Featured Research

from universities, journals, and other organizations

Massive gene loss linked to pathogen's stealthy plant-dependent lifestyle

Date:
December 10, 2010
Source:
Virginia Tech
Summary:
An international team of scientists has cracked the genetic code of a plant pathogen that causes downy mildew disease. Downy mildews are a widespread class of destructive diseases that cause major losses to crops as diverse as maize, grapes and lettuce.

These are pathogen-infected Arabidopsis plants.
Credit: John McDowell, Virginia Tech

An international team of scientists, which includes researchers from Virginia Tech, has cracked the genetic code of a plant pathogen that causes downy mildew disease. Downy mildews are a widespread class of destructive diseases that cause major losses to crops as diverse as maize, grapes, and lettuce.

The paper describing the genome sequence of the downy mildew pathogen Hyaloperonospora arabidopsidis, which attacks the widely studied model plant Arabidopsis thaliana, is the cover story of this week's edition of the journal Science.

In the paper, the sequence of H. arabidopsidis is compared with other fully sequenced genomes of destructive plant pathogens to shed light on the differences in the ways microbes interact with their host and how those differences evolve. The payoff could be new ways to investigate how these pathogens wreak havoc and, in the long-term, finding how to prevent billions of dollars of losses for farmers growing crops across the globe.

Downy mildew pathogens are so highly specialized for parasitizing plants that they can no longer survive away from their hosts. However, they are close cousins of pathogens such as the Sudden Oak Death pathogen Phytophthora ramorum, which can attack hundreds of forest species but can also survive away from its hosts by feeding on dead plant matter. Comparisons of the genetic sequence of H. arabidopsidis with other related plant pathogens such as P. ramorum have revealed a massive loss of genes related to the microbe's plant-dependent lifestyle.

"Some plant pathogens like H. arabidopsidis must keep their host alive throughout the infection cycle in order to survive," said Brett Tyler, professor at the Virginia Bioinformatics Institute at Virginia Tech and one of the lead authors of the study. "Others, including Phytophthora species that destroy soybean and potato crops as well as oak tree forests, keep plants alive for part of the time before killing and devouring the plant tissue. Now that we have the genome sequence for an obligate parasite member of this family of destructive pathogens, we can use that information to zero in on common genes that could be targeted to create new, widely effective disease control strategies."

Downy mildew and Phytophthora pathogens are oomycetes, fungal-like organisms that have evolved from marine algae. The availability of multiple genome sequences for oomycete plant pathogens is an important step in allowing scientists to build a picture of the host-pathogen evolutionary arms race.

"Many plant pathogens contain large families of related genes that serve as powerful weapons but can also trigger equally powerful immune responses in the plant," commented John McDowell, an associate professor in Virginia Tech's Department of Plant Pathology, Physiology, and Weed Science and one of the project's leaders. "Our comparisons across multiple genomes revealed that many of these gene families have been reduced in size or completely discarded in H. arabidopsidis. This evolution towards stealth helps explain why this mildew and its relatives are widely distributed and cause diseases on many important crops."

The H. arabidopsidis genome sequence reveals large numbers of effector proteins, the molecules that invade plant cells to suppress plant immunity. It also reveals widespread reduction in the number of genes related to degradative enzymes and other molecules linked to the metabolism of nitrogen and sulfur, which suggests that H. arabidopsidis has dispensed with many genes required for life away from the plant, instead focusing on genes that help it to stealthily take control of host cells. In fact, almost 7000 of the predicted genes in the sequence had no counterpart in the genome sequences of its less-refined Phytophthora relatives.

The massive gene loss that is evident in the H. arabidopsidis genome will provide many clues on the evolutionary adaptation necessary for a pathogen to become fully dependent on a plant host. A complete understanding of host-pathogen interactions should lead to the development of novel means of protecting crops from losses in yield caused by disease. It could also help to identify new targets for pathogen control and help in the development of novel disease-resistant varieties.

In addition, several downy mildew pathogens are listed as potential bioterror threats to agriculture in the United States. Understanding how these pathogens attack crop plants should enable preventative measures to be put in place.

The project was a collaboration involving scientists at the College of Agriculture and Life Sciences at Virginia Tech, United States, the Genome Center at Washington University, United States, The Sainsbury Laboratory, United Kingdom, the Sequencing Centre at the Wellcome Trust Sanger Institute, United Kingdom, the University of Warwick, United Kingdom, and the Virginia Bioinformatics Institute at Virginia Tech, United States. The work was supported by funds from the Agriculture and Food Research Initiative of the United States Department of Agriculture's National Institute of Food and Agriculture, and by the Emerging Frontiers program of the National Science Foundation.


Story Source:

The above story is based on materials provided by Virginia Tech. Note: Materials may be edited for content and length.


Journal Reference:

  1. Laura Baxter, Sucheta Tripathy, Naveed Ishaque, Nico Boot, Adriana Cabral, Eric Kemen, Marco Thines, Audrey Ah-Fong, Ryan Anderson, Wole Badejoko, Peter Bittner-Eddy, Jeffrey L. Boore, Marcus C. Chibucos, Mary Coates, Paramvir Dehal, Kim Delehaunty, Suomeng Dong, Polly Downton, Bernard Dumas, Georgina Fabro, Catrina Fronick, Susan I. Fuerstenberg, Lucinda Fulton, Elodie Gaulin, Francine Govers, Linda Hughes, Sean Humphray, Rays H. Y. Jiang, Howard Judelson, Sophien Kamoun, Kim Kyung, Harold Meijer, Patrick Minx, Paul Morris, Joanne Nelson, Vipa Phuntumart, Dinah Qutob, Anne Rehmany, Alejandra Rougon-Cardoso, Peter Ryden, Trudy Torto-Alalibo, David Studholme, Yuanchao Wang, Joe Win, Jo Wood, Sandra W. Clifton, Jane Rogers, Guido Van Den Ackerveken, Jonathan D. G. Jones, John M. McDowell, Jim Beynon, and Brett M. Tyler. Signatures of Adaptation to Obligate Biotrophy in the Hyaloperonospora arabidopsidis Genome. Science, 2010: Vol. 330 no. 6010 pp. 1549-1551 DOI: 10.1126/science.1195203

Cite This Page:

Virginia Tech. "Massive gene loss linked to pathogen's stealthy plant-dependent lifestyle." ScienceDaily. ScienceDaily, 10 December 2010. <www.sciencedaily.com/releases/2010/12/101209141136.htm>.
Virginia Tech. (2010, December 10). Massive gene loss linked to pathogen's stealthy plant-dependent lifestyle. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2010/12/101209141136.htm
Virginia Tech. "Massive gene loss linked to pathogen's stealthy plant-dependent lifestyle." ScienceDaily. www.sciencedaily.com/releases/2010/12/101209141136.htm (accessed October 1, 2014).

Share This



More Plants & Animals News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Attacking Superbugs

Attacking Superbugs

Ivanhoe (Oct. 1, 2014) — Two weapons hospitals can use to attack superbugs. Scientists in Ireland created a new gel resistant to superbugs, and a robot that can disinfect a room in minutes. Video provided by Ivanhoe
Powered by NewsLook.com
Cultural Learning In Wild Chimps Observed For The First Time

Cultural Learning In Wild Chimps Observed For The First Time

Newsy (Oct. 1, 2014) — Cultural transmission — the passing of knowledge from one animal to another — has been caught on camera with chimps teaching other chimps. Video provided by Newsy
Powered by NewsLook.com
Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Newsy (Sep. 30, 2014) — A new study published by the World Wide Fund for Nature found that more than half of the world's wildlife population has declined since 1970. Video provided by Newsy
Powered by NewsLook.com
Annual Dog Surfing Competition Draws California Crowds

Annual Dog Surfing Competition Draws California Crowds

AFP (Sep. 30, 2014) — The best canine surfers gathered for Huntington Beach's annual dog surfing competition, "Surf City, Surf Dog." Duration: 01:15 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins