Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Blunting rice disease


UD researchers aim to disarm a 'cereal killer'

A fungus that kills an estimated 30 percent of the world’s rice crop may finally have met its match, thanks to a research discovery made by scientists at the University of Delaware and the University of California at Davis.

UD researchers Harsh Bais, Carla Spence (left) and Nicole Donofrio examine rice plants. They have identified a naturally occurring microbe in soil that inhibits the devastating rice blast fungus.

The research team, led by Harsh Bais, associate professor of plant and soil sciences in UD’s College of Agriculture and Natural Resources, has identified a naturally occurring microbe living right in the soil around rice plants — Pseudomonas chlororaphis EA105 — that inhibits the devastating fungus known as rice blast. What’s more, the beneficial soil microbe also induces a system-wide defense response in rice plants to battle the fungus.

The research, which is funded by the National Science Foundation, is published in BMC Plant Biologyand includes, along with Bais, authors Carla Spence, a doctoral student in the Department of Biological Sciences, Emily Alff, who recently earned her master’s degree in plant and soil sciences, and Nicole Donofrio, associate professor of plant and soil sciences, all from UD; and SundaresanVenkatesan, professor, Cameron Johnson, assistant scientist, and graduate student Cassandra Ramos, all from UC Davis. 

“We truly are working to disarm a ‘cereal killer’ and to do so using a natural, organic control,” says Bais, in his laboratory at the Delaware Biotechnology Institute. In addition to rice, a distinct population of the rice blast fungus also now threatens wheat production worldwide.

“Rice blast is a relentless killer, a force to be reckoned with, especially as rice is a staple in the daily diet of more than half the world’s population — that’s over 3 billion people,” Bais notes. “As global population continues to grow, biocontrol bacteria may be an important key for farmers to overcome crop losses due to plant disease and to produce more food from the same acre of land.”

According to Bais, the rice blast fungus (Magnaporthe oryzae) attacks rice plants through spores resembling pressure plugs that penetrate the plant tissue. Once these spores infiltrate the cell wall, the fungus “eats the plant alive,” as Bais says. Common symptoms of rice blast are telltale diamond shaped-lesions on the plant leaves.

In order to do its work, the spore must produce a structure called the appressorium, a filament that adheres to the plant surface like an anchor. Without it, the fungus can’t invade the plant.

In a research study published in the journal Planta this past October, Bais and colleagues Spence, Donofrio and Vidhyavathi Raman showed that Pseudomonas chlororaphis EA105 strongly inhibited the formation of the appressorium and that priming rice plants with EA105 prior to infection by rice blast decreased lesion size.

For her work, Spence, the lead author, recently received the Carson Best Paper Award for the best scientific paper published by a Ph.D. student in biological sciences at UD. 

The next step in the research was to sample the rhizosphere, the soil in the region around the roots of rice plants growing in the field, to reveal the microbial community living there and to attempt to elucidate their roles.

Thanks to DNA sequencing techniques, Bais says that identifying the various microorganisms in soil is easy. But understanding the role of each of those microorganisms is a continuing story.

A natural control for a deadly fungus

“Everyone knows what’s there, but we don’t know what they are doing,” Bais says of the microbes. To home in on the source of the antifungal impact, Bais and his colleagues are relying on what he refers to as “old school culturing” to find out if a single bacterium or a group of different bacteria are at work.

In their study reported in BMC Plant Biology, the researchers used gene sequencing techniques to identify 11 naturally occurring bacteria isolated from rice plants grown in the field in California. These bacteria were then tested in the laboratory, with Pseudomonas chlororaphis EA105 demonstrating the strongest impact on rice blast. The soil microbe reduced the formation of the anchor-like appressoria by nearly 90 percent while also inhibiting fungal growth by 76 percent. 

Bais points out that although hydrogen cyanide is commonly produced by pseudomonad bacteria, the antifungal impact of Pseudomonas chlororaphis EA105 appears to be independent of cyanide production. 

Applying a natural soil microbe as an antifungal treatment versus chemical pesticides offers multiple benefits to farmers and the environment, Bais says. 

“Rice blast quickly learns how to get around synthetics — most manmade pesticides are effective only for about three years,” Bais says. “So it’s really cool to find a biological that can attenuate this thing.” 

Bais, who also has conducted multiple studies with beneficial microbes in the Bacillus family, envisions a day when farmers will treat plants with a “magic cocktail of microbes” naturally found in soil to help boost their immunity and growth. 

This summer, he and his colleagues will conduct field trials using Pseudomonas chlororaphis EA105 on rice plants grown on the UD farm. He also will work with farmers in the central states in India.

The research is supported by a $1.9 million grant from the National Science Foundation’s Plant Genome Research Project.

Article by Tracey Bryant

Photo by Kathy F. Atkinson

Donna O'Brien | Eurek Alert!
Further information:

Further reports about: BMC Bais Delaware Pseudomonas antifungal bacteria farmers formation fungus microbe microbes pesticides spores

More articles from Life Sciences:

nachricht Two decades of training students and experts in tracking infectious disease
27.11.2015 | Hochschule für Angewandte Wissenschaften Hamburg

nachricht Increased carbon dioxide enhances plankton growth, opposite of what was expected
27.11.2015 | Bigelow Laboratory for Ocean Sciences

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Climate study finds evidence of global shift in the 1980s

Planet Earth experienced a global climate shift in the late 1980s on an unprecedented scale, fuelled by anthropogenic warming and a volcanic eruption, according to new research published this week.

Scientists say that a major step change, or ‘regime shift’, in the Earth’s biophysical systems, from the upper atmosphere to the depths of the ocean and from...

Im Focus: Innovative Photovoltaics – from the Lab to the Façade

Fraunhofer ISE Demonstrates New Cell and Module Technologies on its Outer Building Façade

The Fraunhofer Institute for Solar Energy Systems ISE has installed 70 photovoltaic modules on the outer façade of one of its lab buildings. The modules were...

Im Focus: Lactate for Brain Energy

Nerve cells cover their high energy demand with glucose and lactate. Scientists of the University of Zurich now provide new support for this. They show for the first time in the intact mouse brain evidence for an exchange of lactate between different brain cells. With this study they were able to confirm a 20-year old hypothesis.

In comparison to other organs, the human brain has the highest energy requirements. The supply of energy for nerve cells and the particular role of lactic acid...

Im Focus: Laser process simulation available as app for first time

In laser material processing, the simulation of processes has made great strides over the past few years. Today, the software can predict relatively well what will happen on the workpiece. Unfortunately, it is also highly complex and requires a lot of computing time. Thanks to clever simplification, experts from Fraunhofer ILT are now able to offer the first-ever simulation software that calculates processes in real time and also runs on tablet computers and smartphones. The fast software enables users to do without expensive experiments and to find optimum process parameters even more effectively.

Before now, the reliable simulation of laser processes was a job for experts. Armed with sophisticated software packages and after many hours on computer...

Im Focus: Quantum Simulation: A Better Understanding of Magnetism

Heidelberg physicists use ultracold atoms to imitate the behaviour of electrons in a solid

Researchers at Heidelberg University have devised a new way to study the phenomenon of magnetism. Using ultracold atoms at near absolute zero, they prepared a...

All Focus news of the innovation-report >>>



Event News

Fraunhofer’s Urban Futures Conference: 2 days in the city of the future

25.11.2015 | Event News

Gluten oder nicht Gluten? Überempfindlichkeit auf Weizen kann unterschiedliche Ursachen haben

17.11.2015 | Event News

Art Collection Deutsche Börse zeigt Ausstellung „Traces of Disorder“

21.10.2015 | Event News

Latest News

Siemens to supply 126 megawatts to onshore wind power plants in Scotland

27.11.2015 | Press release

Two decades of training students and experts in tracking infectious disease

27.11.2015 | Life Sciences

Coming to a monitor near you: A defect-free, molecule-thick film

27.11.2015 | Materials Sciences

More VideoLinks >>>