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 Protein Shake-Up
27.03.2015 | Oak Ridge National Laboratory

nachricht How did the chicken cross the sea?
27.03.2015 | Michigan 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: Experiment Provides the Best Look Yet at 'Warm Dense Matter' at Cores of Giant Planets

In an experiment at the Department of Energy's SLAC National Accelerator Laboratory, scientists precisely measured the temperature and structure of aluminum as...

Im Focus: Energy-autonomous and wireless monitoring protects marine gearboxes

The IPH presents a solution at HANNOVER MESSE 2015 to make ship traffic more reliable while decreasing the maintenance costs at the same time. In cooperation with project partners, the research institute from Hannover, Germany, has developed a sensor system which continuously monitors the condition of the marine gearbox, thus preventing breakdowns. Special feature: the monitoring system works wirelessly and energy-autonomously. The required electrical power is generated where it is needed – directly at the sensor.

As well as cars need to be certified regularly (in Germany by the TÜV – Technical Inspection Association), ships need to be inspected – if the powertrain stops...

Im Focus: 3-D satellite, GPS earthquake maps isolate impacts in real time

Method produced by UI researcher could improve reaction time to deadly, expensive quakes

When an earthquake hits, the faster first responders can get to an impacted area, the more likely infrastructure--and lives--can be saved.

Im Focus: Atlantic Ocean overturning found to slow down already today

The Atlantic overturning is one of Earth’s most important heat transport systems, pumping warm water northwards and cold water southwards. Also known as the Gulf Stream system, it is responsible for the mild climate in northwestern Europe. 

Scientists now found evidence for a slowdown of the overturning – multiple lines of observation suggest that in recent decades, the current system has been...

Im Focus: Robot inspects concrete garage floors and bridge roadways for damage

Because they are regularly subjected to heavy vehicle traffic, emissions, moisture and salt, above- and underground parking garages, as well as bridges, frequently experience large areas of corrosion. Most inspection systems to date have only been capable of inspecting smaller surface areas.

From April 13 to April 17 at the Hannover Messe (hall 2, exhibit booth C16), engineers from the Fraunhofer Institute for Nondestructive Testing IZFP will be...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

World Conference On Regenerative Medicine 2015: Registration And Abstract Submission Now Open

25.03.2015 | Event News

University presidents from all over the world meet in Hamburg

19.03.2015 | Event News

10. CeBiTec Symposium zum Big Data-Problem

17.03.2015 | Event News

 
Latest News

Two Most Destructive Termite Species Forming Superswarms in South Florida

27.03.2015 | Agricultural and Forestry Science

ORNL-Led Team Demonstrates Desalination with Nanoporous Graphene Membrane

27.03.2015 | Materials Sciences

Coorong Fish Hedge Their Bets for Survival

27.03.2015 | Ecology, The Environment and Conservation

VideoLinks
B2B-VideoLinks
More VideoLinks >>>