, or Bt, that kill rootworm larvae but are not toxic to humans or wildlife. The technology was introduced in 2003 and has helped keep the corn rootworm at bay, but the pest has begun to evolve resistance.

“So, now the efficacy of this technology is threatened and if farmers were to lose Bt corn, the western corn rootworm would become a billion-dollar pest again,” said Yves Carrière, a professor of entomology in the College of Agriculture and Life Sciences.

Crop Rotation in Mitigating Pest Resistance

Carrière is lead author of a study to be published in PNAS that evaluated the effectiveness of crop rotation in mitigating the damage caused by resistant corn rootworms. Tabashnik and colleagues from North Carolina State University, the University of California-Davis, McGill University and Stockholm University coauthored the study.

Crop rotation, the practice of growing different crops in the same field across seasons, has long been used for pest control. In 2016, the U.S. Environmental Protection Agency mandated crop rotation as a primary means of reducing the damage to Bt corn fields caused by resistant corn rootworms, but there have been limited scientific studies to support the efficacy of this tactic.https://googleads.g.doubleclick.net/pagead/ads?client=ca-pub-0536483524803400&output=html&h=280&slotname=5350699939&adk=2265749427&adf=625945176&w=750&fwrn=4&fwrnh=100&lmt=1595996918&rafmt=1&psa=1&guci=2.2.0.0.2.2.0.0&format=750×280&url=https%3A%2F%2Fphys.org%2Fnews%2F2020-07-farming-roots-billion-dollar-beetle.html&flash=0&fwr=0&rpe=1&resp_fmts=3&wgl=1&dt=1595996918602&bpp=11&bdt=88&idt=147&shv=r20200727&cbv=r20190131&ptt=9&saldr=aa&abxe=1&cookie=ID%3Dfd49ee1f356c7aad-2230268791c20026%3AT%3D1595996908%3AS%3DALNI_MZ__AIkhsEMsw1AjrlZUCXlh_wvFw&correlator=2622896222429&frm=20&pv=2&ga_vid=683244895.1595996911&ga_sid=1595996919&ga_hid=1573871060&ga_fc=0&iag=0&icsg=2271232&dssz=26&mdo=0&mso=0&u_tz=-300&u_his=2&u_java=0&u_h=1080&u_w=1920&u_ah=1040&u_aw=1920&u_cd=24&u_nplug=3&u_nmime=4&adx=447&ady=2184&biw=1903&bih=969&scr_x=0&scr_y=0&oid=3&pvsid=1003068873479674&pem=0&rx=0&eae=0&fc=896&brdim=0%2C0%2C0%2C0%2C1920%2C0%2C1920%2C1040%2C1920%2C969&vis=1&rsz=%7C%7CpeEbr%7C&abl=CS&pfx=0&fu=8320&bc=31&ifi=1&uci=a!1&btvi=1&fsb=1&xpc=7ptrOeJu1R&p=https%3A//phys.org&dtd=154

Carrière and his team rigorously tested this approach by analyzing six years of field data from 25 crop reporting districts in Illinois, Iowa and Minnesota—three states facing some of the most severe rootworm damage to Bt cornfields.

The results show that rotation works. By cycling different types of Bt corn and rotating corn with other crops, farmers greatly reduced rootworm damage.

Most notably, crop rotation was effective even in areas of Illinois and Iowa where rootworm resistance to corn and soybean rotation had been previously reported.

According to the study, crop rotation provides several other benefits as well, including increased yield, reductions in fertilizer use and better pest control across the board.

“Farmers have to diversify their Bt crops and rotate,” Carrière said. “Diversify the landscape and the use of pest control methods. No one technology is the silver bullet.”

Returning to farming's roots in the battle against the 'billion-dollar beetle'
Western corn rootworm beetle on corn tassels. Credit: Joseph L. Spencer, Illinois Natural History Survey, University of Illinois at Urbana-Champaign

A Multipronged Approach

Tabashnik relates the research back to UArizona’s work with the pink bollworm, in which researchers spearheaded a management program to suppress the pink bollworm’s resistance to Bt cotton.

“The key to eradicating pink bollworm in the U.S. was integrating Bt cotton with other control tactics,” Tabashnik said. “We succeeded, whereas this voracious invasive pest rapidly evolved resistance to Bt cotton in India, where the genetically engineered crop was used alone.”

In collaboration with cotton growers, UArizona scientists sustained the efficacy of Bt cotton against pink bollworm by establishing the “refuge strategy,” in which non-Bt crops are planted near Bt crops to allow survival of susceptible insects. The strategy has become the primary approach used worldwide to delay the adaptation of insect pests to genetically engineered crops.

Although farmers have used refuges to thwart the rootworm’s resistance to Bt corn, this strategy alone has proven insufficient against the pest.

“During the last decade, we have learned that refuges are often not sufficient to delay resistance in pests like the corn rootworm,” Carrière said. “It would be wise to diversify management tactics before such pests evolve resistance. This approach, called integrated pest management, is vital for preserving the benefits of biotechnology.”

Returning to Agricultural Roots

In many ways, the study reaffirms traditional agricultural knowledge.

“People have been rotating crops since the dawn of farming. The new agricultural technology we develop can only be sustained if we put it in the context of things we’ve known for thousands of years,” Tabashnik said. “If we just put it out there and forget what we’ve learned in terms of rotating crops, it won’t last.”

The authors emphasize that increasing crop rotation is essential for sustaining the economic and environmental benefits provided by rootworm-active Bt corn. During the six years of the study, the average percentage of corn rotated to other crops per state ranged from about 55-75%.

“This is one of the most important applications of Bt crops in the United States,” Carrière said. “If we lose this technology and we start using soil insecticides again, it’s going to have a big negative environmental impact.”


Explore furtherScientists offer recommendations for delaying resistance to Bt corn in western corn rootworm


More information: Crop rotation mitigates impacts of corn rootworm resistance to transgenic Bt corn, PNAS (2020). DOI: 10.1073/pnas.2003604117Journal information:Proceedings of the National Academy of SciencesProvided by University of Arizona

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Rewiring Plant Defence Genes to Reduce Crop Waste

Article ID: 696239

Released: 18-Jun-2018 12:05 PM EDT

Source Newsroom: University of Warwick

  • Plants could be genetically rewired to better resist disease, helping safeguard crop yields worldwide – new research by the Universities of Warwick and York
  • Defensive feedback control system developed – enables plants to strengthen their defences to withstand attack by re-wiring existing gene connections
  • System uses same approach as aircraft autopilots use to counteract turbulence

Plants can be genetically rewired to resist the devastating effects of disease – significantly reducing crop waste worldwide – according to new research into synthetic biology by the University of Warwick.

Newswise — Led by Professor Declan Bates from the Warwick Integrative Synthetic Biology Centre (WISB) and Professor Katherine Denby from the University of York, who is also an Associate member of WISB, researchers have developed a genetic control system that would enable plants to strengthen their defence response against deadly pathogens – so they could remain healthy and productive.

When pathogens attack crop plants, they obtain energy and nutrients from the plant but also target the plant’s immune response, weakening defence, and making the plants more vulnerable.

Building on experimental data generated by Prof. Denby, Professor Bates’ group simulated a pathogen attack in Arabidopsis plants, and modelled a way to rewire the plants’ gene network, creating a defensive feedback control system to combat disease – which works in much the same way as an aircraft autopilot.

Just as an aircraft’s autopilot control system detects disturbances like wind gusts or turbulence and acts to reject them, this new plant control system detects a pathogen attack, and prevents the pathogen weakening the plants’ defence response.

This method could render crops more resilient against disease, helping mitigate crop wastage throughout the world. Since the system can be implemented by re-wiring plants’ natural defence mechanisms, no external genetic circuitry needs to be added.

Declan Bates, Professor of Bioengineering at the University of Warwick’s School of Engineering, commented:

“Disease, drought and extreme temperatures cause significant yield losses in crop plants all over the globe, threatening world food security. It is therefore crucial to explore new ways to develop crops that are resilient to pathogen attacks and can maintain yields in challenging environments. This study shows the enormous potential of using feedback control to strengthen plants’ natural defence mechanisms.”

Katherine Denby, Professor of Sustainable Crop Production and Director of the N8 AgriFood Resilience Programme at the University of York commented:

“Minimising crop waste is obviously an essential part of creating a more sustainable food system. What is exciting here is applying engineering principles to plant biology to predict how to re-design plant gene regulation to enhance disease resistance. We use re-wiring of existing genes in the plant to prevent pathogen manipulation”

The next steps of the research will be to take the theory into the lab, and experimentally implement the defensive feedback control system in plants.

18 June 2016

Notes to editors:

The research, ‘A Framework for Engineering Stress Resilient Plants Using Genetic Feedback Control and Regulatory Network Rewiring’, is published in ACS Synthetic Biology, a journal of the American Chemical Society.

It is authored by Declan G. Bates, Mathias Foo, Iulia Gherman, Peijun Zhang, and Katherine J. Denby.

 

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Researchers discover wild tomato resistant to a wide range of pests and insects

Scientists at the University of Wageningen (The Netherlands) have discovered a species of wild tomato from the Galapagos Islands that is resistant to a wide range of insect pests. The wild tomato is genetically closely related to the cultivated tomato, which makes it easy to cross-breed it at the agricultural level and make it resistant to different insects.
Cultivated tomatoes are more vulnerable to pests and diseases, since they have lost their natural resistance in the reproduction process. Researchers are working to reverse this by reintroducing the resistance of the wild varieties through breeding, but they still haven’t been able to successfully cross breed the wild tomatoes with the cultivated tomatoes to obtain the necessary traits. The wild tomato of the Galapagos Islands, however, is genetically very similar to the cultivated tomato, and its resistance is encoded within a single chromosome, which should make crossing between the existing plants much easier.
Ben Vosman, a scientist at Wageningen University, said “we work with samples of the wild tomato species Solanum galapagense from a gene bank. The first discovery was that this tomato species is resistant to whiteflies. Then, we discovered it was actually resistant to many other insects as well, including the green peach aphid and the caterpillars of the soldier beetworm. It was a very pleasant surprise.” They have been working on this research since 2010,
“If we can make the cultivated tomatoes resistant to whiteflies, this will directly benefit the environment,” Vosman said. While this problem is still relatively manageable in greenhouses, through integrated control, for example, there are also pests there. In the field crops, the problems with insects are much greater. “We hope that most of the advantages are in the field crops and in the tropics,” he added.
Source: Wageningen University & Research

 

Publication date: 5/3/2018

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