Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gene thwarts some pathogens, gives access to others, could save crops

06.02.2006


The plant on the left is a normal laboratory test plant Arabidopsis. The plant on the right doesn’t have the gene BIK1, which helps fight off Botrytis cinerea, a pathogen that causes the gray mold disease on flowers, fruits and vegetables. Tesfaye Mengiste, a Purdue plant molecular biologist, discovered the gene and that mutant plants without it have curly leaves and shorter primary roots but more root hairs, as shown in the bottom photo. (Photos courtesy of Tesfaye Mengiste laboratory)


A single gene apparently thwarts a disease-causing invader that creates a fuzzy gray coating on flowers, fruits and vegetables. But the same gene provides access to a different type of pathogen.

A Purdue University plant molecular biologist and his collaborators in Austria and North Carolina identified the gene that helps plants recognize pathogens and also triggers a defense against disease. The gene and its defense mechanisms are similar to an immunity pathway found in people and in the laboratory research insect, the fruit fly.

As Botrytis cinerea, a pathogen that makes strawberries gray and fuzzy, tries to invade a plant, the gene BIK1 recognizes the pathogen and sets off a defensive reaction. Botrytis is a type of pathogen that can infect and obtain nutrients from dead cells on a plant and actually secretes toxic substances into plant tissue in order to gain entry. Another type of pathogen, called a biotroph, must feed on live plant cells. As a strategy to contain a pathogen, plants actually kill their own cells at the site where a biotrophic pathogen is attempting to invade.



"This gene, BIK1, makes plants resistant to pathogens such as Botrytis, but it allows biotrophic pathogens to invade," said Tesfaye Mengiste, a Purdue plant molecular biologist and assistant professor of botany and plant pathology. "The mutant plant that doesn’t have BIK1 actually shows decreased immunity to two pathogens, including Botrytis. But unexpectedly, it is completely resistant to virulent strains of the biotrophic bacteria."

The study of BIK1’s role in plant resistance to these two types of pathogens appeared in the January issue of the journal Plant Cell. The study also shows that the gene impacts plant growth and development as evidenced by abnormally short roots, overabundance of root hairs and wrinkly leaves on plants lacking the gene, according to the scientists.

The gene produces a protein located in the plant cell membranes and shows activity that is characteristic of proteins that act as enzymes. This finding led researchers to believe that these molecules give the early signals needed to set off a relay of biochemical events allowing the plant to fight off the pathogen, Mengiste said.

"Basically the BIK1 protein does this by regulating a plant defense hormone called salicylic acid," he said. "The amount of salicylic acid determines the type and level of a plant’s response to the pathogen. This is very important in terms of disease resistance.

"In this paper, we speculate that there is an optimum level of salicylic acid that is required for pathogen defense. When that level is exceeded, in some cases it may promote susceptibility to other pathogens by interfering with other defense strategies of the plants."

The research team first looked at normal plants and then at the BIK1 mutant when they began to study the effect of different hormones on plant growth and pathogen defense, Mengiste said. The scientists were surprised to find that the mutants had reduced primary root growth but increased numbers of root hairs. Along with their other findings, this revelation is leading the scientists to future research.

"It looks like this gene actually links pathogen response to plant growth and development," Mengiste said. "But how a single protein regulates these two processes that are singularly independent, we don’t know. That is the main purpose of our future studies.

"We need to figure out the details of how it regulates root growth and the length and amount of root hair. This may have implications in terms of nutrient absorption or total plant biomass."

The answers eventually could lead to increased crop yield and decreased produce loss due to Botrytis and other similar pathogens, he said.

Currently, the gray mold disease caused by Botrytis destroys about 10 percent of the grape crop annually and about 25 percent to 30 percent of tomato and strawberry crops in some seasons. It also infects many other fruits, vegetables, bulbs and a variety of flowers, including petunias, geraniums and chrysanthemums. Cool, humid weather fosters the fungus, which is spread by spores. The mold can appear in fields on growing plants and on strawberries, raspberries and other foods stored in the refrigerator.

Writer: Susan A. Steeves, (765) 496-7481, ssteeves@purdue.edu
Sources: Tesfaye Mengiste, (765) 494-0599, Mengiste@purdue.edu

Susan A. Steeves | EurekAlert!
Further information:
http://www.purdue.edu

More articles from Life Sciences:

nachricht Individual Receptors Caught at Work
19.10.2017 | Julius-Maximilians-Universität Würzburg

nachricht Rapid environmental change makes species more vulnerable to extinction
19.10.2017 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Physics boosts artificial intelligence methods

19.10.2017 | Physics and Astronomy

NASA team finds noxious ice cloud on saturn's moon titan

19.10.2017 | Physics and Astronomy

New procedure enables cultivation of human brain sections in the petri dish

19.10.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>