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Archive for the ‘Fungi’ Category

From PestNet

penn state

UNIVERSITY PARK, Pa. — Use of the powerful gene-editing tool CRISPR-Cas9 could help to breed cacao trees that exhibit desirable traits such as enhanced resistance to diseases, according to Penn State plant scientists.

The cacao tree, which grows in tropical regions, produces the cocoa beans that are the raw material of chocolate. Reliable productivity from cacao plants is essential to the multibillion-dollar chocolate industry, the economies of producing countries and the livelihoods of millions of smallholder cacao farmers.

But each year, several plant diseases severely limit global production, with 20-30 percent of cocoa pods destroyed preharvest, noted lead author Andrew Fister, postdoctoral scholar in plant science, College of Agricultural Sciences, Penn State.

“In West Africa, severe outbreaks of fungal diseases can destroy all cacao fruit on a single farm,” said Fister. “Because diseases are a persistent problem for cacao, improving disease resistance has been a priority for researchers. But development of disease-resistant varieties has been slowed by the need for sources of genetic resistance and the long generation time of cacao trees.”

The researchers reported recently, in Frontiers in Plant Science, the study results, which were thought to be the first to demonstrate the feasibility of using cutting-edge CRISPR technology to improve Theobroma cacao.

CRISPR stands for clustered regularly interspaced short palindromic repeats. It is a way to modify an organism’s genome by precisely delivering a DNA-cutting enzyme, Cas9, to a targeted region of DNA. The resulting change can delete or replace specific DNA pieces, thereby promoting or disabling certain traits.

Previous work in cacao identified a gene, known as TcNPR3, that suppresses the plant’s disease response. The researchers hypothesized that using CRISPR-Cas9 to knock out this gene would result in enhanced disease resistance.

Andrew Fister with cacao trees

Andrew Fister, postdoctoral scholar in plant science, stands among cacao trees in the African country of Ivory Coast. Pods turning yellow and black are infected with black pod disease.

Image: Désiré Pokou

 

To test their hypothesis, they used Agrobacterium — a plant pathogen modified to remove its ability to cause disease — to introduce CRISPR-Cas9 components into detached cacao leaves. Subsequent analysis of treated tissue found deletions in 27 percent of TcNPR3 copies.

When infected with Phytopthera tropicalis, a naturally occurring pathogen of cacao and other plants, the treated leaves showed greater resistance to the disease. The results suggested that the mutation of only a fraction of the copies of the targeted gene may be sufficient to trigger downstream processes, resulting in systemic disease resistance in the plant.

The researchers also created CRISPR gene-edited cacao embryos, which they will grow into mature trees to test the effectiveness of this approach at a whole-plant level.

This research builds on more than 30 years of biotechnology research aimed at building a better cacao tree, according to senior author Mark Guiltinan, professor of plant molecular biology and leader of Penn State’s endowed cocoa research program.

“Our lab has developed several tools for the improvement of cacao, and CRISPR is just one more tool,” he said. “But compared to conventional breeding and other techniques, CRISPR speeds up the process and is much more precise. It’s amazingly efficient in targeting the DNA you want, and so far, we haven’t detected any off-target effects.”

In addition to providing a new tool to accelerate breeding, CRISPR-Cas9 technology can help deliver insights into basic biology by offering a method to efficiently assess gene function, the researchers said.

“With CRISPR, we can quickly ‘break’ a gene and see what happens to the plant,” Guiltinan explained. “We have a list of genes in the pipeline that we want to test.”

There may be thousands of genes involved in disease resistance, Fister added.

“We want to evaluate as many as we can,” he said.

The ultimate goals of Penn State cacao research are to help raise the standard of living for smallholder growers and stabilize a threatened cocoa supply by developing plants that can withstand diseases, climate change and other challenges, according to co-author Siela Maximova, senior scientist and professor of horticulture.

“Any production increases in the last 20 years have been mostly due to putting more land into production,” said Maximova, who co-directs the cacao research program. “But land, water, fertilizer and other inputs are limited. To enhance sustainability, we need plants that are more vigorous and disease resistant and that produce more and better-quality beans.

“This study provides a ‘proof of concept’ that CRISPR-Cas9 technology can be a valuable tool in the effort to achieve these goals,” she said.

Lena Landherr Sheaffer, research assistant in plant science, Penn State, also was a co-author on the paper.

This work was supported by the Penn State College of Agricultural Sciences, the Huck Institutes of the Life Sciences, the Penn State Endowed Program in the Molecular Biology of Cacao, the National Science Foundation and the U.S. Department of Agriculture’s National Institute of Food and Agriculture.

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Study could spawn better ways to combat crop-killing fungus

Rutgers-led genome research finds fungus that causes disease in rice became harmful 21 million years ago

Rutgers University

IMAGE
IMAGE: Ning Zhang, associate professor in the Department of Plant Biology and the Department of Biochemistry and Microbiology at Rutgers University-New Brunswick, holds a Petri dish with switchgrass seedlings inoculated with… view more 

Credit: Nick Romanenko/Rutgers University

About 21 million years ago, a fungus that causes a devastating disease in rice first became harmful to the food that nourishes roughly half the world’s population, according to an international study led by Rutgers University-New Brunswick scientists.

The findings may help lead to different ways to fight or prevent crop and plant diseases, such as new fungicides and more effective quarantines.

Rice blast, the staple’s most damaging fungal disease, destroys enough rice to feed 60 million people annually. Related fungal pathogens (disease-causing microorganisms) also infect turfgrasses, causing summer patch and gray leaf spot that damage lawns and golf courses in New Jersey and elsewhere every summer. And now a new fungal disease found in wheat in Brazil has spread to other South American countries.

Results from the study published online in Scientific Reports may lead to better plant protection and enhanced national quarantine policies, said Ning Zhang, study lead author and associate professor in the Department of Plant Biology and the Department of Biochemistry and Microbiology in the School of Environmental and Biological Sciences.

“The rice blast fungus has gotten a lot of attention in the past several decades but related species of fungi draw little attention, largely because they’re not as severe or not harmful,” Zhang said. “But they’re all genetically related and the relatives of severe pathogens have been little-studied. You have to know your relatives to have a holistic understanding of how the rice blast pathogen became strong and others did not.”

The study is the outcome of a 2016 international symposium at Rutgers-New Brunswick hosted by Zhang and Debashish Bhattacharya, study senior author and distinguished professor in the Department of Biochemistry and Microbiology. The National Science Foundation, Rutgers Center for Turfgrass Science, and School of Environmental and Biological Sciences funded the symposium by researchers from the U.S., France and South Korea.

The scientists studied Magnaporthales, an order of about 200 species of fungi, and some of the new members were discovered in the New Jersey Pine Barrens. About half of them are important plant pathogens like the rice blast fungus – ranked the top fungal pathogen out of hundreds of thousands. After the first sign of infection, a rice field may be destroyed within days, Zhang said.

To get a holistic understanding of how the rice blast fungus evolved, scientists genetically sequenced 21 related species that are less harmful or nonpathogenic. They found that proteins (called secretomes) that fungi secrete are especially abundant in important pathogens like the rice blast fungus.

Based on previous research, the proteins perhaps became more abundant over time, allowing the fungi to infect crops, Zhang said. The researchers identified a list of genes that are abundant in pathogens but less so in nonpathogens, so the abundant genes might promote pathogens that can infect crops. The results will allow scientists to look into the mechanism behind the infection process.

“With climate change, I think the rice blast problem can only get worse because this is a summer disease in warm climates where rice is grown,” Zhang said, adding that wheat, turfgrass and other important plants may also be affected.

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Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

 

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Bangladesh: Rice blast

unb

Rice blast hits Boro corps in Sirajganj

UNB NEWS

Wednesday 18 April, 2018 12:38:55 pm

Rice blast hits Boro corps in Sirajganj

Sirajganj, Apr 18 (UNB) – Farmers of nine upazilas in the district are worried of getting poor yield of Boro crops due to fungal disease blast attack during the harvesting season.

The fungal attack has spread all over the upazilas, according to sources at the Department of Agricultural Extension (DAE) department.

Some 20,000 hectares of land have been affected by the fungal disease in the last three days. The worst affected areas are: Sadar, Raiganj, Chouhali, Ullapara, Belkuchi and Kamarkhand upazilas of the district.

In an instant measure, the DAE authorities cancelled the leave of all employees and staffs in effected upazilas for bringing the situation under control as well as to protect the paddy field from the attack, said Agriculturist Arshed Ali, deputy director of DAE.

The DAE sources said the blast disease affected the paddy fields as farmers did not put fertiliser in a proper way. Besides, the hot temperature in daylight and fall of the same in night has pushed up the epidemic.

Due to the fungal infection, the plants became white in colour, Agriculturist Arshed Ali told UNB.

He advised the farmers to spray medicines on the paddy field to protect the corps.

Some 1.40 lakh hectares of land in the area have been brought under Boro cultivation this year.

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fresh plaza logo

Path of Panama disease fungus established for the first time

The much-feared Tropical Race 4 strain of the Fusarium oxysporum soil fungus which causes Panama disease in Cavendish bananas has now been discovered in Myanmar. This follows closely on the heels of its discovery in Vietnam and Laos. The fungus is expected to have disastrous consequences on individual banana growers and the global banana industry. Scientists from Wageningen University & Research working with colleagues abroad have detected the fungus and used advanced techniques to find out where it came from.

