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Genome studies uncover a new branch in fungal evolution

New research helps to resolve evolutionary origins of the ‘platypus of fungi’

Date:November 23, 2022Source:University of AlbertaSummary:About 600 seemingly disparate fungi that had resisted categorization have been shown to have a common ancestor, according to a a research team that used genome sequencing to give these peculiar creatures a new classification home.Share:

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About 600 seemingly disparate fungi that never quite found a fit along the fungal family tree have been shown to have a common ancestor, according to a University of Alberta-led research team that used genome sequencing to give these peculiar creatures their own classification home.

“They don’t have any particular feature that you can see with the naked eye where you can say they belong to the same group. But when you go to the genome, suddenly this emerges,” says Toby Spribille, principal investigator on the project and associate professor in the Department of Biological Sciences.

“I like to think of these as the platypus and echidna of the fungal world.”

Spribille, Canada Research Chair in Symbiosis, is referring to Australia’s famed Linnaean classification system-defying monotremes — which produce milk and have nipples, but lay eggs — that were the source of debate as to whether they were even real.

“Though nobody thought our fungi were fake, it’s similar because they all look totally different.”

Using DNA-based dating techniques, the team found that this new class of fungi, called Lichinomycetes, descended from a single origin 300 million years ago, or 240 million years before the extinction of dinosaurs.

David Díaz-Escandón, who performed the research as part of his PhD thesis, explains that these “oddball” fungi were previously sprinkled across seven different classes — a high-level grouping that in animals would be equivalent to the groups called mammals or reptiles.

Working with a team of researchers from seven countries to get material from the fungi, he sequenced 30 genomes and found that all classes but one descended from a single origin.

“They were classified, but they were classified into such different parts of the fungal side of the tree of life that people never suspected they were related to each other,” says Díaz-Escandón.

These fungi include forms as varied as earth tongues — eerie tongue-shaped fungi that shoot up vertically out of the ground — beetle gut microbes, and a fungus found in tree sap in northern Alberta. They also include some unusual lichens that survive in extreme habitats such as South America’s Atacama Desert, the driest non-polar desert in the world.

“What is really fascinating is that despite these fungi looking so different, they have a lot in common at the level of their genomes,” says Spribille. “Nobody saw this coming.”

Based on their genomes, which are small compared with those of other fungi, the team predicts that this group of fungi depend on other organisms for life.

“Their small genomes mean this class of fungi have lost much of their ability to integrate some complex carbohydrates,” said Spribille. “When we go back to look at each of these fungi, suddenly we see all of them are in a kind of symbiosis.”

He notes the new research will be important to the broader study of fungal evolution, specifically how fungi inherit important biotechnological features such as enzymes that break down plant matter.

The new group also could be a source of new information about past fungal extinctions.

“We think it’s likely that the diversity we see today is just the tip of the iceberg that survived. And we don’t have that many examples of this kind of thing in fungi.”

The research appears online in the journal Current Biology.

Story Source:

Materials provided by University of Alberta. Original written by Michael Brown. Note: Content may be edited for style and length.


Journal Reference:

  1. David Díaz-Escandón, Gulnara Tagirdzhanova, Dan Vanderpool, Carmen C.G. Allen, André Aptroot, Oluna Češka, David L. Hawksworth, Alejandro Huereca, Kerry Knudsen, Jana Kocourková, Robert Lücking, Philipp Resl, Toby Spribille. Genome-level analyses resolve an ancient lineage of symbiotic ascomycetesCurrent Biology, 2022; DOI: 10.1016/j.cub.2022.11.014

Cite This Page:

University of Alberta. “Genome studies uncover a new branch in fungal evolution: New research helps to resolve evolutionary origins of the ‘platypus of fungi’.” ScienceDaily. ScienceDaily, 23 November 2022. <www.sciencedaily.com/releases/2022/11/221123125118.htm>.

Secretion secrets revealed: Pathogen effector characterization for a devastating plant disease

Date:November 22, 2022Source:American Phytopathological Society

Summary:A recent study has discovered and characterized secreted proteins from the pathogen Candidatus Liberibacter solanacearum. These proteins, called effectors, offer clues into the manipulation tactics this bacterium uses to subdue its plant host. The study found that these effectors can be present in both the plant and insect host.Share:

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Sometimes the most niche plant pathogens pack the greatest punch. Such is the case for the Florida citrus industry, which has seen a 70% decline in its orange production since the introduction of Huanglongbing (citrus greening) in 2005. This disease is caused by the bacteria Candidatus Liberibacter asiaticus, which spreads via a flying insect — unlike most bacterial plant pathogens. When the insect feeds on the sugary sap of a plant, it deposits the bacteria into the veins of the plant, directly into the phloem, which allows the bacteria to follow this transport highway throughout the plant.

