Feeds:
Posts
Comments

Archive for the ‘Nematodes’ Category

fresh plaza logo

WSU researchers combat parasitic worm

Plants that fight back

So small it can’t be seen with the naked eye, a parasitic worm called the root-knot nematode causes mammoth problems for Northwest farmers. But potatoes, grapes and other crops could gain a new, nature-based way to fight back, thanks to Cynthia Gleason and Jennifer Watts, scientists at WSU.

Notorious thieves
Nematodes cause billions of dollars in crop losses nationwide every year. In Washington, they cause significant losses to crops such grapes, onions, garlic and the state’s $734 million potato industry.

“Root-knot nematodes are a huge problem for farmers,” said Gleason, plant pathologist with WSU’s College of Agricultural, Human and Natural Resource Sciences (CAHNRS). The soilborne parasites move into the roots of crops, “then just sit there and feed on the plant. They’re stealing nutrients and water.”

Nematodes don’t kill the plants, but they leave them stunted, wilted from lack of water, and more susceptible to other pathogens, ultimately reducing farmers’ yields.

Chemical-free weapon pursued
“Plants don’t have many natural resistances to root-knot nematodes, so we need a way to combat them,” Gleason said. Traditionally, farmers have used anti-nematode pesticides -nematicides- to eliminate the tiny worms.

“But there aren’t many chemical options left, and they’re very expensive,” she said. “I’m looking for new, chemical-free controls that help growers move on.”

Acid stops nematodes
To help, Gleason is using a new $47,400 Emerging Research Issues grant from the CAHNRS Office of Research to seek genetic defenses that help crops like potatoes and tomatoes fight back against the persistent pest. “I’m developing plants that are basically toxic to nematodes,” she said.

Jennifer Watts, researcher in the School of Molecular Biosciences, discovered that a dietary fatty acid stops parasites from multiplying. Partnering with Jennifer Watts, researcher in the College of Veterinary Medicine’s School of Molecular Biosciences, Gleason is adding genes that tell plants to secrete a specific fatty acid that stops the nematode reproductive cycle.

Watts and her team of student researchers discovered that a certain fatty acid, referred to as DGLA (20:3n-6), stops egg production in a cousin species of the root-knot nematode.

“These fatty acids aren’t normally produced in plant tissue,” says Watts. “My team and I are working with Cynthia to introduce genes into plants so they can make them. If it works, it could be a new, chemical-free method to control nematodes.”

While the fatty acid is not known to be toxic to people or animals at low levels, the researchers plan to only express it in cover crops and plant tissues that aren’t normally eaten.

Future pest fighters
Farmers could one day plant a seed, Gleason said, that grows into a cover or cash crop with its own natural pest control. As nematodes feed on the plants, their populations will fall — leading to healthier plants, bigger crops and an improved food supply.

“Usually, the study of nematodes and the challenges they bring is about new chemicals and pesticide controls,” said Gleason. “This is a new and different approach, one that’s chemical free.

“By working across colleges, mine and Jennifer’s teams are discovering and accomplishing much more than we could individually,” she added. “We can use that information to fight parasites, help Washington farmers, and grow more food. It’s a collaboration that benefits everyone.”

For more information:

Washington State University
Cynthia Gleason
Department of Plant Pathology
Tel.: +1 509-335-3742
Jennifer Watts
School of Molecular Biosciences
Tel.: +1 509-335-8554

 

Publication date: 6/21/2018

 

Read Full Post »

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.

 

 

Read Full Post »

PHYS/ORG

Deciphering plant immunity against parasites

April 13, 2017

Deciphering plant immunity against parasites
These researchers are from the Department of Molecular Phytomedicine at the University of Bonn. Credit: Molekulare Phytomedizin/Uni Bonn

Nematodes are a huge threat to agriculture since they parasitize important crops such as wheat, soybean, and banana; but plants can defend themselves. Researchers at Bonn University, together with collaborators from the Sainsbury Laboratory in Norwich, identified a protein that allows plants to recognize a chemical signal from the worm and initiate immune responses against the invaders. This discovery will help to develop crop plants that feature enhanced protection against this type of parasites. The work is published in the current issue of PLoS Pathogens.

 

Plant-parasitic nematodes are microscopic worms that parasitize their to withdraw water and nutrients. The feeding process seriously damages the host plant. Nematode infection distorts root and shoot structure, compromises the plant´s ability to absorb nutrients from soil, and eventually reduces crop yield. Yearly losses exceed ten percent in important such as wheat, soybean, and banana. In addition to causing direct damage, nematode infection also provides an opportunity for other pathogens to invade and attack the host plants.

Until now, near to nothing was known about the general innate of plants against nematodes. A team of researchers at the University of Bonn, in cooperation with scientists from the Sainsbury Laboratory in Norwich, has now identified a gene in thale cress (Arabidopsis thaliana), called NILR1, that helps plants sense nematodes. “The NILR1 is the genetic code for a receptor protein that is localized to the surface of plant cells and is able to bind and recognize other molecules,” says Prof. Florian Grundler, chair at the Department of Molecular Phytomedicine at the University of Bonn. “NILR1 most probably recognizes a molecule from nematodes, upon which, it becomes activated and immune responses of plants are unleashed.”

NILR1 recognizes a broad spectrum of nematodes

Although a few receptors, so-called resistance genes, providing protection against specific types of plant-parasitic nematodes have already been identified, NILR1 recognizes rather a broader spectrum of nematodes. “The nice thing about NILR1 is that it seems to be conserved among various and that it provides protection against many nematode species,” says group leader Dr. Shahid Siddique. “The discovery of NILR1 also raises questions about the nematode derived molecule, whose recognition is thought to be integral to this process.” Now that an important receptor is discovered, the scientists are working to find the molecule which binds to NILR1 to switch on the immune responses. The two first authors, PhD students at the department share tasks in the project. Whereas Mary Wang´ombe focuses on the receptor protein and its function, Badou Mendy concentrates on isolating the signal molecule released by the nematodes.

New options for breeding resistant crop plants

The findings of the University Bonn Scientists open new perspectives in making crops more resistant against nematodes. They could already show that important crop plants such as tomato and sugar beet also possess a functional homologue of NILR1 – an excellent basis for further specific breeding. Once the nematode signal is characterized, a new generation of natural compounds will be available that is able to induce defense responses in thus paving the way for safe and sustainable control.

Explore further: Researchers discover a new link to fight billion-dollar threat to soybean production

More information: Mendy, B., Wang’ombe, M.W., Radakovic, Z., Holbein, J., Ilyas, M., Chopra, D., Holton, N., Zipfel, C., Grundler, F.M.W., and Siddique, S.: Arabidopsis leucine-rich repeat receptor-like kinase NILR1 is required for induction of innate immunity to parasitic nematodes, PLoS Pathogens, Internet: doi.org/10.1371/journal.ppat.1006284

Read more at: https://phys.org/news/2017-04-deciphering-immunity-parasites.html#jCp

Read Full Post »

http://www.oired.vt.edu/ipmil/ipm-il-finds-sterile-soil-rice-damaging-nematode-cambodia/#more-6474

When Jon Eisenback, professor of plant nematology at Virginia Tech’s College of Agriculture and Life Sciences, conducted nematode surveys on vegetables and rice in Cambodia this past August, one of the most surprising things he encountered in the vegetable fields was, in a word, nothing.

“One of the biggest finds from that trip was almost completely sterile soil,” Eisenback said of the surveys he and postdoctoral associate Paulo Viera conducted in vegetable farms near Siem Reap.

They visited farms growing cucumbers, sweet melons, eggplants, tomatoes, and cantaloupes to assess whether any of them were suffering from nematode invasions, but they found that all the crops were grown under plastic with drip irrigation. They had been covered with so many pesticides that there was nearly nothing living – the soil was essentially ruined.

cambodia-survey-768x512

Jon Eisenback, second from right, professor of plant nematology at Virginia Tech’s College of Agriculture and Life Sciences, testing soil in the fields of Cambodia with postdoctoral associate Paulo Viera, second from left.

Plant parasitic nematodes are microscopic roundworms that cause significant damage to many crops. In Cambodia, a country with nearly half of its labor force in agriculture, nematodes can create big problems for food production.

To control the pest, Eisenback and Viera traveled to Cambodia to survey nematodes for two IPM Innovation Lab Projects: Rice IPM for Cambodia and Vegetable crops and mango IPM in Asia.

Because of our program’s focus on biocontrol and biopesticides to alleviate agricultural pest problems, Eisenback said that the vegetable IPM project would increase chances that vegetable farmers in Cambodia would stop the soil-killing overuse of pesticides.

After surveying the vegetable fields in the north, Eisenback and Viera traveled to the south of the country to conduct nematode surveys on rice. Given the dearth of scientific literature published on nematodes in Cambodia relating to rice, Eisenback and Viera weren’t sure what to expect. However, they found that the rice fields they surveyed showed a significant loss of production caused by the rice root nematode.

“Every root we looked at had lesions,” Eisenback said. The culprit was a parasitic nematode called Hirschmanniella mucronata. “Rice roots should be creamy white. These were speckled with brown and orange lesions.”

Eisenback expects that these nematodes could cause a 20 to 30 percent crop loss of rice in affected fields.

The next step is field demonstrations; to undertake them, half the fields should be treated with nematicide to measure the effect. Eisenback also said he hopes to continue the survey to see what other nematodes are there.

“I would suspect that there are other fields with other nematode problems.”

As for the vegetable fields with the sterile soil near Siem Reap, Eisenback offered a recommendation for them as well: Don’t use so many toxic pesticides.

With IPM IL’s projects up and running in the region, that should soon become less of a problem.

Read Full Post »

 

d2549-1

A juvenile root-knot nematode, Meloidogyne incognita, penetrates a tomato root. Once inside, the juvenile, which also attacks cotton roots, causes a gall to form and robs the plant of nutrients. Photo by William Wergin and Richard Sayre. Colorized by Stephen Ausmus.

19th Biennial Group Meeting of the “All India Coordinated Research Project (AICRP) on Nematodes in Cropping Systems”

 At the 19th Biennial Group Meeting of the “All India Coordinated Research Project (AICRP) on Nematodes in Cropping Systems” recently held at University of Agricultural and Horticultural Sciences, Shivamogga (Karnataka) India; experts from the country conveyed that an aggressive (with high reproduction rate, more damage to host plants and wide host range) root knot nematode, Meloidogyne enterolobii,  got introduced and established through guava root stocks from Chhattisgarh, is causing huge losses in Dindigul, Coimbatore, Villupuram, Dharampuri and Krishnagiri districts of Tamil Nadu.  The group emphasized that there is an urgent need to strengthen and enforce domestic quarantine mechanism to suspend spread of plant parasitic nematodes with vegetative propagules, especially through seed potatoes and rooted plants – along with soil, from nurseries/ sick plots/ hot-spot areas to disease free niches. In their opinion, presently nurseries in the country are having a field day and incorrigible for spreading pests without meeting any cleanliness standards or phytosanitary regulations. To break the pathway,  it was suggested to enforce registration and licensing of plants and horticultural nurseries.

The recommendation from the Biennial Workshop is immensely important for reducing crop losses of horticultural crops in the country. Horticulture plant nurseries are extremely complex agricultural systems, recorded as pathways for several pests and diseases. Dr. Rajan said that the situation has become further cumbersome with ‘on line’ availability and sale of live ornamental and horticultural plants in the country. As disease management in nurseries/ green houses require specialisation; nematologists from the group ventured a draft road map – with details of detection, exclusion, risk analysis, critical control points for nursery stocks, infrastructure required for prophylactic measures, and costs involved for a prophylactic holistic system approach for registration/ certification for Nurseries and Green Houses.

In the address, Dr. D. J. Patel (Former Dean, Anand Agriculture University) and Dr. P. P. Reddy (Former Director, Indian Institute of Horticulture Research), well known experts in the subject expressed deep concerns about new nematode diseases in pomegranate, guava, coconut, banana, spices and vegetables all over the country through propagules. There is urgent need for policy support from Indian Council of Agricultural Research (ICAR), Department of Agriculture and Cooperation as well as Horticulture Mission for framing mandatory regulatory provisions for registration, licensing and certification of protected cultivation houses, nurseries and green houses especially for pest / quarantine requirements.

Dr. R. K. Walia, Project Coordinator (Nematodes), presented a brief history, background and the salient achievements of the AICRP on nematodes and overall scenario Plant Nematology research in India. He expressed serious concerns about the losses in crops due to nematode diseases and urged upon the nematologists to devise integrated approaches to manage root knot nematode (Meloidogyne spp.) problem in recently established poly-houses (for promoting cultivation of vegetables and ornamental) all over the country.

New publications “Pictorial guide on important nematode diseases of Karnataka”, “Comprehensive monograph of rice root-knot nematode (Meloidogyne graminicola)”, “Status of plant nematode diseases in Karnataka – a review”, and “Compendium of new plant parasitic nematode diseases of Karnataka”, along with a number of bulletins on serious issues were also launched on the occasion.

Rajan 

Principal Scientist (Plant Protection)

Crop Science Division,

Indian Council of Agricultural Research,

Krishi Bhawan, New Delhi 110001, India

email: rajan.newdelhi@gmail.com

Telefax: 011-23382385

Read Full Post »

Nematode pheromone ascr#18 has been shown to alert plants to the presence of plant-parasitic nematodes and to activate their immune responses.

Nematodes, or roundworms, are the most numerous animals on earth, parasitizing most plants and animals. These infections are responsible for many of the most common neglected tropical diseases, causing significant morbidity and mortality. Soil-dwelling nematodes also put food security at risk by attacking agriculturally important plants. While the human response to dealing with parasite infection has been thoroughly researched; it has only recently been discovered that plant-parasitic nematodes not only activate defensive responses in plants, but also provide nematode-mediated immunity to subsequent attack by pathogens and viruses.

Numerous nematodes

Root-knot nematode galls on plant roots. Source: commons wikimedia
Root-knot nematode galls on plant roots. Source: commons wikimedia

Despite more than 4,100 species of plant-parasitic roundworms being identified, two major groups of nematodes are responsible for most agricultural plant damage. The root-knot nematodes, Meloidogyne spp. damage plants by producing galls on roots; whereas, the cyst nematodes, Heterodera and Globodera spp., by the formation of root cysts.

Soil-dwelling nematodes are ubiquitous and rich arable soil may contain up to 3 billion worms per acre. It therefore comes as no surprise that infected crops result in over $100 billion worth of agricultural damage globally per annum. For British crops alone, damage by cyst nematodes, Globodera rostochiensis and G. pallida, account for an estimated  £50 million damage each year.

Cyst nematodes damage to potato roots. Source: commons wikimedia

Cyst nematodes damage to potato roots. Source: commons wikimedia

Nematode control therefore is a serious business; however, following the current tightening of legislation, withdrawal from use of inorganic pesticides (the primary source of pest and disease management over the past decades) and a lack of resistant plant varieties, there is an urgent need to understand more about plant natural defenses to promote resistance to nematodes and other invaders.

Plant defenses against pathogens

Plant defenses can be broadly grouped into constitutive (continuous) defenses and inducible defenses. Toxic chemicals or defense-related proteins are typically only produced after pathogens are detected due to the high energy costs associated with their production and maintenance. To allow detection of, and rapid response to, potentially harmful pathogens plants have evolved several layers of highly developed surveillance mechanisms to try and circumvent serious damage.

The first line of defense consists of inducible defenses, which are mounted when plant cells recognize microbe-associated molecular patterns (MAMPs), such as lipopolysaccharides, flagellin, peptidoglycan and other compounds commonly found in microbes. Plant cells then become fortified against attack, conferring protection from the invading pathogen. Although MAMP’s have been well characterized, up until recently, it remained unclear as to whether plants could detect conserved molecular patterns derived from plant-parasitic animals, such as soil-dwelling nematodes.

‘Nematode-associated molecular patterns’

A number of studies have previously shown that, in response to plant-parasitic nematode infection, plants quickly activate defense pathways similar to those induced by other pathogens. Although these findings were very promising, what the nematode-derived signals actually were remained a mystery.

Following the discovery that non-parasitic soil nematodes can also induce plant defenses, a conserved nematode signature molecule appeared to be a likely trigger for activating the plant defense response. Ascarosides are pheromones exclusive to nematodes that are used to regulate development and social behaviours. Ascarosides represent an evolutionarily conserved family of signalling molecules, of which more than 200 different ascaroside structures from over 20 different species have been identified. Due to the highly conserved nature of these molecules, it seemed plausible that plant hosts and nematode-associated microorganisms may have evolved the means to detect and respond to this ancient nematode molecule. A recent study published in Nature Communications investigated whether ascarosides can be detected by plants, and whether detection of the molecules induced the plant-defence response.

(a) Examples of ascarosides previously identified. (b) HPLC-MS analysis of nematode exo-metabolome samples, showing seven detected ascarosides. (c) Chemical structures of identified ascarosides and relative quantitative distribution. Source: http://www.nature.com/ncomms/2015/150723/ncomms8795/fig_tab/ncomms8795_F1.html
(a) Examples of ascarosides previously identified. (b) HPLC-MS analysis of nematode exo-metabolome samples, showing seven detected ascarosides. (c) Chemical structures of identified ascarosides and relative quantitative distribution. Source: http://www.nature.com/ncomms/2015/150723/ncomms8795/fig_tab/ncomms8795_F1.html

Profiles of ascarosides from adult and juvenile stages of a number of agriculturally relevant species of plant-parasitic nematodes were characterised using mass spectrometry (MS) to analyse the metabolome excreted into media supernatant. MS analysis of exo-metabolome samples revealed excretion of similar sets of ascarosides in all analysed species; however, ascr#18 was identified in all plant-parasitic nematodes as the most abundant molecule.

In order to determine whether ascr#18 could be perceived by plants and influence plant-defensive responses to different pathogens, the ascaroside was applied in various concentrations to Arabidopsis roots 24 h prior to leaf innoculation with pathogens. By monitoring expression of MAMP-triggered immunity (MTI) markers and defense-related genes in leaves at different time points after root treatment with ascr#18, characteristic defense responses such as MAMP-triggered immunity were shown to be induced. Interestingly, local and systemic defenses were also shown to be activated by ascr#18 application to leaves.

Detection of ascr#18 by plants increased resistance to viral, bacterial, oomycete, fungal and nematode infections in Arabidopsis, as well as tomato, potato and barley. Additionally, three other ascarosides applied to different plants showed defense responses were induced by structurally diverse ascarosides, but that this varied in a structure- and species-dependent manner.

Conclusions

A comparison of experimental wheat lines showing different levels of resistance to the disease spot blotch. Source: https://www.flickr.com/photos/cimmyt/6508078617
A comparison of experimental wheat lines showing different levels of resistance to the disease spot blotch.                                                                                                                                                                                                                                                                            Source: https://www.flickr.com/photos/cimmyt/6508078617

Plant crops suffer  considerable damage every year from parasites and pathogens, putting food security at great risk. The ability to activate plant immune responses as and when required by using signalling molecules, such as ascarosides, is an exciting discovery that could contribute to improving the economic and environmental sustainability of agriculture. One potential application could be spraying of ascr#18 on crop leaves; as although plants primarily encounter ascarosides via their roots, leaf exposure to low ascr#18 concentrations was also effective at inducing the defense responses to confer fortification against attack.

Read Full Post »

feed the future logo-feed-the-future

Ubaldo Sagastume in his coffee field

Partnering for Innovation
Country: Honduras
Award period:April 2015 – January 2017
Website: http://www.zamorano.edu
With foreign markets requiring reductions in the use of chemicals, there is great demand for biological solutions to pest management. Zamorano University will promote the use of beneficial nematodes instead of traditional pesticides to control insect infestations in select horticultural crops. Through scale-up of their biocontrol laboratory, Zamorano will produce and sell 20 times as many doses of beneficial nematodes over the previous year. Small producers will be able to access this biocontrol at a much lower cost than a synthetic chemical product throughout the western departments of Honduras.

Outcome: 9,000 hectares of smallholder land will use biological pest control. In addition, Zamorano will sell through a commercial partner to build a sustainable distribution channel in the country.

See: http://partneringforinnovation.org/program-zamorano-university.aspx

Read Full Post »

Older Posts »