Panama disease is a form of Fusarium wilt, caused by Fusarium oxysporum. The strain of this fungus known as Tropical Race 4 (TR4) affects many local banana varieties as well as the Cavendish cultivar, which accounts for 85% of world trade in bananas. Since all Cavendish bananas are clones of each other and there is little variation, they are highly susceptible to TR4, making the sector extremely vulnerable.

As explained on phys.org, the fungus, which appeared several decades ago, infects the roots, attacks the vascular system and eventually kills the plant. Once a plot is infected, bananas can no longer be cultivated there. This is a major threat to the global monoculture of Cavendish bananas.

TR4 has now been detected in Myanmar for the first time and its presence in Vietnam and Laos has been confirmed. In addition, research has made it possible to see which path it took to get there. There are links between the strains found in TR4 in China and these countries and in Pakistan and the Philippines, and between those detected in Lebanon and Jordan.

After sampling missions, the fungus was isolated from infected plants and then further studied by means of DNA testing. By determining the number and nature of mutations in the fungus, scientists were able to see exactly which strains are related. “This has reaffirmed the need for quarantine measures to prevent international spread and the need for sustainable solutions,” states Gert Kema, professor by special appointment of tropical phytopathology at Wageningen University & Research.

Publication date: 4/26/2018

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Radio New Zealand

29 Mar 2018

Onion crop slashed by disease

6:30 pm on 29 March 2018

The country’s onion crop has been slashed by at least 20 percent because of humid weather which resulted in a leaf disease.

Onions

Photo: RNZ/Carol Stiles

The harvest period is wrapping up for the season, and Onions New Zealand chief executive Michael Ahern said it had been a mixed bag for growers.

The main problem was a leaf blight called ‘Stemphylium’ which has damaged the plants, he said.

No caption

Michael Ahern Photo: Supplied

 

“We’ve had some difficulties in a number of the growing areas … to that end we ran a crop forecast survey recently and we could be down by around 20 percent on yield … even that could be increased by quality issues at packing time.”

The onion industry commissioned Plant and Food Research to find out more about the disease, and this report has been sent to growers.

This year is the worst case of the leaf blight that anyone in the industry can remember, he said.

“No one can recall an attack by this particular fungus to this extent … so that does point potentially to, not a new pathogen, but more changing climate conditions.”

The industry would pour its resources and expertise into finding solutions, Mr Ahern said.

Potato growers also have poor season

Potato growers have also had a tough season – with water shortages, scorching temperatures, and several large storms.

No caption

Chris Claridge said there was increasing evidence that farmers were being directly impacted by climate change. Photo: Supplied

Potatoes New Zealand chief executive Chris Claridge said it was a clear link to climate change.

“What we’re seeing is a direct impact on farmers’ ability to plant and harvest potatoes, which is directly impacted on their profitability, and on our ability to generate export receipts.”

January was the hottest month on record, and that combined with several large cyclones had directly hit farmers in the pocket.

“We’re seeing increasing evidence that farmers are being directly impacted by climate change, and we now have to start the conversation about climate change and how we manage it going forward,” Mr Claridge said.

The key issue was how to make growers and farmers more resilient, he said.

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AGWEEK

Silver scurf, caused by a fungus, is a common potato disease and found in all major production areas of the U.S., including the Red River Valley of western Minnesota and northeast North Dakota.(Photo by Andrew Robinson)

Silver scurf: Great name, but bad for spuds

GRAND FORKS, N.D. — Fans of colorful, alliterative language may like “silver scurf.” Not Red River Valley potato growers; they see the crop disease as a growing threat.

“I’m getting more questions about it at harvest,” said Andy Robinson, Fargo, N.D.-based potato extension agronomist for both North Dakota State University and the University of Minnesota.

 He helped to organize potato educational sessions during the recent International Crop Expo in Grand Forks, N.D., and brought in Amanda Gevens to speak on the crop disease on Feb. 22.Gevens, a professor in the plant pathology department at the University of Wisconsin, also is seeing more cases of silver scurf. She described the disease “as gray, silver and shiny patches” that are “more obvious on red and purples,” but seen on yellow and russet potatoes, too.

Silver scurf, caused by a fungus, is a common potato disease and found in all major production areas of the United States, including the Red River Valley of western Minnesota and northeast North Dakota.

 The disease, specific to potato tubers, causes blemishes on spuds. Though the effect is mostly cosmetic, some potatoes affected by the disease have been rejected by industry buyers. Efforts to combat silver scurf are complicated by its close resemblance to black dot, another crop disease. Even Gevens can have trouble distinguishing the two diseases on affected potatoes.

 

“Whodunnit? Is it a silver scurf problem? Or is it a black dot problem,” she said. “It’s hard to tell these apart. Sometimes you can’t tell them apart.”

One important difference: silver scurf is tied to infected seed, while black dot is more of a soil/field debris issue, Gevens said.

 No commercial cultivars resistant to silver scurf are available yet, though work to develop them is underway.

Use of uninfected seed, which can be hard to get, helps to control the disease, as does early harvest and chemical use,

Storage conditions also influence the extent of silver scurf in affected potatoes. “High humidity in storage encourages it,” Gevens said.

Research also shows that smaller storage volumes help to control core temperatures and hold down silver scurf. But limiting storage volumes may not always be feasible, she said.

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CropLife

If you’re an ag retailer and you’re reading this report, I’d guess it’s fair to assume you’ve at least considered adding biopesticide products to your crop protection lineup.

My assumption is part idealism, part result of our 2017 CropLife® Biological Product Market Survey, which was sent to 29,000 ag retailers and other industry members nationwide. In the survey 67% of respondents said they plan to “increase the percentage of biological products” they sell/distribute in the future. Additionally, nearly half (49%) affirmed that their customers apply biologicals as “both seed treatments and topicals.”

Advanced Biological Marketing (ABM) is one such company finding success with seed-applied biological products. Dan Custis, CEO of the Van Wert, OH-based company, has been involved in the biologicals segment of the industry for almost 18 years now. He says that when the company first started marketing biologicals back in 2000 there was “very little adoption at all. Very little.”

“A lot of the types of products that we manufacture were referred to as kind of a bathtub mixture, or ‘Foo-foo Dust’,” Custis fondly recalls. “As we really got into it, we as a company put a lot of science and knowledge behind it.”

Ah yes, another aspect of biological products addressed in the survey. By far the top consensus among those surveyed was that biological products engender a “lack of trust around product performance” while a sizeable 72% of retailers responded that biopesticide products need “more research that demonstrates product effectiveness.”

At ABM, Custis says the company has research that shows about a seven bushel-per-acre yield increase over a five-year average on corn, and in soybeans that number is around two-and-a-half bushels per acre. Its top biopesticide, the seed-applied SabrEx (two strains of Trichoderma) is typically either applied downstream at the retailer, or on-farm by the grower. The company does work with some seed manufacturers as well, such as local Ohio seed company Rupp.

“We know that maybe we get six weeks of benefit at most from a chemical seed treatment depending on weather, unless it’s a systemic,” Custis says. “What biologicals bring to the table is the extension of that plant health beyond the six weeks. Biologicals are a living organism, they should be able to live on the root system of that plant up through flowering.”

ABM’s SabrEx is distributed via the traditional crop input retail channels, through well-known players such as Crop Production Services, WinField Uni­ted, Wil­bur-Ellis, and KOVA of Ohio. Production and formulation take place in Van Wert, while research & development is housed in the Finger Lakes region of Western New York in Geneva.

“Right now in R&D we’re taking a look at nematode control in soybeans and corn, that’s one of the products that we have committed to EPA for approval right now,” Custis shares. “That (product) would be a first, and we’ve certainly got other things in the pipeline that I’m not able to talk about at the moment.”

Where do others see the biopesticide industry headed in the next couple years? Again, we consult our survey responses, and with nearly three-fourths (72%) saying their customers prefer to apply biologicals not as one-off standalones, but actually in conjunction with conventional products. Well-known Iowa State University seed treatment expert Allison Robertson agrees.

“There has been quite a lot of work looking at biologicals, not as stand-alone treatments, but in partnership with treatments that address pathogens in the field,” she shared back in August. “In addition, nematicides have been developed recently to help fight off soybean nematodes.”

Which provides a perfect segue to discuss post-patent giant Albaugh and its intriguing BIOst system, which Director of Global Proprietary Products Chad Shelton describes as “the first complete biological seed treatment platform.”

“What’s really exciting for retailers,” he continues. “Is our BIOst 100 nematicide, which can be combined with synthetic chemistries to give both insect and nematode protection. This is the first biological nematicide registered for control of both soil dwelling pests, along with activity on nematodes. And when we combine that with a neonic seed treatment it’s giving the grower a better return-on-investment (ROI).”

That’s a trend Shelton is seeing play out more and more in the row crop biologicals space in the last couple years, shifting the deployment of biopesticides from one-off products to more integrated usage with conventional hard chemistries.

“It’s no longer about having one mode of action, or a specific agronomic response in the marketplace. To me that’s the biggest change,” he shares. “When you have biopesticides in combination with synthetics at a reduced rate you’re going to get enhanced performance plus ROI.”

Another area that Albaugh is focusing attention is developing products with what Shelton describes as “customization based on microclimate.”

“Our goal today is to customize seed treatment technologies based on micro climate and (regional) needs,” he adds.

 

 

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