A close relative of the citrus greening pathogen, Candidatus Liberibacter solanacearum (CLso), is a newly emerging pathogen of tomato and potato. As this bacterium cannot survive outside of its hosts, very little is known about it, including how it causes disease. A recent study led by Paola Reyes Caldas, of the University of California, Davis, has discovered and characterized secreted proteins from the pathogen CLso. These proteins, called effectors, offer clues into the manipulation tactics this bacterium uses to subdue its plant host.

Newly published in Molecular Plant-Microbe Interactions, the study found that these effectors can be present in both the plant and insect host. Once inside the plant, these effectors can target various parts of the cell such as the iconic chloroplast, which are critical for the plant to perform photosynthesis. Additionally, these effectors are mobile in that they can travel from one plant cell to another. Corresponding author Gitta Coaker comments, “These effectors can also move from cell to cell, which could explain how Liberibacter can manipulate the plant while remaining restricted to the phloem. Unlike effectors from culturable leaf colonizing bacteria, the majority of Liberibacter effectors do not suppress plant immune responses, indicating that they possess unique activities.”

Whether these unique activities alter the phloem environment or insect attractiveness to facilitate pathogen spread remains to be seen, but this research offers an exciting starting point to unravelling this complex disease. Once targets of these effectors are identified, genetically engineering these important crops to prevent manipulation could be a fruitful solution to managing these diseases.


Story Source:

Materials provided by American Phytopathological SocietyNote: Content may be edited for style and length.


Journal Reference:

  1. Paola A. Reyes Caldas, Jie Zhu, Andrew Breakspear, Shree P. Thapa, Tania Y. Toruño, Laura M. Perilla-Henao, Clare Casteel, Christine R. Faulkner, Gitta Coaker. Effectors from a Bacterial Vector-Borne Pathogen Exhibit Diverse Subcellular Localization, Expression Profiles, and Manipulation of Plant DefenseMolecular Plant-Microbe Interactions®, 2022; DOI: 10.1094/MPMI-05-22-0114-R

Cite This Page:

American Phytopathological Society. “Secretion secrets revealed: Pathogen effector characterization for a devastating plant disease.” ScienceDaily. ScienceDaily, 22 November 2022. <www.sciencedaily.com/releases/2022/11/221122125304.htm>.

         Organizers              TAMAZ PATARKALASHVILI, Phd, Technical University, Georgia             Carlos José Bécquer Granados, PhD            Institute of Pastures and Forages Research (Cuba)              ABDEL AZIZ MOHAMED PhD Alexandria University, Egypt   Vanderlan da Silva Bolzani,PhD AUIN-UNESP Brazil, Brazil    Anjanapura V. Raghu, PhD Jain University India             Carlos Ruiz Garvia PhD                                     UNFCCC Global Innovation Hub,           Germany                      MANAGEMENT            Mr. Jim Anderson            Plant-2023 Organizing Committee            96 Mainard Crescent            ON L6R 2T8            Brampton Canada           plant@massivegroup.org           massivegroup33@gmail.com           plant@plantaconferences.com            Dear Colleague,     We are delighted to announce that the 3rd International Conference on Plant Science and Molecular Biology will be held in Portugal taking place on 17-19, May 2023 in Lisbon, Portugal.   PLANT-2023 Conference remains the only annual event of its kind gathering leading international researchers and experts in the field of Plant Science.   On behalf of the organizing committee, I am pleased to invite you to speak at the 3rd International Conference on Plant Science and Molecular Biology on 17-19, May 2023.   The meeting will consist of selected oral presentations, poster sessions, and keynote addresses.  Special Awards for 3 best Oral Communication and 3 best Poster for young presenters (< 35 years old).   Should you have any query or you need any further information about the Conference please address your correspondence to plant@massivegroup.org ; massivegroup33@gmail.com   We will be really pleased if you could join us and give an oral presentation of your recent research for scientific sessions and abstract submission, Please Click   Abstract Submission   Looking forward to hearing from you,     Sincerely, Jim Anderson Conference Manager    

Unraveling the Relationship Between the HLB Bacterium and Trees

 DECEMBER 2, 2022 HLB MANAGEMENT RESEARCH

At the heart of the HLB threatening the Florida citrus industry is a complex exchange between the citrus tree and an insidious bacterium.

bacterium
Photo courtesy of UF/IFAS photography

University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers continue to study the bacterium that causes HLB. They are learning more about how it works within the citrus tree in an effort to find viable solutions for growers.

In a new paper, Amit Levy, assistant professor of plant pathology, and first author Chiara Bernardini, a post-doctoral researcher, have discovered some new ways that the bacteria interact with a citrus tree’s natural defenses. Their findings shed light on the complexity of the disease path within the tree and what it means for scientists looking to mitigate its deadly impact.

Levy and Bernardini discovered how the bacteria and citrus tree engage in a “back-and-forth” reactionary relationship. Levy and others showed that once infected with the Candidatus Liberibacter asiaticus (CLas) bacterium, the tree’s defense system starts to generate callose in the phloem. Callose is a material that essentially “plugs” the phloem and generates something called reactive oxygen species (ROS).

In plants, ROS is involved in a plant’s defense systems and impacts a plant’s tolerance to various types of stress. Presence of a pathogen like CLas can increase ROS production to a negative effect and eventually cause cell death.

Levy’s research found that the CLas bacteria responded to the generation of callose and ROS by actually reducing them, allowing bacteria to once again replicate and transport throughout the tree.

This back-and-forth repetitive relationship of callose plugging and ROS accumulation ­— and then their elimination by Clas — is a complicated one and replicates an immune response competition between hosts and pathogens found in many other diseases.

Citrus varieties that maintain a fine balance between callose and ROS generation and then elimination without either side gaining “control” may be more inclined to continue to produce fruit over many years.

“This research demonstrates the complicated, intertwined relationship between the HLB bacteria and the tree’s immune defense system,” Levy said. “The fact that CLas developed mechanisms to suppress the immunity tells us that the plant immunity is critical to stop the bacteria. The HLB disease is about both the pathogen and the immune response, and their interaction. It is a fine balance.”

Learning more about how and when to stop this back-and-forth relationship and how it varies among different citrus varieties may bring scientists closer to finding sustainable solutions to fighting HLB.

Levy’s research appears in the July issue of Plant Physiology.

Source: UF/IFAS

Saturday, 26 November 2022 14:55:42

PestNet

Grahame Jackson posted a new submission ‘Trichoderma: a multipurpose, plant-beneficial microorganism for eco-sustainable agriculture’

Submission

Trichoderma: a multipurpose, plant-beneficial microorganism for eco-sustainable agriculture

Nature
https://www.nature.com/articles/s41579-022-00819-5

Nature Reviews Microbiology (2022)

Abstract

Trichoderma is a cosmopolitan and opportunistic ascomycete fungal genus including species that are of interest to agriculture as direct biological control agents of phytopathogens. Trichoderma utilizes direct antagonism and competition, particularly in the rhizosphere, where it modulates the composition of and interactions with other microorganisms. In its colonization of plants, on the roots or as an endophyte, Trichoderma has evolved the capacity to communicate with the plant and produce numerous multifaceted benefits to its host. The intricacy of this plant–microorganism association has stimulated a marked interest in research on Trichoderma, ranging from its capacity as a plant growth promoter to its ability to prime local and systemic defence responses against biotic and abiotic stresses and to activate transcriptional memory affecting plant responses to future stresses. This Review discusses the ecophysiology and diversity of Trichoderma and the complexity of its relationships in the agroecosystem, highlighting its potential as a direct and indirect biological control agent, biostimulant and biofertilizer, which are useful multipurpose properties for agricultural applications. We also highlight how the present legislative framework might accommodate the demonstrated evidence of Trichoderma proficiency as a plant-beneficial microorganism contributing towards eco-sustainable agriculture.


Panama disease in bananas could be controlled by fungicides, study says

November 09 , 2022

Panama disease in bananas could be controlled by fungicides, study says

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Scientists at the U.K.’s University of Exeter have found that a particular class of fungicides are able to suppress Panama disease in banana plants.

The disease is caused by the fungus Fusarium oxysporum cubense Race 1, and its spread decimated the world’s banana supply during the 1950. Because of its known resistance to other fungicides, the study sought to better understand why chemical control of Panama disease had previously failed. 

Funded by the BBSRC Global Food Systems initiative (GFS), the team led by Professor Gero Steinberg and Professor Sarah Gurr used a multi-disciplinary approach, combining expertise in cell and molecular biology, bioinformatics and plant pathology.

The research team discovered that a specialized class of fungicides, not previously used, can suppress Panama disease and maintain plant health in the presence of the pathogen. This discovery provides a significant step forwards in the fight to protect this valuable crop.

“Bananas are Britain’s favorite fruit and Panama disease may ‘wipe’ them off the supermarket shelves. On top, millions of people in producer countries live on bananas. Providing an important step towards safeguarding bananas from Panama disease gives me great pride,” said Professor Steinberg.

Professor Sarah Gurr, the plant pathology expert who led all work on banana infection and pathogen cultivation, said: “Our success is due to an enormous amount of dedicated work over several years with co-workers with hugely disparate skills. We are highly delighted and excited by the outcome of our work and by the glimmer of hope that the beloved banana may remain as part of our daily diet.”

