Featured Research

from universities, journals, and other organizations

Gene Silencing Produces Disease Resistance In Plants

Date:
November 5, 2001
Source:
University Of California - Davis
Summary:
For the first time, a technique known as "gene silencing" has produced resistance to a bacterial disease in crop plants, report researchers at the University of California, Davis.

For the first time, a technique known as "gene silencing" has produced resistance to a bacterial disease in crop plants, report researchers at the University of California, Davis.

The technique holds promise for creating genetically engineered trees and vines that can stave off crown gall, a costly disease that affects many perennial fruit and nut crops, including walnuts, apples and grapes.

Professor Abhaya Dandekar and doctoral candidate Matthew Escobar, both of the UC Davis pomology department, discovered that gene silencing can be used to interrupt the process of tumor formation in crown gall disease. Their findings will appear in the Oct. 30 issue of the Proceedings of the National Academy of Sciences.

"Gene silencing is one of the most exciting things happening in the plant sciences," said Dandekar, an authority on genetically engineered tree crops. "There have been clues that this technique might be used to produce disease resistance in plants, but we were surprised to discover just how well it actually works in the case of crown gall disease."

Crown Gall Disease

Crown gall is caused by the common soil bacterium Agrobacterium tumefacians, which has the unique ability to transfer its own DNA into the DNA of the plant it infects in a process known as "horizontal gene transfer."

The bacteria usually invade the plant at a spot where it has been wounded. The wounded plant cells release certain chemicals that make it possible for the bacterial DNA to be incorporated into the plant's DNA. Genes contained in this bacterial DNA then become active in the nuclei of the plant cells.

This molecular takeover of the plant's genetic code causes the plant to produce the proteins that trigger tumor formation. The tumors appear as galls or lumps of tissue near the base of the plant's stem. Galls can damage the plant by blocking transport of nutrients and water up and down the plant stem or tree trunk.

"This is a unique mode of parasitizing the plant," said Escobar. "By inserting a section of its own DNA into the plant's DNA, the bacteria cause the plant to form the gall, which, in turn, provides the food and shelter for production of more bacteria."

Gene Silencing

In this study, Dandekar and Escobar targeted two bacterial genes that are key to tumor formation. They used the gene-silencing technique to "turn off" those genes and prevent the galls from forming on the plants. The work was done on the tomato plant and on Arabidopsis thaliana, a small flowering plant commonly used in research.

The job of all genes is to produce proteins. Gene silencing works by interrupting or suppressing the activity of a targeted gene, preventing it from coordinating production of specific proteins. In this case, the researchers targeted the bacterial genes that cause overproduction of plant growth hormones. It is this hormonal overproduction that results in uncontrolled cell growth and gall formation.

Thus, by using the gene-silencing technique, the researchers produced genetically engineered plants that could still be infected by Agrobacterium tumefaciens but would not produce the hormones that lead to gall formation.

"Usually when you try to prevent disease, you look at stopping the bacteria or other disease-causing agents at the 'front door' and preventing them from entering the plant," said Dandekar. "Here, we're doing the opposite. We're allowing the bacteria in, then slamming the door on them."

Analytic tests indicated that there is greater than a 90 percent reduction in gall formation among the genetically engineered tomato and Arabidopsis plants. Other than the lack of galls, however, the genetically engineered plants did not look any different than their non-transgenic counterparts.

Applications for gene silencing

The researchers suggest that this gene-silencing technique will be especially useful for crops that use rootstocks -- the trunk and root portions of a plant -- on which the desired variety is grafted. Farmers use grafted rootstocks to grow many tree and vine crops.

Some day, gene silencing may be used to produce disease-resistant rootstocks for growing non-transgenic crops. The rootstocks would carry the disease-resistance traits introduced through gene silencing. The harvested crop, however, would not be genetically altered, and there would be no possibility of unintentionally transferring the foreign genes to other domestic or wild plants through pollen.

Dandekar and Escobar are now using the gene-silencing technique to produce crown-gall resistance in walnut trees.

Their research is funded by the Walnut Marketing Board of California and the University of California BioSTAR Program.


Story Source:

The above story is based on materials provided by University Of California - Davis. Note: Materials may be edited for content and length.


Cite This Page:

University Of California - Davis. "Gene Silencing Produces Disease Resistance In Plants." ScienceDaily. ScienceDaily, 5 November 2001. <www.sciencedaily.com/releases/2001/11/011105073750.htm>.
University Of California - Davis. (2001, November 5). Gene Silencing Produces Disease Resistance In Plants. ScienceDaily. Retrieved August 22, 2014 from www.sciencedaily.com/releases/2001/11/011105073750.htm
University Of California - Davis. "Gene Silencing Produces Disease Resistance In Plants." ScienceDaily. www.sciencedaily.com/releases/2001/11/011105073750.htm (accessed August 22, 2014).

Share This




More Plants & Animals News

Friday, August 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Newsy (Aug. 21, 2014) — An experimental drug used to treat Marburg virus in rhesus monkeys could give new insight into a similar treatment for Ebola. Video provided by Newsy
Powered by NewsLook.com
Terrifying City-Dwelling Spiders Are Bigger And More Fertile

Terrifying City-Dwelling Spiders Are Bigger And More Fertile

Newsy (Aug. 21, 2014) — According to a new study, spiders that live in cities are bigger, fatter and multiply faster. Video provided by Newsy
Powered by NewsLook.com
Lost Brain Cells To Blame For Sleep Problems Among Seniors

Lost Brain Cells To Blame For Sleep Problems Among Seniors

Newsy (Aug. 21, 2014) — According to a new study, elderly people might have trouble sleeping because of the loss of a certain group of neurons in the brain. Video provided by Newsy
Powered by NewsLook.com
Ramen Health Risks: The Dark Side of the Noodle

Ramen Health Risks: The Dark Side of the Noodle

AP (Aug. 21, 2014) — South Koreans eat more instant ramen noodles per capita than anywhere else in the world. But American researchers say eating too much may increase the risk of diabetes, heart disease and stroke. (Aug. 21) Video provided by AP
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:
from the past week

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