Navigation Links
Scientists identify genetic mechanism that contributed to Irish Famine

RIVERSIDE, Calif. 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.


Contact: Iqbal Pittalwala
University of California - Riverside

Related biology news :

1. Scientists turn toxic by-product into biofuel booster
2. Scientists find a key element of lupus, suggesting better drug targets
3. Scientists notch a win in war against antibiotic-resistant bacteria
4. Plant scientists at CSHL demonstrate new means of boosting maize yields
5. Listening to cells: Scientists probe human cells with high-frequency sound
6. A*STAR scientists solve century-old mystery by finding stable haploid strains of Candida albicans
7. Joslin scientists find first human iPSC from patients with maturity onset diabetes of the young
8. Scientists uncover previously unknown mechanism of memory formation
9. Scientists trick iron-eating bacteria into breathing electrons instead
10. Damon Runyon Cancer Research Foundation grants prestigious awards to 17 young scientists
11. Virginia Tech computer scientists develop new way to study molecular networks
Post Your Comments:
Related Image:
Scientists identify genetic mechanism that contributed to Irish Famine
(Date:4/13/2017)... SANTA MONICA, Calif. , April 13, 2017 /PRNewswire/ ... New York will feature emerging and ... Innovation Summits. Both Innovation Summits will run alongside the ... variety of speaker sessions, panels and demonstrations focused on ... east coast,s largest advanced design and manufacturing event will ...
(Date:4/11/2017)... 11, 2017 No two people are ... the New York University Tandon School of Engineering ... found that partial similarities between prints are common ... mobile phones and other electronic devices can be ... vulnerability lies in the fact that fingerprint-based authentication ...
(Date:4/5/2017)... April 5, 2017 Today HYPR Corp. ... the server component of the HYPR platform is officially ... the end-to-end security architecture that empowers biometric authentication across ... has already secured over 15 million users across the ... of connected home product suites and physical access represent ...
Breaking Biology News(10 mins):
(Date:10/10/2017)... (PRWEB) , ... October 10, 2017 , ... Dr. Bob ... at his local San Diego Rotary Club. The event entitled “Stem ... CA and had 300+ attendees. Dr. Harman, DVM, MPVM was joined by two ...
(Date:10/10/2017)... ... October 10, 2017 , ... The Pittcon ... awards honoring scientists who have made outstanding contributions to analytical chemistry ... Pittcon 2018, the world’s leading conference and exposition for laboratory science, which will ...
(Date:10/9/2017)... Phoenix, Arizona (PRWEB) , ... October 09, 2017 ... ... of Kindred, a four-tiered line of medical marijuana products targeting the needs of ... production and packaging of Kindred takes place in Phoenix, Arizona. , As operators ...
(Date:10/7/2017)... , Oct. 6, 2017  The 2017 ... of three scientists, Jacques Dubochet, Joachim Frank ... developments in cryo-electron microscopy (cryo-EM) have ... within the structural biology community. The winners worked ... can now routinely produce highly resolved, three-dimensional images ...
Breaking Biology Technology: