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Archive for the ‘Host plant resistance’ Category

LSU awarded $5 million to look into invasive species harmful to sweet potatoes

A team of LSU AgCenter researchers, collaborating with scientists from four other universities, have been awarded a USDA National Institute of Food and Agriculture grant of more than $5 million, aiding them in developing sweet potato varieties resistant to the invasive guava root-knot nematode.

The AgCenter team is spearheaded by nematologist Tristan Watson. It has also received a sub-grant for $990,000 to support research on sweet potato breeding and characterization of resistance mechanisms and associated genes as well as extension of research findings to regional and national stakeholders.

Watson: “Root-knot nematodes are particularly damaging to the sweet potato. The overall goal of this project is to provide Louisiana sweet potato growers effective tools for the management of established and emerging root-knot nematode species.”

Source: lsuagcenter.com

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Novel Plantibodies show promise to protect citrus from Greening Disease

Citrus greening [huanglongbing (HLB)] has emerged as the most significant disease in citrus (Citrus sp.) agriculture. The disease is associated with the Candidatus Liberibacter species of bacteria. The most prevalent and virulent species in this group is Candidatus Liberibacter asiaticus. It is primarily vectored by the Asian citrus psyllid [ACP (Diaphorina citri)]. 

The bacteria and insect vector are present in many citrus orchards worldwide, including the United States, China, and Brazil. HLB often has a devastating impact on infected citrus; causing a rapid decline, with loss of fruit yield and quality and potentially leading to tree death. The bacteria has had a significant negative impact on the citrus industry, causing loss of fruit quality and yield, as well as loss of root mass, leading to tree decline. Finding a cure has been challenging due to the complexity of the CLas bacteria interactions with the citrus host and the Asian citrus psyllid. Another factor that has made it hard to recover from the disease is the tendency of the citrus industry to focus on a small number of cultivars with commercially desirable traits, but little genetic diversity.

Researchers who are working to find a citrus cultivar that is HLB resistant have a choice of either adding genetic variation through breeding with distant relatives or modifying the trees transgenically. In an article published this month in the Journal of the American Society for Horticultural Science, scientists present promising results from transgenic populations that produce antibodies that can bind with CLas proteins and reduce the bacteria’s ability to replicate. 

This study advances the research needed to test the durability and strength of any resistance conferred by expression in rootstocks to a grafted tree and will hopefully lead to the development of a novel protection strategy for HLB.

According to Ed Stover, a Research Horticulturalist with the USDA Agricultural Research Service, “The Florida citrus industry desperately needs more HLB tolerant trees. If sufficient tolerance can be conferred by a single transgenic rootstock then it will greatly expedite implementation. Any transgenic solution will require extensive validation and analyses for non-target effects and food safety.” 

For more information: doi.org

Publication date: Wed 15 Dec 2021

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“What we saw convinced us again that the ToBRFV resistance is holding very well”

In October 2020, Enza Zaden announced the discovery of the High Resistance gene to ToBRFV. The one and only solution to beat this devastating tomato virus.

Fast forward to today, one year later: what has happened in the past year? Where are we now? And what is yet to come? 

Martijn van Stee, Crop Breeding Manager Tomato, gives an insight into the process to create high-resistant varieties: “Since we discovered the ToBRFV high resistance gene we worked hard on introducing it in our elite parent lines. At this moment we have high-quality parent lines with the ToBRFV resistance. This helps us to make high resistance tomato varieties.”  

Check out the video here.

Trials confirm high resistance 
Besides working on the parent lines, Enza Zaden has done some extensive trials with high resistant varieties in the past year. Martijn: “We trialed the first tomato varieties already in Europe, Mexico, and the Middle East. And what we saw there really convinced us again that the ToBRFV resistance is holding very well.” 

Kees Konst, Crop Research Director, continues: “In the meantime, we started up also the seed production of the hybrids. We already have some examples of high resistance varieties in our hands.” 

Importance of high resistance to ToBRFV 
The gene that Enza Zaden has discovered provides high resistance to ToBRFV. Kees explains the importance of high resistance. “With high resistance, you will not have any problems, because there is no virus in the plant or the fruit. You keep your soil, your water, everything clean.” 

What’s next? 
Eradicating the virus remains our top priority. This is something we can only achieve together with the growers and the fresh produce industry. Martijn: “Our breeders are very busy filling the pipeline. To make more elite parent lines with resistance, to make more varieties with resistance. The solution is right around the corner.”\For more informationEnza Zaden
info@enzazaden.com
www.enzazaden.com

Publication date: Wed 1 Dec 2021

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DECEMBER 1, 2021

Resolute scientific work could eliminate wheat disease within 40 years

by Lauren Quinn, University of Illinois at Urbana-Champaign

wheat
Credit: CC0 Public Domain

Wheat and barley growers know the devastating effects of Fusarium head blight, or scab. The widespread fungal disease contaminates grain with toxins that cause illness in livestock and humans, and can render worthless an entire harvest. As Fusarium epidemics began to worsen across the eastern U.S. in the 1990s and beyond, fewer and fewer farmers were willing to risk planting wheat.

But the battle to eliminate Fusarium head blight never went away. Public breeding programs, with support from the USDA-supported Wheat and Barley Scab Initiative, have been doggedly tweaking soft red winter wheat lines in hopes of achieving greater resistance to the disease.

In a new analysis, University of Illinois researchers say those efforts have paid off. Over the past 20 years, critical resistance metrics have improved significantly. And, they say, if breeding efforts continue, vulnerability to Fusarium head blight could be eliminated within 40 years.

“I don’t think anybody realizes it’s possible we could eliminate Fusarium head blight as a problem. Forty years sounds like a long time, but by the time I’m retired, the threat of disease could be gone. That would make a huge difference,” says Jessica Rutkoski, assistant professor in the Department of Crop Sciences at Illinois and co-author on the new paper.

Rutkoski and her colleagues examined 20 years of data from nine university breeding programs spanning 40 locations in the eastern U.S. That’s a whopping 1,068 wheat genotypes.

In each year and each location, researchers inoculated wheat plants with Fusarium spores. They evaluated both test entries (novel wheat lines) and check cultivars (standard across all locations and years) for various resistance traits. The long-term check cultivars act as a kind of barometer, accounting for agronomic practices and environmental factors.

The researchers looked at disease incidence, severity, Fusarium-damaged kernels, and deoxynivalenol (also known as Vomitoxin) content—the main toxin of concern in Fusarium-contaminated grain. And over 20 years and 1,068 lines, all the resistance traits improved.

“The genetic gain in disease resistance was significant for each of those four traits. Most importantly, we saw a 0.11 parts-per-million decrease in deoxynivalenol per year. Just to see any significant favorable trend is really good,” Rutkoski says. “It basically shows that everyone’s making progress, and that the investment in public breeding programs is paying off.”

Rutkoski says breeders have thrown nearly every technique at wheat to try to improve resistance to Fusarium head blight. It’s a tough nut to crack because resistance is controlled by multiple interacting genes.

“It’s quantitative resistance. There isn’t just one gene that’s going to solve it. On the breeding side, people have looked at exotic sources of resistance, such as Chinese lines that have high resistance. Then they’ll map the genes and introgress them,” Rutkoski says. “That’s been successful to some degree, but those genes tend to be associated with unfavorable traits, like lower yield. So, there have been issues.”

When Rutkoski analyzed the impact of germplasm introductions from Chinese wheat lines, they weren’t responsible for boosting resistance. In other words, progress over the past 20 years was mostly due to breeders exploiting native resistance—the locally adapted wheat‘s inherent genetic capacity to resist disease—rather than introducing resistance from exotic sources.

That’s not to say novel genetic sources of resistance don’t have their place. Rutkoski notes it’s important to try to identify major-effect genes because often they can help breeders achieve their goals faster.

Ultimately, Rutkoski hopes her results justify and encourage investments in public breeding programs.

“Nobody really notices the progress that’s being made. I think there’s some skepticism and suspicion that breeding isn’t that important. Or people think we need to focus more on genome editing or finding more exotic sources of resistance,” she says. “A lot of public breeding programs are getting shut down, and we risk losing all that progress. So, I was gratified to show that the improvement is very consistent over time. And if you just stick to this kind of strategy, you will have guaranteed results. It’s not risky.”

The article is published in Plant Disease.


Explore furtherScientists discover a protein that naturally enhances wheat resistance to head scab


More information: Rupesh Gaire et al, Genetic trends in Fusarium head blight resistance due to 20 years of winter wheat breeding and cooperative testing in the Northern US., Plant Disease (2021). DOI: 10.1094/PDIS-04-21-0891-SRProvided by University of Illinois at Urbana-Champaign

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DECEMBER 1, 2021

Resolute scientific work could eliminate wheat disease within 40 years

by Lauren Quinn, University of Illinois at Urbana-Champaign

wheat
Credit: CC0 Public Domain

Wheat and barley growers know the devastating effects of Fusarium head blight, or scab. The widespread fungal disease contaminates grain with toxins that cause illness in livestock and humans, and can render worthless an entire harvest. As Fusarium epidemics began to worsen across the eastern U.S. in the 1990s and beyond, fewer and fewer farmers were willing to risk planting wheat.

But the battle to eliminate Fusarium head blight never went away. Public breeding programs, with support from the USDA-supported Wheat and Barley Scab Initiative, have been doggedly tweaking soft red winter wheat lines in hopes of achieving greater resistance to the disease.

In a new analysis, University of Illinois researchers say those efforts have paid off. Over the past 20 years, critical resistance metrics have improved significantly. And, they say, if breeding efforts continue, vulnerability to Fusarium head blight could be eliminated within 40 years.

“I don’t think anybody realizes it’s possible we could eliminate Fusarium head blight as a problem. Forty years sounds like a long time, but by the time I’m retired, the threat of disease could be gone. That would make a huge difference,” says Jessica Rutkoski, assistant professor in the Department of Crop Sciences at Illinois and co-author on the new paper.

Rutkoski and her colleagues examined 20 years of data from nine university breeding programs spanning 40 locations in the eastern U.S. That’s a whopping 1,068 wheat genotypes.

In each year and each location, researchers inoculated wheat plants with Fusarium spores. They evaluated both test entries (novel wheat lines) and check cultivars (standard across all locations and years) for various resistance traits. The long-term check cultivars act as a kind of barometer, accounting for agronomic practices and environmental factors.

The researchers looked at disease incidence, severity, Fusarium-damaged kernels, and deoxynivalenol (also known as Vomitoxin) content—the main toxin of concern in Fusarium-contaminated grain. And over 20 years and 1,068 lines, all the resistance traits improved.

“The genetic gain in disease resistance was significant for each of those four traits. Most importantly, we saw a 0.11 parts-per-million decrease in deoxynivalenol per year. Just to see any significant favorable trend is really good,” Rutkoski says. “It basically shows that everyone’s making progress, and that the investment in public breeding programs is paying off.”

Rutkoski says breeders have thrown nearly every technique at wheat to try to improve resistance to Fusarium head blight. It’s a tough nut to crack because resistance is controlled by multiple interacting genes.

“It’s quantitative resistance. There isn’t just one gene that’s going to solve it. On the breeding side, people have looked at exotic sources of resistance, such as Chinese lines that have high resistance. Then they’ll map the genes and introgress them,” Rutkoski says. “That’s been successful to some degree, but those genes tend to be associated with unfavorable traits, like lower yield. So, there have been issues.”

When Rutkoski analyzed the impact of germplasm introductions from Chinese wheat lines, they weren’t responsible for boosting resistance. In other words, progress over the past 20 years was mostly due to breeders exploiting native resistance—the locally adapted wheat‘s inherent genetic capacity to resist disease—rather than introducing resistance from exotic sources.

That’s not to say novel genetic sources of resistance don’t have their place. Rutkoski notes it’s important to try to identify major-effect genes because often they can help breeders achieve their goals faster.

Ultimately, Rutkoski hopes her results justify and encourage investments in public breeding programs.

“Nobody really notices the progress that’s being made. I think there’s some skepticism and suspicion that breeding isn’t that important. Or people think we need to focus more on genome editing or finding more exotic sources of resistance,” she says. “A lot of public breeding programs are getting shut down, and we risk losing all that progress. So, I was gratified to show that the improvement is very consistent over time. And if you just stick to this kind of strategy, you will have guaranteed results. It’s not risky.”

The article is published in Plant Disease.