The paper, published in the journal PLOS Pathogens, is entitled: “Multi-site fungicides suppress banana Panama disease, caused by Fusarium oxysporum f. sp. cubense Tropical Race 4.

Climate change means farmers in West Africa need more ways to combat pests

by Loko Yêyinou Laura Estelle, The Conversation

worm on corn
Credit: Unsplash/CC0 Public Domain

The link between climate change and the spread of crop pests has been established by research and evidence.

Farmers are noticing the link themselves, alongside higher temperatures and greater variability in rainfall. All these changes are having an impact on harvests across Africa.

Changing conditions sometimes allow insects and diseases to spread and thrive in new places. The threat is greatest when there are no natural predators to keep pests in check, and when human control strategies are limited to the use of unsuitable synthetic insecticides.

Invasive pests can take hold in a new environment and cause very costly damage before national authorities and researchers are able to devise and fund ways to protect crops, harvests and livelihoods.

Early research into biological control methods (use of other organisms to control pests) shows promise for safeguarding harvests and food security. Rapid climate change, however, means researchers are racing against time to develop the full range of tools needed for a growing threat.

The most notable of recent invasive pests to arrive in Africa was the fall armyworm, which spread to the continent from the Americas in 2016.

Since then, 78 countries have reported the caterpillar, which attacks a range of crops including staples like maize and has caused an estimated US$9.4 billion in losses a year.

African farmers are still struggling to contain the larger grain borer, or Prostephanus truncatus Horn, which reached the continent in the 1970s. It can destroy up to 40% of stored maize in just four months. In Benin, it is a particular threat to cassava chips, and can cause losses of up to 50% in three months.

It’s expected that the larger grain borer will continue to spread as climatic conditions become more favorable. African countries urgently need more support and research into different control strategies, including the use of natural enemies, varietal resistance and biopesticides.

My research work is at the interface between plants, insects and genetics. It’s intended to contribute to more productive agriculture that respects the environment and human health by controlling insect pests with innovative biological methods.

For example, we have demonstrated that a species of insect called Alloeocranum biannulipes Montr. and Sign. eats some crop pests. Certain kinds of fungi (Metarhizium anisopliae and Beauveria bassiana), too, can kill these pests. They are potential biological control agents of the larger grain borer and other pests.

Improved pest control is especially important for women farmers, who make up a significant share of the agricultural workforce.

In Benin, for example, around 70% of production is carried out by women, yet high rates of illiteracy mean many are unable to read the labels of synthetic pesticides.

This can result in misuse or overuse of chemical crop protection products, which poses a risk to the health of the farmers applying the product and a risk of environmental pollution.

Moreover, the unsuitable and intensive use of synthetic insecticides could lead to the development of insecticide resistance and a proliferation of resistant insects.

Biological alternatives to the rescue

Various studies have shown that the use of the following biological alternatives would not only benefit food security but would also help farmers who have limited formal education:

  1. Natural predators like other insects can be effective in controlling pests. For example I found that the predator Alloeocranum biannulipes Montr. and Sign. is an effective biological control agent against a beetle called Dinoderus porcellus Lesne in stored yam chips and the larger grain borer in stored cassava chips. Under farm storage conditions, the release of this predator in infested yam chips significantly reduced the numbers of pests and the weight loss. In Benin, yams are a staple food and important cash crop. The tubers are dried into chips to prevent them from rotting.
  2. Strains of fungi such as Metarhizium anisopliae and Beauveria bassiana also showed their effectiveness as biological control agents against some pests. For example, isolate Bb115 of B. bassiana significantly reduced D. porcellus populations and weight loss of yam chips. The fungus also had an effect on the survival of an insect species, Helicoverpa armigera (Hübner), known as the cotton bollworm. It did this by invading the tissues of crop plants that the insect larva eats. The larvae then ate less of those plants.
  3. The use of botanical extracts and powdered plant parts is another biological alternative to the use of harmful synthetic pesticides. For example, I found that botanical extracts of plants grown in Benin, Bridelia ferruginea, Blighia sapida and Khaya senegalensis, have insecticidal, repellent and antifeedant activities against D. porcellus and can also be used in powder form to protect yam chips.
  4. My research also found that essential oils of certain leaves can be used as a natural way to stop D. porcellus feeding on yam chips.
  5. I’ve done research on varietal (genetic) resistance too and found five varieties of yam (Gaboubaba, Boniwouré, Alahina, Yakanougo and Wonmangou) were resistant to the D. porcellus beetle.

Next generation tools

To develop efficient integrated pest management strategies, researchers need support and funding. They need to test these potential biocontrol methods and their combinations with other eco-friendly methods in farm conditions.

Investing in further research would help to bolster the African Union’s 2021–2030 Strategy for Managing Invasive Species, and protect farmers, countries and economies from more devastating losses as climate change brings new threats.

Initiatives like the One Planet Fellowship, coordinated by African Women in Agricultural Research and Development, have helped further the research and leadership of early-career scientists in this area, where climate and gender overlap.

But much more is needed to unlock the full expertise of women and men across the continent to equip farmers with next generation tools for next generation threats.

Provided by The Conversation 

This article is republished from The Conversation under a Creative Commons license. Read the original article.


Explore further

Why African farmers should balance pesticides with other control methods

University of Adelaide researchers developing gene drive technology to combat invasive mice

ABC Rural

 / By Dylan Smith and Brooke Neindorf

Posted Thu 10 Nov 2022 at 1:49amThursday 10 Nov 2022 at 1:49am, updated Thu 10 Nov 2022 at 3:32pmThursday 10 Nov 2022 at 3:32pm

five mice on top of each other
The technology aims to make future females of invasive mice species infertile.(Supplied: University of Adelaide)

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Researchers at the University of Adelaide have released their findings about the potential effectiveness of gene drive technology to control invasive mice.

Key points:

  • A South Australian research team identifies new technology it hopes will eventually curb mice numbers
  • Co-author Luke Gierus says the technology is the first feasible genetic biocontrol tool for invasive mammals
  • Researchers believe the technology can be developed to work against other invasive pests

The technology — named t-CRISPR — uses sophisticated computer modelling on laboratory mice.

DNA technology is used to make alterations to a female fertility gene and, once the population is saturated with the genetic modification, the females that are generated will be infertile.

Research paper co-first author and post-graduate student Luke Gierus said the technology was the first genetic biological control tool for invasive animals.

“So we can do an initial seeding of a couple hundred mice and that will be enough, in theory, to spread and eradicate an entire population,” he said.

“We’ve done some modelling in this paper and we’ve shown using this system we can release 256 mice into a population of 200,000 on an island and that would eradicate those 200,000 in about 25 years.”

person with facial hair in their mid 20's smiles at the camera
Paper co-author Luke Gierus says the technology has a long way to go but signs are promising.(Supplied: Luke Gierus)

The team has been undertaking the research for five years.

Mr Gierus said the next step would be to continue testing in laboratories before releasing mice onto islands where the team could safely monitor the effects.

He said the method was far more humane than other methods, such as baiting.

“It’s potentially a new tool that can either be used alongside the current technology or by itself,” Mr Gierus said.

“This is quite a revolutionary technology that gives us another way to try and control and suppress mice.”

Mice scramble over a white background
Invasive mouse species have caused millions of dollars in damages to crops in recent years.(ABC News Video)

Technology welcomed

CSIRO research officer and mouse expert Steve Henry said wiping out mice from agricultural systems would be a wonderful outcome but he could not see it happening any time soon.

“The farming community are fantastic in terms of their willingness to adopt new ideas, so while it’s really important to do this research, the time frame is long and we need to make sure we don’t say we have a solution that’s just around the corner.”

But Mr Henry believed the technology would be welcomed with open arms when it did arrive.

A man in a hat weights a mouse at the end of a string
CSIRO researcher Steve Henry says farmers are keen on innovative solutions.(ABC News: Alice Kenney)

“While we need to be focusing on the stuff that we can use to control mice now, we also need to be looking outside of the box in terms of these new technologies … into the future,” he said.

Mr Henry said that while he did not have extensive knowledge about the technology, it was exciting.

“The other thing that is really cool is you can make it so it doesn’t affect native rodent species as well,” he said.

Farmers group welcomes research

Grain Producers South Australia chief executive officer Brad Perry said introduced mouse species could severely damage crops and equipment, and recent plagues had been destructive.

“When it comes to pests and diseases in grain and agriculture more broadly, we need to be innovative and think outside the square on prevention measures,” Mr Perry said.

He said technology such as this could help farmers save money in the long run.

a mouse held by the back of its neck stares into the camera lense
Invasive mice species can have a devastating impact on crops.(Supplied: Michael Vincent)

“Grain producers currently manage populations by minimising the food source at harvest, and if populations require [it] zinc phosphide baits are used,” Mr Perry said.

“However, using baits adds to input costs, it is not always readily available and there are limited windows to when this is effective.”

Mr Perry said many farmers would be keen to see the technology in the near future.

“We are supportive of additional tools that help reduce introduced mouse populations — particularly when it involves local world-leading research at the University of Adelaide — which is targeted, reduces inputs and is sustainable.”

