Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists identify genetic mechanism that contributed to Irish Famine

07.02.2013
Research by UC Riverside plant pathologists is the first to show that RNA silencing regulates plant defense against the notorious Phytophthora pathogens

When a pathogen attacks a plant, infection usually follows after the plant's immune system is compromised. A team of researchers at the University of California, Riverside focused on Phytophthora, the pathogen that triggered the Irish Famine of the 19th century by infecting potato plants, and deciphered how it succeeded in crippling the plant's immune system.

The genus Phytophthora contains many notorious pathogens of crops. Phytophthora pathogens cause worldwide losses of more than $6 billion each year on potato (Phytophthora infestans) and about $2 billion each year on soybean (Phytophthora sojae).

The researchers, led by Wenbo Ma, an associate professor of plant pathology and microbiology, focused their attention on a class of essential virulence proteins produced by a broad range of pathogens, including Phytophthora, called "effectors." The effectors are delivered to, and function only in, the cells of the host plants the pathogens attack. The researchers found that Phytophthora effectors blocked the RNA silencing pathways in their host plants (such as potato, tomato, and soybean), resulting first in a suppression of host immunity and thereafter in an increase in the plants' susceptibility to disease.

"Phytophthora has evolved a way to break the immunity of its host plants," Ma explained. "Its effectors are the first example of proteins produced by eukaryotic pathogens — nucleated single- or multi-cellular organisms — that promote infection by suppressing the host RNA silencing process. Our work shows that RNA silencing suppression is a common strategy used by a variety of pathogens — viruses, bacteria and Phytophthora — to cause disease, and shows, too, that RNA silencing is an important battleground during infection by pathogens across kingdoms."

Study results appeared online Feb. 3 in Nature Genetics.

What is RNA silencing and what is its significance? RNA is made from DNA. Many RNAs are used to make proteins. However, these RNAs can be regulated by "small RNA" (snippets of RNA) that bind to them. The binding leads to suppression of gene expression. Known as RNA gene silencing, this suppression plays an important role in regulating plant growth and development. When RNA silencing is impaired by effectors, the plant is more susceptible to disease.

Basic RNA silencing processes are conserved in plant and mammalian systems. They serve as a major defense mechanism against viruses in plants and invertebrates. RNA silencing has also been implicated in anti-bacterial plant defense. The discovery by Ma's lab is the first to show that RNA silencing regulates plant defense against eukaryotic pathogens.

"Phytophthora effectors have a motif or signature — a specific protein code — that allows the proteins to be delivered into host cells," Ma said. "A similar motif is found in effectors of animal parasites, such as the malaria pathogen Plasmodium, suggesting an evolutionarily conserved means for delivering effectors that affect host immunity."

Next, her lab will work on extensively screening other pathogens and identifying their effectors' direct targets so that novel control strategies can be developed to manage the diseases the pathogens cause.

Ma was joined in the study by UC Riverside's Yongli Qiao, Lin Liu, Cristina Flores, James Wong, Jinxia Shi, Xianbing Wang, Xigang Liu, Qijun Xiang, Shushu Jiang, Howard S. Judelson and Xuemei Chen; Fuchun Zhang at Xinjiang University, China; and Qin Xiong and Yuanchao Wang at Nanjing Agricultural University, China.

The research was supported by a National Science Foundation grant to Ma and grants from the U.S. Department of Agriculture (USDA) to Judelson and Chen.

In 2011, UCR received a $9 million USDA grant to research late blight, caused by Phytophthora infestans, that mainly attacks potatoes and tomatoes. Last year, UCR released avocado rootstocks that can help control Phytophthora root rot, a disease that has eliminated commercial avocado production in many areas of the world.

The University of California, Riverside is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 21,000 students. The campus will open a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion. A broadcast studio with fiber cable to the AT&T Hollywood hub is available for live or taped interviews. UCR also has ISDN for radio interviews. To learn more, call (951) UCR-NEWS.

Iqbal Pittalwala | EurekAlert!
Further information:
http://www.ucr.edu

More articles from Life Sciences:

nachricht About injured hearts that grow back - Heart regeneration mechanism in zebrafish revealed
10.02.2016 | Universität Ulm

nachricht Chemical cages: New technique advances synthetic biology
10.02.2016 | Arizona State University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The most accurate optical single-ion clock worldwide

Atomic clock experts from the Physikalisch-Technische Bundesanstalt (PTB) are the first research group in the world to have built an optical single-ion clock which attains an accuracy which had only been predicted theoretically so far. Their optical ytterbium clock achieved a relative systematic measurement uncertainty of 3 E-18. The results have been published in the current issue of the scientific journal "Physical Review Letters".

Atomic clock experts from the Physikalisch-Technische Bundesanstalt (PTB) are the first research group in the world to have built an optical single-ion clock...

Im Focus: Goodbye ground control: autonomous nanosatellites

The University of Würzburg has two new space projects in the pipeline which are concerned with the observation of planets and autonomous fault correction aboard satellites. The German Federal Ministry of Economic Affairs and Energy funds the projects with around 1.6 million euros.

Detecting tornadoes that sweep across Mars. Discovering meteors that fall to Earth. Investigating strange lightning that flashes from Earth's atmosphere into...

Im Focus: Flow phenomena on solid surfaces: Physicists highlight key role played by boundary layer velocity

Physicists from Saarland University and the ESPCI in Paris have shown how liquids on solid surfaces can be made to slide over the surface a bit like a bobsleigh on ice. The key is to apply a coating at the boundary between the liquid and the surface that induces the liquid to slip. This results in an increase in the average flow velocity of the liquid and its throughput. This was demonstrated by studying the behaviour of droplets on surfaces with different coatings as they evolved into the equilibrium state. The results could prove useful in optimizing industrial processes, such as the extrusion of plastics.

The study has been published in the respected academic journal PNAS (Proceedings of the National Academy of Sciences of the United States of America).

Im Focus: New study: How stable is the West Antarctic Ice Sheet?

Exceeding critical temperature limits in the Southern Ocean may cause the collapse of ice sheets and a sharp rise in sea levels

A future warming of the Southern Ocean caused by rising greenhouse gas concentrations in the atmosphere may severely disrupt the stability of the West...

Im Focus: Superconductivity: footballs with no resistance

Indications of light-induced lossless electricity transmission in fullerenes contribute to the search for superconducting materials for practical applications.

Superconductors have long been confined to niche applications, due to the fact that the highest temperature at which even the best of these materials becomes...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Travel grants available: Meet the world’s most proficient mathematicians and computer scientists

09.02.2016 | Event News

AKL’16: Experience Laser Technology Live in Europe´s Largest Laser Application Center!

02.02.2016 | Event News

From intelligent knee braces to anti-theft backpacks

26.01.2016 | Event News

 
Latest News

About injured hearts that grow back - Heart regeneration mechanism in zebrafish revealed

10.02.2016 | Life Sciences

The most accurate optical single-ion clock worldwide

10.02.2016 | Earth Sciences

Absorbing acoustics with soundless spirals

10.02.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>