Explore furtherScientists discover a protein that naturally enhances wheat resistance to head scab


More information: Rupesh Gaire et al, Genetic trends in Fusarium head blight resistance due to 20 years of winter wheat breeding and cooperative testing in the Northern US., Plant Disease (2021). DOI: 10.1094/PDIS-04-21-0891-SRProvided by University of Illinois at Urbana-Champaign

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SCN: What you can do to fight soybeans’ top yield robber

DFP Staffsoybean fieldRotating SCN-resistant sources of resistance is an active management strategy advised by the SCN Coalition, but easier said than done for Midsouth growers.”We’re seeing bushels upon bushels of soybeans lost.”

Ginger Rowsey | Dec 02, 2021

Soybean cyst nematode continues to rank as the top yield robber of soybeans in the U.S. and Canada and it’s showing no signs of stopping. Since 2017 SCN has continued to move into new areas, and, according to experts is becoming harder to control. 

“We’re seeing bushels upon bushels of soybeans lost. The biggest challenge is yield loss can occur in the absence of symptoms. We’ve observed yield loss of up to 30% in fields that looked fine,” said Kaitlyn Bissonnette, Extension specialist with the University of Missouri. Bissonnette was speaking at a Grow in the Know SCN webinar, sponsored by the SCN Coalition and BASF. https://31ff83a5596d5b2313020cd4368ba0f3.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html

In addition to SCN expanding to new geographic areas, there is evidence these nematodes are also adapting to PI 88788 — the most common source of SCN resistance that is available in about 95% of SCN-resistant varieties. In Tennessee, for example, the SCN Coalition reports that 93% of fields planted to soybean varieties with PI 88788 sources of resistance have seen SCN numbers increase more than 10%. 

“This elevated reproduction tells us these sources are no longer as resistant as they once were,” said Bissonnette. 

Rotating sources of resistance 

Rotating sources of resistance would slow SCN’s growing tolerance to one source. The problem for Midsouth growers is there are few desirable alternatives to PI 88788. Peking is the second most widely used source of SCN resistance, but it is not a major player in southern soybean genetics. A search of seed companies’ websites revealed Peking resistance could only be found commercially available in maturity groups earlier than MG3.  

Expanding the sources of SCN resistance is not an easy task. Public soybean breeders have spent years working with SCN resistance breeding lines other than PI 88788. Unfortunately, breeding resistance genes from those other sources — such as Peking and Hartwig — into elite varieties has been challenging. 

Vince Pantalone, soybean breeder with the University of Tennessee said Hartwig resistance is the better option for the South. This year, UT’s breeding program released TN14-5021, which Pantalone says contains multiple SCN resistance as well as resistance to many southern plant pathogens. Other universities, such as University of Illinois and University of Nebraska have also developed cultivars with the Hartwig resistance source. 

If growers can only get soybeans with PI 88788 resistance, the SCN Coalition recommends rotating different varieties of soybeans with PI 88788 because not all PI 88788 varieties are the same. 

“Ideally, we’d like growers to rotate among several different modes of action of SCN resistance,” said Melissa Mitchum, University of Georgia molecular nematologist. “That’s what we’re working to provide.”  

More resistance genes on the way 

However, Mitchum says there are additional resistance genes that haven’t been used yet in commercial soybean varieties. “We’ve only utilized Rhg1 and Rhg4, and that’s what you see in growers’ fields, but we can breed with other sources to introduce other resistance genes.” 

Mitchum is working closely with soybean breeders to investigate other sources of resistance. “We’ve already found new genes and gene combinations that are different from Rhg1b in PI 88788 and the Rhg1a/Rhg4 combination in Peking to help fight back against virulent SCN.”  

SCN research 

For several years, checkoff-funded researchers have been working to identify novel types of nematode resistance. Advances in technology, such as the ability to clone resistance genes and the development of precise molecular markers, have allowed university soybean breeders to speed up the process of getting resistant cultivars out to commercial breeders.   

“Today, we can quickly test more soybean germplasm for nematode resistance,” Mitchum explains. “We’re also looking at which genes we should combine, which genes we shouldn’t, and the best rotation strategies for different modes of action.”   

The goal is to get more SCN-resistant modes of action on the market for farmers and protect existing SCNresistance sources. “We want to keep PI 88788 in the toolbox and offer growers other options to protect their soybean yields,” Mitchum says.  

Beyond variety selection 

Beyond variety selection, crop rotation is still effective within reason, according to Bissonnette.  

“We can’t get rid of this through crop rotation alone, but cultural practices like that along with planting certain species of cover crops and improving weed management can help,” she said.  

“Growers could also consider using SCN seed treatments, especially where SCN populations have gotten out of control,” she added. Results from an SCN Coaltion survey showed the number of growers using nematode protectant seed treatments has almost doubled over the past five years. 

“Soil testing will always be the first step in SCN management. Those results will give you a better idea of how intensively to manage, but it’s much easier to keep counts down than reduce high numbers,” Bissonnette said. “The most important steps will be selecting resistant varieties and using different resistance sources. If that’s not an option for you, at least rotate varieties within PI 88788.”  

Learn more 

To learn more about the checkoff-funded research that’s focused on bringing new tools to soybean growers in the fight against parasitic nematodes, watch the Research Collection of “Let’s Talk Todes” videos. 

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Over half of winter wheat varieties resistant to yellow rust at the young-plant stage

02 Dec 2021 ShareCategories: Agronomy / Arable

Farming Online

The UK Cereal Pathogen Virulence Survey (UKCPVS) has released its annual update on the varietal resistance of young winter wheat plants to yellow rust.

Conducted on AHDB Recommended Lists (RL) varieties, including candidates, the latest screens found that over half of the varieties tested were resistant at the young-plant stage.

A young pot-grown wheat plant showing severe yellow rust symptoms.

Growers should use the information, alongside the RL (adult plant) disease resistance ratings, to adapt spray programmes in 2022, particularly at the T0 spray timing.

Dr Charlotte Nellist, UKCPVS project lead at NIAB, said: “The pathogen that causes yellow rust is complex; some varieties are susceptible to the disease when plants are young but go on to develop some level of resistance after early stem extension. However, if young plants are susceptible and the RL disease resistance rating is also low, crops will require closer monitoring for active rust over the winter period.”

The screens use five pathogen isolates selected by UKCPVS to best represent the diversity in the yellow rust population at the time of testing. A variety is classified as susceptible at the young-plant stage if it is sufficiently susceptible to any one of the isolates.

Charlotte said: “The 2010s saw large changes in the UK yellow rust population, resulting in numerous reductions in resistance, at both the young-plant and adult-plant stages. For example, only three varieties were recorded as having young-plant stage resistance in 2016. Since then, the situation has improved somewhat, with over half of the varieties screened in 2021 classed as resistant during these early growth stages.” 

Relatively few yellow rust samples were received by the UKCPVS team in 2021, with 155 samples sent in (from 54 varieties and 19 counties) – around half the number recorded in 2020. The reduction is probably due to this year’s cool, dry spring, which helped reduce wheat yellow rust pressure. Similarly, for brown rust, only 10 samples were received.

Charlotte said: “It is important to send in material, irrespective of the disease pressure. It helps us provide a regional snapshot of the pathogen population and serves as a basis for early warnings of population change. While we cannot test every sample, we do preserve and archive all isolates, which provides an essential reference library for pathogen virulence research.”

The latest cereal pathogen developments, both in the UK and globally, will be in focus at the annual UKCPVS stakeholder meeting on 2 March 2022.

UKCPVS thanks everyone who submitted samples and looks forward to continued support in 2022.

For further information, including about the event and sampling instructions, visit: ahdb.org.uk/ukcpvs

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IAPPS Region X Northeast Asia Regional Center (NEARC)

Present committee members

Dr. Izuru Yamamoto, Senior Advisor

Dr. Noriharu Umetsu, Senior Advisor

Dr. Tsutomu Arie, a representative of the Phytopathological Society of Japan, the chair of Region X

Dr. Tarô Adati, a representative of Japanese Society of Applied Entomology and Zoology

Dr. Hiromitsu Moriyama, a representative of Pesticide Science Society of Japan, the secretary general of Region X

Dr. Rie Miyaura, a representative of The Weed Science Society of Japan

The Phytopathological Society of Japan and Pesticide Science Society of Japan became official partners of IYPH2020 by FAO of UN and Ministry of Agriculture, Forestry and Fisheries (MAFF) of Japan and endeavored to educate the society on plant protection. https://www.maff.go.jp/j/syouan/syokubo/keneki/iyph/iyph_os.html

Annual activities related to IAPPS especially to IPM of plant diseases, insects and weeds, and plant regulation (from April 2020 to March 2021)

The Phytopathological Society of Japan (PSJ)

2020 Kanto District Meeting, Online; Sep 21–22, 2020

2020 Kansai District Meeting, Online; Sep 21–22, 2020

2020 Tohoku District Meeting, Online; Oct 12–14, 2020

2020 Hokkaido District Meeting, Online; Oct 15, 2020

2020 Kyushu District Meeting, Online; Nov 24–26, 2020

2021 Annual Meeting, Online; Mar 17–19, 2021

Japanese Society of Applied Entomology and Zoology (JSAEZ)

65th Annual Meeting, online, March 23-26, 2021

28th Annual Research Meeting of the Japan-ICIPE Association, online, March 25, 2021

Pesticide Science Society of Japan

37rd Study Group Meeting of Special Committee on Bioactivity of Pesticides, online, Sep 18, 2020

40th Symposium of Special Committee on Agricultural Formulation and Application, Yokohama, Kanagawa; Oct 15–16, 2020 (Cancelled due to the spread of COVID-19)

43th Annual Meeting of Special Committee on Pesticide Residue Analysis, online, Nov. 5–6, 2020

46th Annual meeting, Fuchu, Tokyo and Online, March 8–10, 2021

The Weed Science Society of Japan (WSSJ)

2020 Annual Meeting, The Weed Science Society of Kinki, Online; Dec 5, 2020

35th Symposium of Weed Science Society of Japan, Online; Dec 12, 2020

2020 Annual Meeting, Kanto Weed Science Society, Online; Dec 22, 2020

22th Annual Meeting, The Weed Science Society of Tohoku, Japan, Online; Feb 25, 2021

2020 Study Group Meeting of Weed Utilization and Management in Small Scale Farming, Online; Feb 26, 2021

Hono-Kai (means, Meeting who are appreciating agriculture)

35th Hono-Kai Symposium was cancelled due to the epidemic of COVID-19

Japan Biostimulants Association

rd Symposium, Online; Nov 2–30, 2020

Nodai Research Institute

2020-1 Biological Control Group Seminar, Setagaya; Tokyo; Jun 16, 2020 (Cancelled due to the epidemic of COVID-19)

2020-2 Biological Control Group Seminar, online, Nov 13, 2020

2021-1 Biological Control Group Seminar, online, Jun 15, 2021

2021-2 Biological Control Group Seminar, online, Nov 9, 2021

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Studying plants’ protective hair

by Michigan State University

Studying plants’ protective hair
Yann-Ru Lou and Thilani Anthony collaborate to study how black nightshade (Solanum nigrum) makes a large number of distinct types of sticky acylsugars. Credit: Jeff Mason

Plants are master chemists, producing a dazzling array of molecules that are valuable to humans, including vitamins, pharmaceuticals and flavorings.

The largest and most diverse group of molecules are known as specialized metabolites. Some metabolites attract beneficial insects and others repel or kill herbivore insects that feed on plants or pathogenic microbes. Some of these metabolites are poised for action at the surface of the plant, being made in trichomes, which are small hairs on stems, leaves and flowers. Unfortunately, these natural defenses are often missing from crop plants, having been lost during domestication or advanced breeding.

For example, nightshade family (Solanaceae) plants synthesize sugar esters (acylsugars), which have anti-fungal and anti-herbivory activities. In species that accumulate and secrete large quantities, their sticky nature provides physical defenses as ‘glue’ adhering insect pest mouths and ‘flypaper’ entrapment of small-bodied insects.

However, cultivated tomato (Solanum lycopersicum) accumulates a relatively small amount of these acylsugars, and are undetectable on some other economically important Solanaceous crops, such as sweet pepper. Understanding how these missing metabolites are made in wild relatives can suggest breeding approaches to make crops more resilient to pests without use of chemical pesticides.

In a paper published in Science Advances, a team of MSU scientists from the Michigan State University College of Natural Science followed up on their observation that the common black nightshade (Solanum nigrum) makes an unusually large number of different acylsugar protective compounds in their trichome hairs. The study took place in the laboratories of Biochemistry and Molecular Biology (BMB) University Distinguished Professor and Barnett Rosenberg Professor Rob Last, and MSU Mass Spectrometry Facility Director and BMB Professor Dan Jones.