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Posted 10 Nov 202210 Nov 2022, updated 10 Nov 202210 Nov 2022

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Combatting soil-borne pathogens and nematodes vital for food security

   Delhi Bureau  0 Comments CIMMYT  9 min read

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08 November 2022, Mexico: The International Maize and Wheat Improvement Center (CIMMYT) coordinated the VIII International Cereal Nematode Symposium between September 26-29, in collaboration with the Turkish Ministry of Agriculture and Forestry, the General Directorate of Agricultural Research and Policies and Bolu Abant Izzet Baysal University.

As many as 828 million people struggle with hunger due to food shortages worldwide, while 345 million are facing acute food insecurity – a crisis underpinning discussions at this symposium in Turkey focused on controlling nematodes and soil-borne pathogens causing reduced wheat yields in semi-arid regions.

A major staple, healthy wheat crops are vital for food security because the grain provides about a fifth of calories and proteins in the human diet worldwide.

Seeking resources to feed a rapidly increasing world population is a key part of tackling global hunger, said Mustafa Alisarli, the rector of Turkey’s Bolu Abant Izzet Baysal University in his address to the 150 delegates attending the VIII International Cereal Nematode Symposium in the country’s province of Bolu.

Suat Kaymak, Head of the Plant Protection Department, on behalf of the director general of the General Directorate of Agricultural Research and Policies (GDAR), delivered an opening speech, emphasizing the urgent need to support the CIMMYT Soil-borne Pathogens (SBP) research. He stated that the SBP plays a crucial role in reducing the negative impact of nematodes and pathogens on wheat yield and ultimately improves food security. Therefore, the GDAR is supporting the SBP program by building a central soil-borne pathogens headquarters and a genebank in Ankara.

Discussions during the five-day conference were focused on strategies to improve resilience to the Cereal Cyst Nematodes (Heterodera spp.) and Root Lesion Nematodes (Pratylenchus spp.), which cause root-health degradation, and reduce moisture uptake needed for proper development of wheat.

Richard Smiley, a professor emeritus at Oregon State University, summarized his research on nematode diseases. He has studied nematodes and pathogenic fungi that invade wheat and barley roots in the Pacific Northwest of the United States for 40 years. “The grain yield gap – actual versus potential yield – in semiarid rainfed agriculture cannot be significantly reduced until water and nutrient uptake constraints caused by nematodes and Fusarium crown rot are overcome,” he said.

Experts also assessed patterns of global distribution, exchanging ideas on ways to boost international collaboration on research to curtail economic losses related to nematode and pathogen infestations.

A special session on soil-borne plant pathogenic fungi drew attention to the broad spectrum of diseases causing root rot, stem rot, crown rot and vascular wilts of wheat.

Soil-borne fungal and nematode parasites co-exist in the same ecological niche in cereal-crop field ecosystems, simultaneously attacking root systems and plant crowns thereby reducing the uptake of nutrients, especially under conditions of soil moisture stress.

Limited genetic and chemical control options exist to curtail the damage and spread of these soil-borne problems which is a challenge exacerbated by both synergistic and antagonistic interactions between nematodes and fungi.

Nematodes, by direct alteration of plant cells and consequent biochemical changes, can predispose wheat to invasion by soil borne pathogens. Some root rotting fungi can increase damage due to nematode parasites.

Integrated managementFor a holistic approach to addressing the challenge, the entire biotic community in the soil must be considered, said Hans Braun, former director of the Global Wheat Program at CIMMYT.

Braun presented efficient cereal breeding as a method for better soil-borne pathogen management. His insights highlighted the complexity of root-health problems across the region, throughout Central Asia, West Asia and North Africa (CWANA).

Richard A. Sikora, Professor emeritus and former Chairman of the Institute of Plant Protection at the University of Bonn, stated that the broad spectrum of nematode and pathogen species causing root-health problems in CWANA requires site-specific approaches for effective crop health management. Sikora added that no single technology will solve the complex root-health problems affecting wheat in the semi-arid regions. To solve all nematode and pathogen problems, all components of integrated management will be needed to improve wheat yields in the climate stressed semi-arid regions of CWANA.

Building on this theme, Timothy Paulitz, research plant pathologist at the United States Department of Agriculture Agricultural Research Service (USDA-ARS), presented on the relationship between soil biodiversity and wheat health and attempts to identify the bacterial and fungal drivers of wheat yield loss. Paulitz, who has researched soil-borne pathogens of wheat for more than 20 years stated that, “We need to understand how the complex soil biotic ecosystem impacts pathogens, nutrient uptake and efficiency and tolerance to abiotic stresses.”

