Archive for the ‘Fungi’ Category

Infection with a fungus decreases the heat and cold tolerance of insects, influences insect behavior, study finds

by Pennsylvania State University

Sick insects stick to comfortable conditions
The researchers raised aphids (Acyrtociphon pisum) and ladybeetles (Hippodamia convergens) on faba bean (Vicia faba L.) plants. Credit: Penn State

We humans tend to avoid harsh conditions when we are sick, instead seeking out the comfort of our climate-controlled homes. New research shows that sick insects may also be sensitive to extreme temperatures, and it could be the pathogen itself that drives their behavior.

An international team of researchers has found that infection with a fungus reduces the thermal tolerance of an aphid and its beetle predator—the common ladybeetle—by more than 40 degrees Fahrenheit compared to healthy individuals. As a result, infected insects are less likely to cross into zones that are too warm or too cold, and this behavior change could have implications for predator-prey interactions as the climate changes. The findings published today in the journal Scientific Reports.

“The effects of climate change on insects are poorly understood,” said Edward Rajotte, professor of entomology, Penn State. “Our research showing that pathogens influence the tolerance of insects to extreme temperatures suggests that we cannot expect to understand how an organism will respond to environmental changes by studying the insect species alone; we need to also consider their pathogens.”

To conduct their study, the researchers raised aphids (Acyrtociphon pisum) and ladybeetles (Hippodamia convergens) on faba bean (Vicia faba L.) plants. Next, they sprayed spores of a fungus (Beauveria strain) in low and high quantities onto half of the aphids and beetles. The other half were maintained as controls. Two days after inoculation, the scientists collected adult aphids, both those infected with the fungus and those not infected with the fungus, from the experimental plots and measured physiological parameters, including critical temperature maximum and minimum, voluntary exposure to extreme temperatures and energetic costs under each condition. The team then released 300 adult beetles into the cages with the aphids, allowed the beetles to feed on the aphids for 2-3 days, during which they also became infected with the fungus, and then collected the beetles for physiological measurement.

Sick insects stick to comfortable conditions
The researchers examined how fungal infection influenced the behavior of aphids and beetles by transferring insects from the faba bean plants to a test arena, which provided space for the insects to freely move across extreme temperature conditions to access food in containers located at each end of the device. Credit: Penn State

To measure the heat tolerance limits of the insects, the team transferred individuals to a hotplate, increased the temperature at a rate of 32 degrees Fahrenheit per minute, and recorded the point at which they turned upside down and could no longer return to an upright position within five seconds. The team conducted the same procedure to examine the insects’ cold tolerance, except that they placed the insects into an insulated incubator, instead of onto a hotplate, and then reduced the temperature at a rate of 32 degrees Fahrenheit per minute. To examine whether fungal infection and temperature altered longevity in aphids and beetles, the researchers counted the number of days the insects survived after exposure to extreme temperatures.

“We found that the heat tolerance of fungus-infected aphids and beetles was reduced by 44 degrees Fahrenheit and 40 degrees Fahrenheit, respectively, while cold tolerance, was only reduced in the beetles,” said Mitzy Porras, postdoctoral scholar in entomology, Penn State. “In addition, survival was significantly reduced for infected aphids and beetles when they were exposed to both warm and cold extreme temperatures.”

Next, the researchers examined how fungal infection influenced the behavior of aphids and beetles by transferring insects from the faba bean plants to a test arena, which provided space for the insects to freely move across extreme temperature conditions to access food in containers located at each end of the device. They replicated the experiment 10 times for each species and treatment condition [aphid: healthy, infected (low and high fungal spore load); predator beetle: healthy, infected (low and high fungal spore load)].

“We recorded whether the insects explored, crossed into or relaxed within either of the extreme temperature zones,” said Carlos Navas, professor, University of Sao Paulo, who collaborated with Volker Loeschcke, professor at Aarhus University, in the design of the experimental arena.

Sick insects stick to comfortable conditions
This infrared image shows the differences in temperature across the chambers of the test arena. Credit: Penn State

The team found that almost 50% of aphids infected with a low fungal load opted not to cross extreme temperature zones, whereas 70% of aphids infected with a high fungal load did not cross extreme temperature zones. The percentages were similar for beetles.

“These findings suggest that the fungus might manipulate the insect host’s physiology and behavior in ways that favor fungal virulence since the fungus’s thermal thresholds are narrower than those of either of the insect hosts,” said Rajotte. “This is the first time, to our knowledge, that infection has been observed to shift the behavioral response of both a predator and prey in ways that reduce exposure to heat,” said Porras.

Porras noted that the response to thermal stress can vary among species, with some pathogens may influencing behaviors—such as crossing into extreme temperature zones—of certain insect species.

“This, in turn, may alter predator-prey interactions, food web structures and species distributions,” she said. “Our findings open the door to a wide array of potential research avenues related to the management of insect species and ecosystems.”

Jesper Sørensen, professor at Aarhus University, added, “We have learned that the relationships between pathogens and hosts are far more complex than we once thought. This study focuses on a specific case but has broad implications for the way we see these interactions, which can now be seen as another important dimension of ecology.”

Explore furtherDisease-causing virus manipulates crop plants to favor its vector

Journal information:Scientific Reports Provided by Pennsylvania State University

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Beech leaf disease is ravaging North American trees

Two new studies gauge impact and cause of forest blight

A view underneath North American beech trees
The fast-spreading beech leaf disease is starting to kill the widespread, majestic American beech, which can rise to about 40 meters tall and live about 400 years.MIRCEA COSTINA/ALAMY STOCK PHOTO


A tree disease first spotted 9 years ago in Ohio is now a leading threat to one of eastern North America’s most important trees. The poorly understood malady, called beech leaf disease, is spreading rapidly and killing both mature American beeches and saplings, new research shows.

“This study documents how rapidly [the disease] has spread since its first observation in 2012,” says Robert Marra, a forest pathologist at the Connecticut Agricultural Experiment Station who was not involved with the work.

American beeches (Fagus grandifolia) are found across the eastern United States and Canada. The trees, which can grow nearly 40 meters tall and live up to 400 years, are a major player in many forests. Beeches constitute more than 25% of forests in Vermont, for example.

Historically, a blight called beech bark disease has been the primary threat to the species. But now, beech leaf disease appears to pose a bigger danger. First spotted in northeastern Ohio, it causes parts of leaves to turn leathery and branches to wither. The blight can kill a mature tree within 6 to 10 years. It has now been documented in eight U.S. states and in Canada.

In Rhode Island, observers first spotted beech leaf disease in 2020, confined to a small area, says Heather Faubert of the University of Rhode Island’s Plant Protection Clinic who was not involved with the study. But, “This year, it’s everywhere.”

Beech leaf disease symptoms of dark banding between the leaf veins seen on beech tree leaves
Beech leaf disease causes some leaves to emerge with leathery, dark green parts. As the season continues, those parts may turn yellow or brown.MARY PITTS/ HOLDEN FORESTS AND GARDENS

To track the disease, Constance Hausman, an ecologist for a network of parks called the Cleveland Metroparks, and colleagues surveyed 64 0.04-hectare forest plots within 224 kilometers of Lake Erie in Ohio, Pennsylvania, New York, and Canada’s Ontario province. An analysis of 894 beeches in the plots found nearly half had the leaf disease, whereas just 34 had bark disease. Earlier surveys elsewhere had found the disease mostly attacked saplings, but the new work finds it is attacking mature trees, too, the team reported last month in Forest Ecology and Management. In forests near Lake Erie, beech leaf disease has now “become pervasive,” the group says.

The disease is “attacking the life cycle of beech trees in both directions,” Hausman says. The number of trees could fall so much in some forests that the species no longer serves key ecological functions, she warns, such as providing food and shelter for birds and other animals.

Another recent study by a different team examines an ongoing mystery: What exactly causes the disease? Earlier work raised suspicions that a tiny, previously unknown nematode worm that feeds on beech buds and leaves, dubbed Litylenchus crenatae mccannii, plays a role in spreading the blight.

Now, researchers report in Phytobiomes that when they examined diseased beech leaves, the tissues contained a fungus and four bacterial species also carried by the nematode. That suggests both the nematode and a pathogen it carries are contributing to the disease, says study co-author Pierluigi “Enrico” Bonello, an ecologist at Ohio State University, Columbus.

Marra is skeptical, however. He says one of the study’s suspects, Wolbachia, is known only to help its hosts. So he thinks its role in beech leaf disease, if any, might just be to strengthen the nematode’s attack.

So far, researchers haven’t identified a practical, cost-effective treatment for the disease, although some beeches appear to be resistant. But using those trees to breed new resistant strains could take decades, researchers say.

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Unravelling fungal spore release mechanics

by John Innes Centre

Unravelling fungal spore release mechanics
Credit: John Innes Centre

Researchers have shed light on a long-standing mystery concerning how fungal spores are released and dispersed.

Knowing how far these spores can travel could now help protect cereal crops from one of farming’s oldest adversaries, stem rust.

Working on the deadly stem rust pathogen, researchers from the John Innes Centre and the University of East Anglia (UEA) studied the dispersal of spores that are created from infection of the pathogen’s alternate host plant, the common hedgerow shrub barberry.

The study which appears in Communications Biology reveals the mechanism by which early-season spores are released from cluster cups of stem rust that form on barberry.

Stem rust spores are tightly packed in cluster cups and during dew or rainfall, water enters these structures, causing spores to expand. This process exerts substantial force on neighboring spores, whilst the water filling the gaps acts as a lubrication film.

This facilitates a catapult-style expulsion of spores from the cup structure, with single fungal spores reaching speeds of up to 0.754 meters per second. The study also confirmed that spores can be released in clusters, which acts to increase ejection speeds. Following discharge, most spores then likely dissociate to enhance subsequent wind transmission to neighboring crops.

By understanding this mechanism, it can now be used to aid farmers and legislators to assess the current local risk of disease spread from barberry bushes into neighboring cereal crops. Based on these findings the team has produced a new web resource, which simulates dispersal patterns and allows users to predict the likely distance spores could spread from an infected barberry bush.

Wheat stem rust is known as the “polio of agriculture” due to the severe threat it poses to wheat production around the globe.

The barberry shrub plays a critical role in the fungus’s life cycle; it acts as the site of sexual reproduction and its infection creates a reservoir of rust spores that can spread the disease back into neighboring cereal crops.

Despite the critical role of barberry as a source of wheat stem rust infection, the mechanics of how stem rust spores are released from barberry hedgerows and how far they can travel has puzzled scientists for more than a century.

Dr Vanessa Bueno-Sancho, the first author said: “Resolving these fundamental questions in spore release mechanics, finally allowed us to create a publicly available point-and-click web interface to assess the local risk of barberry plants spreading stem rust infection into cereal crops“.

Dr Diane Saunders, co-corresponding author, commented that “this research is particularly timely given that sporadic infections of wheat stem rust have been increasing in western Europe in the past decade and the popular hedgerow species barberry is also increasing in number. Knowing how far these spores can travel is crucial for guiding policy regarding safe distances for future barberry plantings from cereal crops, whilst also identifying current bushes at high risk as sources of future stem rust infection.”

Explore furtherFirst report in decades of a forgotten crop pathogen calls for critical close monitoring

More information: Vanessa Bueno-Sancho et al, Aeciospore ejection in the rust pathogen Puccinia graminis is driven by moisture ingress, Communications Biology (2021). DOI: 10.1038/s42003-021-02747-1

OCT 25, 2021

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View as a webpage ARS News Service
ARS News Service A field of corn
ARS and collaborating scientists have begun a multi-faceted fight against an emerging disease of corn called tar spot. ARS, Collaborating Scientists Tackling “Tar Spot” Threat to U.S. Corn For media inquiries contact: Jan Suszkiw, (202) 734-1176
October 25, 2021 Helping farmers turn the tide on an emerging disease of corn called tar spot is the focus of a multi-organization team of scientists, including from the Agricultural Research Service (ARS) in West Lafayette, Indiana. Caused by the fungus Phyllachora maydis, tar spot appears as black, roughly circular discolorations on the leaves, husks and stalks of corn plants. A tan halo sometimes surrounds the spore-filled spots, creating what’s known as a fish-eye lesion. Outbreaks of the disease, which was first detected in northern Indiana and Illinois in 2015, can reduce grain yields by 20 to 60 bushels an acre. Tar spot is now also found in corn-growing areas of Iowa, Michigan, Minnesota, Missouri, Ohio, Pennsylvania, Wisconsin, Florida, and southwestern Ontario, Canada. Although fungicides offer the hardest-hitting counterpunch, resistance to tar spot disease in corn is far more preferable, according to Steve Goodwin, a plant pathologist with the ARS Crop Production and Pest Control Research unit in West Lafayette, IN. There, in collaboration with fellow ARS scientists Raksha Singh, Matthew Helm and Charles Crane, Goodwin is working to manage tar spot on several research fronts: Screening existing commercial corn varieties and germplasm lines for their resistance or susceptibility to tar spot so that growers can adjust their disease management practices accordingly. Developing tools known as molecular markers to quickly and efficiently identify a gene known to confer tar spot resistance in corn, namely Qrtsc8. Identifying corn plants that lack the gene but are still resistant to the disease are also of interest, since an entirely new gene or genes unknown to science could be at play. Potentially, such sources of resistance could also prove useful in shoring up the crop’s defenses even further. Determining the biocontrol potential of a community of microorganisms known as the microbiome that was observed on tar-spot-resistant but not susceptible corn plants. “The main goal is to understand how environmental factors, plant growth stage and the associated corn microbiome affect tar spot disease progression and how all these factors are interconnected,” said Raksha.   Identification of several proteins the tar spot fungus uses to “short circuit” the defenses of susceptible plants—and how, in turn, these proteins could be exploited for better detection of different strains of the fungus and their severity in fields, noted Helm.     On other fronts, university collaborators are conducting research to optimize the timing of fungicide sprays and evaluating rotations of corn with non-host crops to reduce the disease’s severity and prevent the fungus from surviving the winter on debris from prior corn harvests. Researchers are also pouring through existing literature on the biology of the tar spot fungus and building on what’s known about it with genomic sequencing—a kind of decoding of its DNA playbook for causing disease in corn. One hope is that this will yield clues to new ways of controlling the fungus and preempting costly outbreaks like the one from 2018 to 2020, which claimed an estimated 241 million bushels of U.S. corn. The effort is being carried out under the auspices of the National Plant Disease Recovery System (NPDRS). Arising from a 2004 Homeland Security Presidential Directive, the NPDRS spotlights emerging plant disease threats and identifies what tools, infrastructure, communication networks and other resources will be necessary to protect U.S crops or recover from outbreaks that have already occurred. Besides ARS, other partner organizations are Purdue University, Michigan State University, Iowa State University, The Ohio State University, University of Missouri, University of Florida and the International Maize and Wheat Improvement Center in Mexico, where tar spot was first identified in 1904. The Agricultural Research Service is the U.S. Department of Agriculture’s chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in agricultural research results in $17 of economic impact. Interested in reading more about ARS research? Visit our news archive U.S. DEPARTMENT OF AGRICULTURE
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This deadly tree disease has been discovered in Europe for the first time


A pathway through a forest

A pathway through a forest   –   Copyright  CanvaBy Jonny Walfisz  •  Updated: 22/10/2021

A potentially deadly tree disease has been discovered in a forest in Cornwall, UK.

It is the first time the disease has been spotted within Europe and this has sparked concern among forest conservation groups. The disease can cause needle dropping, and lead to the death of branches and roots.

Although the pathogen can be found across multiple species, the potential introduction of a new tree disease once again shows the danger of monocultures – especially in reforestation efforts.

What’s the disease doing in Cornwall?

The disease’s full Latin name is Phytophthora pluvialis. The fungal infection affects a variety of trees including western hemlock, Douglas fir, tanoak and several pine species.

Until now, it has only ever been found on the west coast of America and in New Zealand.about:blank

But the first discovery of the disease in Europe came after a routine plant health check by the Forestry Commission, reports Cornwall Live.

Restrictions are being placed on an area between the towns of Bodmin and Liskeard in Cornwall to curb its spread.

“I urge all sectors to support efforts to tackle this pathogen by checking the health of western hemlock and Douglas fir trees,” said Nicola Spence, the UK chief plant health officer.

“Key symptoms to look for are lesions on the stem, branch or roots. Any sightings should be reported to the Forestry Commission via its Tree Alert online portal.”

The fight against monocultures

There is a growing movement fighting against the prevalence of monocultures in reforestation efforts.

Crop areas with just a single species lead to a heightened risk of diseases ravaging through entire areas.

International Day Against Monoculture Tree Plantations is on 21 September. The event demands people recognise that the replacement of a crop area with just one species of plant does not meaningfully benefit the environment.

A sole tree stands in a field Canva

“The large-scale plantation model cannot be decoupled from histories of colonialism, capitalism, patriarchy and racism,” says The World Rainforest Movement (WRM).

The WRM relates monoculture planting to historic crimes by western civilisation. “Crimes like the stealing of land and livelihoods, unlawful criminalization, sexual assault and harassment, human right violations, oppression of women, labour exploitation, environmental devastations and pollution.”

Reforest’Action, an activist movement for global reforestation, notes that movements such as the Bonn Challenge still allowed for monocultures in 45 per cent of the commitments.

“Creating a wooded field with nothing but eucalyptus planted cannot be called reforestation. For us, reforestation, in the only meaning that is worthwhile and serves all climate, biodiversity and socio-economic objectives, results in a diversity of tree species being planted or regenerated,” Stéphane Hallaire, President of Reforest’Action said.

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RAZOR 19:37, 18-Oct-2021Translate How these bees are reducing the need for harmful pesticidesCGTN


How can the world be fed without the use of pesticides? One company thinks it has the answer – and bees are going to help it achieve this. 

The company BeeVT, or Bee vectoring technology, has developed a natural fungicide to treat certain crops. And instead of spreading it with fossil fuel-run machines it has got bees on board, harnessing their natural pollination process to deliver targeted crop controls.09:4838

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Development of blight-resistant potato is a staggering breakthrough


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

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

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

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

Blight-resistant potato

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

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

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

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

Commercial scale

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

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

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

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

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

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

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

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

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Bacteria, fungi interact far more often than previously thought



Unique bioinformatics approaches help understand extent of fungal bacteriome

Los Alamos, N.M., Oct. 19, 2021 – In a novel, broad assessment of bacterial-fungal interactions, researchers using unique bioinformatics found that fungi host a remarkable diversity of bacteria, making bacterial-fungal interactions far more common and diverse than previously known.

“Until now, examples of bacterial-fungal interactions were pretty limited in number and diversity,” said Aaron Robinson, a biologist at Los Alamos National Laboratory and lead author of a new paper describing the research in Nature’s Communications Biology journal. “It had been assumed that bacterial-fungal associations might not be that common. But we found a lot of diverse bacteria that appear to associate with fungi, and we detected those associations at a frequent rate.”

The research contributes to an emerging understanding of the fungal bacteriome, the existence of bacteria both within and in close association with a fungal host, opening up possibilities for studying the interactions more intimately and connecting that research to issues such as ecosystem functioning and climate change impacts.

“This is a starting point to investigate mechanisms of bacterial-fungal interactions at a more intimate level,” said Robinson. “That research will be valuable for understanding what allows bacteria to associate with fungi, and how to best leverage that insight to accomplish goals for the Laboratory, for the Department of Energy, and for society in general. Understanding how these organisms interact with each other and contribute to larger systems is highly valuable in everything from modeling things like climate change to societally beneficial activities such as agricultural or industrial utilization of microbes.”

Researchers screened a total of 294 diverse fungal isolates from four culture collections from Europe, North America, and South America for potential bacterial associates. Collaborations with the Center for Integrated Nanotechnologies at Los Alamos allowed researchers to visually examine several of these associations using fluorescence in situ hybridization techniques.

These fluorescence microscopy examinations complemented the screening and confirmed the widespread and variable presence of bacterial associates among diverse fungal isolates and even within the hyphae (fungal tissue) of a single fungal host.

In addition to screening the culture collections, the research team also screened 408 fungal genome sequencing projects from the MycoCosm portal, a repository of fungal genome projects developed and maintained by the Department of Energy Joint Genome Institute.

Bacterial signatures were detected in 79 percent of the examined fungal genome projects. In multiple cases, the authors recovered complete or nearly complete genomes of these bacterial associates. Recovery of these fungal-associating bacterial genomes allowed for comparisons between fungal-associating and free-living bacteria.

Of the 702 total fungal isolates examined by the research team, bacterial associates were found in 88 percent—an unexpected detection rate relative to previous, more limited studies. The results shed light on the complexity and diversity of the fungal bacteriome across the fungal tree of life.

The study’s overview and description of diverse fungal-bacterial associations provides a path forward for understanding the associations in more depth. Continued analysis of the interactions will aid in a more complete understanding of environmental microbiome processes, particularly fungal and bacterial contributions to nutrient cycling, plant health and climate modeling.

Within the context of changing climate conditions, understanding how bacterial-fungal interactions impact plants, animals, and general ecosystem functioning in diverse environments and under diverse conditions, such as drought and warming, will also help predict and potentially manipulate the impacts of these interactions.

About Los Alamos National Laboratory
Los Alamos National Laboratory, a multidisciplinary research institution engaged in strategic science on behalf of national security, is managed by Triad, a public service oriented, national security science organization equally owned by its three founding members: Battelle Memorial Institute (Battelle), the Texas A&M University System (TAMUS), and the Regents of the University of California (UC) for the Department of Energy’s National Nuclear Security Administration.

Los Alamos enhances national security by ensuring the safety and reliability of the U.S. nuclear stockpile, developing technologies to reduce threats from weapons of mass destruction, and solving problems related to energy, environment, infrastructure, health, and global security concerns.


Communications Biology

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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Team engineers bioenergy-friendly fungi

by Karen Dunlap, Oak Ridge National Laboratory

Bioenergy – Friendly fungi
The ectomycorrhizal fungus Laccaria bicolor, shown in green, envelops the roots of a transgenic switchgrass plant. Switchgrass is not known to interact with this type of fungi naturally; the added PtLecRLK1 gene tells the plant to engage the fungus. Credit: ORNL, U.S. Dept. of Energy

An Oak Ridge National Laboratory team has successfully introduced a poplar gene into switchgrass, an important biofuel source, that allows switchgrass to interact with a beneficial fungus, ultimately boosting the grass’s growth and viability in changing environments.

Scientists observed the ectomycorrhizal fungus Laccaria bicolor as it enveloped the plant’s roots. This behavior, not known to occur naturally between these fungi and switchgrass, helps the plant to efficiently take up nutrients and water. This symbiotic relationship results in switchgrass that is more disease- and drought-resistant.

“We’ve engineered switchgrass to grow where it would typically struggle, that is, marginal land that is unsuitable for food crops,” said ORNL’s Jay Chen. “The fungus allows the switchgrass to absorb minerals from the soil.”

In a previous study, the team identified the receptor gene that looks out for friendly fungi. Next the team will validate the laboratory findings with a field study.

Explore furtherResearch enhances understanding of switchgrass, an important bioenergy crop

More information: Zhenzhen Qiao et al, Towards engineering ectomycorrhization into switchgrass bioenergy crops via a lectin receptor‐like kinase, Plant Biotechnology Journal (2021). DOI: 10.1111/pbi.13671Journal information:Plant Biotechnology JournalProvided by Oak Ridge National Laboratory

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Himachal cabbage crop hit by fungal disease

A team of scientists with farmers after examining the cabbage crop that has been hit by a fungal disease in the Chhota Bhangal valley of Kangra district earlier this week. (HT Photo)
A team of scientists with farmers after examining the cabbage crop that has been hit by a fungal disease in the Chhota Bhangal valley of Kangra district earlier this week. (HT Photo)

Updated on Sep 18, 2021 11:27 AM ISTBy HT Correspondent

Cabbage crop in a dozen villages of the remote Chhota-Bhangal valley in Kangra district has been hit by a fungus causing blackleg disease.

Scientists visited Dyot, Kothikohar, Nalhota, Badagran and Lohardi villages, the main cabbage-producing areas, earlier this week to examine the vegetable crops, particularly cabbage.

Also read: Rawat & team in Chandigarh today for meet as Punjab Congress continues to boil

“The cabbage crop has been hit by blackleg disease, caused by a fungus called Phoma lingam. It attacks many brassica crops and spreads rapidly. Plants can be affected at the seedling stage or at any stage in the field. Common symptoms are slight lesions on stems at cotyledon scars which elongate, turn brown with a black to purplish border, and become sunken, causing the stem to girdle and blacken,” said Arun Sood, the principal extension specialist, extension directorate of Chaudhary Sarwan Kumar Himachal Pradesh Agriculture University (HPAU), Palampur.RELATED STORIES

Farmers told about sprays to treat crop

Infected plants wilt, lodge, and die. On root crops, symptoms occur in the form of cankers on the fleshy roots and a dry rot may appear in storage.

Sood said black rot has been found infecting the cabbage crop. “Farmers have been told to treat the crop by spraying a solution of 3gm copper oxychloride per litre of water or 1% Bordeaux mixture,” he said.

Farmers have been advised to treat the seed with Bavistin fungicide while sowing.

The infected plants must be uprooted and destroyed and drainage of water in fields should be ensured, the scientist said.

A total of 152 hectares is under cabbage cultivation in the valley.

Monoculture increases disease risk

Kangra deputy director, agriculture, Jeet Singh Thakur said farmers have been urged to adopt the crop cycle to avoid infection. Continuous cropping increases the possibility of disease spread. The farmers in Chhota-Bhangal grow only one crop in a year. This is also an off season crop there.

Phoma lingam can survive for up to four years in the seed and three years in infected crop debris. “So, crop rotation is the best way for disease management. Radish, potato, coriander and French beans could be options. They can rotate these crops for the next two-three years so that the pathogen dies in the soil,” he said, adding that farmers of Chhota Bhangal have abandoned potato farming otherwise it was grown there in abundance.

The scientists found that the kidney beans crop was also affected by angular leaf spot disease, which can be treated by spraying 1gm Bastivin/litre of water solution.

Besides Sood, the team of experts comprised district agriculture officer Sushil Kumar and specialist Renu Sharma.

Chhota Bhangal valley is a remote village in Baijnath sub division of Kangra district.

The main source of income of locals is cultivation of cash crops such as cabbage, cauliflower, and kidney beans.SHARE THIS ARTICLE ON

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Fungal transplants from close relatives help endangered plants fight off disease

by American Phytopathological Society

Fungal transplants from close relatives help endangered plants fight off disease
Myrtle rust on the leaves of Eugenia koolauensis, a critically endangered endemic Hawaiian tree. Credit: M. K. Chock

For the endangered Hawaiian plant Eugenia koolauensis, fungi could be both its demise and its savior. The fungal pathogen myrtle rust (Austropuccinia psidii) has been devastating populations of the endemic tree, along with many other native and cultivated plants. However, researcher Mason Kamalani Chock thinks part of the solution might be more fungi.

Endophytic fungi, which reside inside leaves, often protect plants from pathogens. In a paper recently published in Phytobiomes Journal, Chock, along with fellow University of Hawaii researchers Benjamin Hoyt and Anthony Amend, treated E. koolauensis plants with endophytic fungi isolated from the leaves of closely related plant species, then assessed the resistance of these inoculated plants against myrtle rust. Although some individual strains of fungi seemed to decrease the pathogen severity, plants were most protected against the pathogen when treated with a complex mixture of microbes prepared from homogenized leaves of these related plants.

This finding suggests that microbiome-based treatments could be a promising avenue of myrtle rust management for these endangered plants and emphasizes the beneficial effects microbiomes can have on their host plants. “We need to be thinking about the entire microbial community rather than any individual player,” noted lead author Chock.

Fungal transplants from close relatives help endangered plants fight off disease
Scanning electron microscope image of myrtle rust. Credit: Mason K. Chock

While beneficial microbes have been applied as biological control agents in agriculture, this new research suggests they could also be an important tool for plant conservation. Diseases pose one of the biggest challenges for endangered plants, especially since low genetic variation in their small populations limits efforts to breed them for disease resistance. Other solutions are temporary or potentially harmful in other ways, such as pesticide applications, which have to be continually applied to be effective and can have deleterious effects on soil health.

Thus, mining plant microbiomes for beneficial strains or communities that can confer disease resistance may be a promising strategy for combating disease-driven declines of endangered plants. And even if these microbial treatments are not strong enough to make their hosts completely disease resistant, every little bit of protection can help these endangered plants. While Chock does not think the study’s findings indicate that microbiome transplants are “a silver bullet to stopping myrtle rust’s worldwide spread,” he thinks they may provide an “extra push for those plant species that are holding on to dear life due to the introduction of deleterious pathogens.”

Explore furtherResearchers sequence myrtle rust genome

More information: M. K. Chock et al, Mycobiome Transplant Increases Resistance to Austropuccinia psidii in an Endangered Hawaiian Plant, Phytobiomes Journal (2021). DOI: 10.1094/PBIOMES-09-20-0065-RProvided by American Phytopathological Society

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