“Because black nightshade makes so many acylsugars, we developed an accelerated acylsugar structure elucidation pipeline to speed up our study,” said Yann-Ru Lou, BMB postdoctoral researcher in the Last lab, and first author of the study. “We obtained structural information critical for enzymology without the time- and labor-consuming metabolite purification step by combining cutting edge analytical chemistry methods available at MSU.”

A surprise from this study is that black nightshade acylsugars have distinct types of compounds not found together in other plants: acylglucoses and acylinositols. These are based on the sugar glucose and vitamin-like substance inositol. Understanding how the wild species makes these two classes of protective molecules could lead to breeding of crops that can grow without synthetic pesticides.

“An exciting outcome of this work is the discovery of a novel type of invertase, the enzyme we normally think of being made by bees to produce honey and by yeast for fermentation,” Last said. This invertase evolved to be made in the trichome hairs and synthesize acylglucose, rather than the sweet glucose found in honey. The results illustrate the remarkable metabolic diversity found in flowering plants.”


Explore furtherScientists discover ancient enzymes evolve new tricks


More information: Yann-Ru Lou et al, It happened again: Convergent evolution of acylglucose specialized metabolism in black nightshade and wild tomato, Science Advances (2021). DOI: 10.1126/sciadv.abj8726Journal information:Science AdvancesProvided by Michigan State University26 shares

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Tar spot gains attention of USDA-ARS

Tom J. Bechmancorn leaf with signs of tar spotEARLY STAGES: Agronomists say growers need to learn to identify tar spot at this stage. This specimen was growing in Bayer’s fungicide demonstration plots at the Farm Progress Show.Hi-Tech Farming: The newest corn disease in the U.S. is targeted by researchers.

Tom J Bechman | Nov 18, 2021

Tar spot was first detected in the U.S. in 2015, but it now has the undivided attention of a USDA Agricultural Research Service research team based in West Lafayette, Ind. Growers fight this corn disease with fungicides. However, Steve Goodwin, an ARS plant pathologist, says plants that have resistance to tar spot are preferable.

While participating universities conduct research on timing of fungicides and other control measures, Goodwin and his team are concentrating on four fronts:

1. Screening current material. The team is screening existing commercial varieties and germplasm lines for resistance or susceptibility to tar spot. The goal is to help growers adjust management practices as soon as possible depending upon which hybrids they grow.

2. Developing molecular markers. These tools will identify Qrtsc8, the gene that confers tar spot resistance. Investigators are also exploring why some plants that lack this gene are still resistant, since an unknown gene or genes could be involved.

3. Determining biocontrol potential. A microbiome of organisms was found on tar spot-resistant plants, but not on susceptible plants. Researchers want to know how these organisms, plant growth stage and the environment are interconnected in the progression of tar spot.

4. Understanding how tar spot works. Scientists also want to learn how the tar spot fungus uses several proteins to short-circuit defenses of susceptible plants. Identification of these proteins could lead to better detection of different strains of the fungus and its severity in the field.

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Ancestor’s microbiome may help corn resist insect pests

Texas A&M AgriLife scientists study how teosinte’s microbes could help with insect control in corn

NOVEMBER 2, 2021

Texas A&M AgriLife scientists are working to enhance corn’s resistance to insects such as fall armyworm by transplanting beneficial microbes found in corn’s resilient ancestor, teosinte.

green plant stalk and leaves
An early reproductive stage teosinte plant showing silk from an ear. (Texas A&M AgriLife photo by Julio Bernal)

The work is urgently needed because fall armyworm, western corn rootworm and other insects are becoming increasingly impervious to existing control methods. Corn is among the most planted and essential crops around the world. In the U.S. alone, western corn rootworm causes more than $1 billion in damage to corn crops each year. Insects’ resistance to pesticides can lead to ramped-up pesticide use, which can create environmental problems.

By focusing on beneficial microbes from teosinte, the Texas A&M AgriLife research team aims to create an environmentally friendly insect control method specifically suited to corn.

The research was funded this summer by a $199,892 grant from the U.S. Department of Agriculture National Institute of Food and Agriculture. The grant builds on a seed grant from the Collaborative Research Grant Program of Texas A&M University and the Consejo Nacional de Ciencia y Tecnología, a Mexican government agency.

Leading the project is Julio Bernal, Ph.D., professor, Texas A&M College of Agriculture and Life Sciences Department of Entomology. Bernal is collaborating with Sanjay Antony-Babu, Ph.D., an AgriLife Research assistant professor with the Department of Plant Pathology and Microbiology, and Thomas Isakeit, Ph.D., professor and Texas A&M AgriLife Extension Service specialist, also with the Department of Plant Pathology and Microbiology.

Clues to insect control

A series of clues over the past decade gave the team the idea for the project. Bernal’s previous work, and that of others, demonstrated that teosinte is much less hospitable to insect pests than corn is. Meanwhile, studies also showed that the microbiome of corn, or maize, has changed greatly over the past century, diverging from that of teosinte. However, practically all the studies to date have focused on microbes living on and around the roots of corn and teosinte — the rhizosphere. In contrast, few studies have focused on microbes living inside corn tissues, especially in the leaves, Bernal said.

“Studies have shown that the rhizosphere does, in fact, affect insect resistance in maize and can improve it,” Bernal said. “But no one had looked at the microbiome inside maize tissues. We began looking into that.”

If teosinte’s microbiome holds answers for insect resistance in corn, seeking those answers in teosinte’s internal microbiome has several advantages to looking toward root surfaces or the soil. Teosinte’s internal microbiome must be compatible with the plant’s innate immune system. Hence, this microbial community is less likely to contain pathogens and more likely to contain species that would thrive in corn and benefit the crop.

Preliminary effects on growth, insect resistance

At the end of a growing season, the team collected dead teosinte leaves. The researchers then added those leaves to the soil where they grew maize seedlings.

“We saw effects on growth and insect resistance,” Bernal said.

In corn seedlings grown in soil treated with teosinte leaves, “resistance was much better towards the fall armyworm. This was very exciting because this was a very simple experiment, not sophisticated at all.”

A surprising snag

Next, the team worked to establish whether the leaves’ internal microbes, rather than those on the leaves, were indeed a key factor in resistance to fall armyworm.

two black seedling boxes with six taller plants on the left side and six smaller plants on the right side - these are corn seedlings.
Corn seedlings treated and untreated with teosinte leaf microbiome inoculant. (Texas A&M AgriLife photo provided by Julio Bernal)

Antony-Babu separated the bacteria from green teosinte leaves and applied the microbes to corn seeds. Bernal’s team then grew the seeds into seedlings.

“We ran the experiment, and it gave us totally different results than before,” Bernal said.

Antony-Babu suggested that both fungi and bacteria from the teosinte microbiome may take part in enhancing insect resistance. So, a fungal-bacterial mixture was applied to the corn seeds next. Now, the seedlings indeed grew better and had better insect resistance than the controls.

“Maybe there are some fungi that belong there,” Bernal said.

Next steps for insect control

Over the next three years, the team plans to refine the method and make it more reliable. The researchers will optimize the culturing techniques and the way they apply the treatment to the corn seeds. They will also look for effects against important pests other than fall armyworm, such as western corn rootworm.

Next, the team will identify the species making up the microbiome and determine a combination of species that are key for insect resistance.

“Maybe only 10 of the species create the effect,” Bernal said. “Once we know what species make it work, we can create the treatment from cultures in the lab. We wouldn’t have to go back every time to teosinte leaves.”

The study’s third year will include growing a small set of treated crops in the field as proof of concept.

“Commercialization is the obvious endpoint,” Bernal said.

If the team’s efforts eventually lead to a commercial product, pests would be less likely to evolve resistance to this mixture of microbes than to a single chemical treatment. And, corn producers would obtain an alternative, eco-friendly treatment against insects.

-30-MEDIA INQUIRIESLaura Muntean
laura.muntean@ag.tamu.edu
6012481891

Olga Kuchment510.847.7204Olga.Kuchment@ag.tamu.eduOlga Kuchment is a communication specialist for Texas A&M AgriLife Communications in College Station. She is responsible for writing news releases and feature articles from science-based information generated or provided by AgriLife faculty throughout the state.

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