Julie Nicol, former soil-borne pathologist at CIMMYT, who now coordinates the Germplasm Exchange (CAIGE) project between CIMMYT and the International Center for Agricultural Research in the Dry Areas (ICARDA) at the University of Sydney’s Plant Breeding Institute, pointed out the power of collaboration and interdisciplinary expertise in both breeding and plant pathology. The CAIGE project clearly demonstrates how valuable sources of multiple soil-borne pathogen resistance in high-yielding adapted wheat backgrounds have been identified by the CIMMYT Turkey program, she said. Validated by Australian pathologists, related information is stored in a database and is available for use by Australian and international breeding communities.

Economic losses

Root-rotting fungi and cereal nematodes are particularly problematic in rainfed systems where post-anthesis drought stress is common. Other disruptive diseases in the same family include dryland crown and the foot rot complex, which are caused mainly by the pathogens Fusarium culmorum and F. pseudograminearum.

The root lesion nematode Pratylenchus thornei can cause yield losses in wheat from 38 to 85 percent in Australia and from 12 to 37 percent in Mexico. In southern Australia, grain losses caused by Pratylenchus neglectus ranged from 16 to 23 percent and from 56 to 74 percent in some areas.

The cereal cyst nematodes (Heterodera spp.) with serious economic consequences for wheat include Heterodera avenae, H. filipjevi and H. latipons. Yield losses due to H. avenae range from 15 to 20 percent in Pakistan, 40 to 92 percent in Saudi Arabia, and 23 to 50 percent in Australia.

In Turkey, Heterodera filipjevi has caused up to 50 percent crop losses in the Central Anatolia Plateau and Heterodera avenae has caused up to 24 percent crop losses in the Eastern Mediterranean.

The genus Fusarium which includes more than a hundred species, is a globally recognized plant pathogenic fungal complex that causes significant damage to wheat on a global scale.

In wheat, Fusarium spp. cause crown-, foot-, and root- rot as well as head blight. Yield losses from Fusarium crown-rot have been as high as 35 percent in the Pacific Northwest of America and 25 to 58 percent in Australia, adding up losses annually of $13 million and $400 million respectively, due to reduced grain yield and quality. The true extent of damage in CWANA needs to be determined.

Abdelfattah Dababat, CIMMYT’s Turkey representative and leader of the soil-borne pathogens research team said, “There are examples internationally, where plant pathologists, plant breeders and agronomists have worked collaboratively and successfully developed control strategies to limit the impact of soil borne pathogens on wheat.” He mentioned the example of the development and widespread deployment of cereal cyst nematode resistant cereals in Australia that has led to innovative approaches and long-term control of this devastating pathogen.

Dababat, who coordinated the symposium for CIMMYT, explained that, “Through this symposium, scientists had the opportunity to present their research results and to develop collaborations to facilitate the development of on-farm strategies for control of these intractable soil borne pathogens in their countries.”

Paulitz stated further that soil-borne diseases have world-wide impacts even in higher input wheat systems of the United States. “The germplasm provided by CIMMYT and other international collaborators is critical for breeding programs in the Pacific Northwest, as these diseases cannot be managed by chemical or cultural techniques,” he added.

Road ahead

Delegates gained a greater understanding of the scale of distribution of cereal cyst nematodes and soil borne pathogens in wheat production systems throughout West Asia, North Africa, parts of Central Asia, Northern India, and China.

After more than 20 years of study, researchers have recognized the benefits of planting wheat varieties that are more resistant. This means placing major emphasis on host resistance through validation and integration of resistant sources using traditional and molecular methods by incorporating them into wheat germplasm for global wheat production systems, particularly those dependent on rainfed or supplementary irrigation systems.

Sikora stated that more has to be done to improve Integrated Pest Management (IPM), taking into consideration all tools wherever resistant is not available. Crop rotations for example have shown some promise in helping to mitigate the spread and impact of these diseases.

“In order to develop new disease-resistant products featuring resilience to changing environmental stress factors and higher nutritional values, modern biotechnology interventions have also been explored,” Alisarli said.

Brigitte Slaats and Matthias Gaberthueel, who represent Swiss agrichemicals and seeds group Syngenta, introduced TYMIRIUM® technology, a new solution for nematode and crown rot management in cereals. “Syngenta is committed to developing novel seed-applied solutions to effectively control early soil borne diseases and pests,” Slaats said.

It was widely recognized at the event that providing training for scientists from the Global North and South is critical. Turkey, Austria, China, Morocco, and India have all hosted workshops, which were effective in identifying the global status of the problem of cereal nematodes and forming networks and partnerships to continue working on these challenges.

Also Read: Agriculture and the agricultural economy is the strength of India: Union Agriculture Minister

(For Latest Agriculture News & Updates, follow Krishak Jagat on Google News)

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Now, an international team of experts is providing a convincing overview of the role of climate change and climatic extremes in driving insect decline.

11-07-2022

Insects need urgent help to survive climate change

ByKatherine Bucko

Earth.com staff writer

While the scientific community has previously warned about an alarming decline in insect populations, not much has been done to address this issue on a global scale. Now, an international team of experts is providing a convincing overview of the role of climate change and climatic extremes in driving insect decline. 

“If no action is taken to better understand and reduce the impact of climate change on insects, we will drastically limit our chances of a sustainable future with healthy ecosystems.” This is the warning from a paper composed by 70 scientists from 19 countries around the world as part of the of the Scientists’ Warning series. 

“Climate change aggravates other human-mediated environmental problems,” said lead author Jeffrey Harvey from the Netherlands Institute of Ecology. “Including habitat loss and fragmentation, various forms of pollution, overharvesting and invasive species.”

Insects play critical roles in many ecosystems, making this problem incredibly urgent, as ecosystem loss is on the rise.

“The gradual increase in global surface temperature impacts insects in their physiology, behaviour, phenology, distribution and species interactions. But also, more and longer lasting extreme events leave their traces,” said Harvey.

While fruit flies, butterflies and flour beetles have the capacity to survive heat waves, they can become sterilized and unable to reproduce. Bumblebees, in particular, are very sensitive to heat, and climate change is now considered the main factor in the decline of several North American species.

“Cold-blooded insects are among the groups of organisms most seriously affected by climate change, because their body temperature and metabolism are strongly linked with the temperature of the surrounding air,” said Harvey.

Insects also play a critical role in supporting the global economy through services such as pollination, pest control, nutrient cycling and decomposition of waste. These vitally important services help to sustain humanity and provide billions of dollars annually to the global economy. 

“The late renowned ant ecologist Edward O. Wilson, once argued that ‘it is the little things that run the world’. And they do!’” said Harvey.

The ability for insects to adapt to global warming is further impacted by human threats such as habitat destruction and pesticides. Heatwaves and droughts can drastically harm insect populations in the short term, making insects less able to adapt to more gradual warming.  

The paper includes solutions and management strategies. Individuals can help by caring for different wild plants, providing food and shelter for insects during climate extremes. Reducing the use of pesticides and other chemicals is also recommended. 

“Insects are tough little critters and we should be relieved that there is still room to correct our mistakes,” said Harvey. “We really need to enact policies to stabilise the global climate. In the meantime, at both government and individual levels, we can all pitch in and make urban and rural landscapes more insect-friendly.”

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By Katherine BuckoEarth.com Staff Writer

Potential use of entomopathogenic and mycoparasitic fungi against powdery mildew in aquaponics

Aquaponics has the potential to produce sustainable and accessible quality food through the integration of hydroponics and aquaculture. Plants take up dissolved nutrients in fish wastewater, allowing water reuse for fish. However, the simultaneous presence of fish and plants in the same water loop has made phytosanitary treatments of diseases such as powdery mildew problematic due to risks of toxicity for fish and beneficial bacteria, limiting its commercialization.

Entomopathogenic and mycoparasitic fungi have been identified as safe biological control agents for a broad range of pests. This study aimed to investigate the efficacy of entomopathogenic fungi, Lecanicillium attenuatum (LLA), Isaria fumosorosea (IFR), and mycoparasitic fungus Trichoderma virens (TVI) against Podosphaera xanthii. Also, we investigated the possible harmful effects of the three fungal biocontrol agents in aquaponics by inoculating them in aquaponics water and monitoring their survival and growth. The findings showed that the three biocontrol agents significantly suppressed the powdery mildew at 107 CFU/ml concentration.

Under greenhouse conditions (65-73% relative humidity (RH)), a significant disease reduction percentage of 85% was recorded in L. attenuatum-pretreated leaves. IFR-treated leaves had the least AUDPC (area under disease progress curve) of ~434.2 and disease severity of 32% under 65-73% RH. In addition, L. attenuatum spores were the most persistent on the leaves; the spores population increased to 9.54 × 103 CFUmm-2 from the initial 7.3 CFUmm-2 under 65-73%. In contrast, in hydroponics water, the LLA, IFR, and TVI spores significantly reduced by more than 99% after 96 hrs. Initial spore concentrations of LLA of 107 CFU/ml spores were reduced to 4 x 103 CFU after 96 hrs. Though the results from this study were intended for aquaponics systems, the relevance of the results to other cultivation systems are discussed.

Read the complete research at www.researchgate.net.

Folorunso, Ewumi Azeez & Bohata, Andrea & Kavkova, Miloslava & Gebauer, Radek & Mraz, Jan. (2022). Potential use of entomopathogenic and mycoparasitic fungi against powdery mildew in aquaponics. Frontiers in Marine Science. 9. 10.3389/fmars.2022.992715. 

Publication date: Wed 9 Nov 2022