Featured Research

from universities, journals, and other organizations

Can Cancer Causing Compounds Be Cut From Tobacco? Gene 'Knockout' Floors Tobacco Carcinogen

Date:
March 19, 2008
Source:
North Carolina State University
Summary:
In large-scale field trials, scientists have shown that silencing a specific gene in burley tobacco plants significantly reduces harmful carcinogens in cured tobacco leaves. The finding could lead to tobacco products -- especially smokeless products -- with reduced amounts of cancer-causing agents. Researchers stress that the best way for people to avoid the risks associated with tobacco use is to avoid using tobacco products.

In large-scale field trials, scientists from North Carolina State University have shown that silencing a specific gene in burley tobacco plants significantly reduces harmful carcinogens in cured tobacco leaves.

The finding could lead to tobacco products – especially smokeless products – with reduced amounts of cancer-causing agents.

NC State's Dr. Ralph Dewey, professor of crop science, and Dr. Ramsey Lewis, assistant professor of crop science, teamed with colleagues from the University of Kentucky to knock out a gene known to turn nicotine into nornicotine. Nornicotine is a precursor to the carcinogen N-nitrosonornicotine (NNN). Varying percentages of nicotine are turned into nornicotine while the plant ages; nornicotine converts to NNN as the tobacco is cured, processed and stored.

The field tests in Kentucky, Virginia and North Carolina compared cured burley tobacco plants with the troublesome gene silenced and "control" plant lines with normal levels of gene expression. The researchers found a six-fold decrease in carcinogenic NNN in the genetically modified tobacco plants, as well as a 50 percent overall reduction in the class of harmful compounds called TSNAs, or tobacco-specific nitrosamines. TSNAs are reported to be among the most important tobacco-related compounds implicated in various cancers in laboratory experiments, Lewis said.

Lewis and Dewey stress that the best way for people to avoid the risks associated with tobacco use is to avoid using tobacco products. But their findings show that targeted gene silencing can work as well in the field as it does on the lab bench.

"Creating a tobacco plant with fewer or no harmful compounds may also help with tobacco plants that are being used to create pharmaceuticals or other high-value products," Dewey said.

To get initial lines of plants with the troublesome gene silenced, the NC State researchers used a technique called RNA interference in which genetic engineering was used to introduce a gene that inhibits the demethylase gene function into the tobacco plant.

Dewey and Lewis have since developed tobacco lines with the same effect without using genetic engineering. They randomly inserted chemical changes, or mutations, into the tobacco genome of burley tobacco plants. They then searched for plants in which the nicotine demethylase gene was permanently impaired. The researchers are currently working to transfer this mutation to widely used tobacco varieties.

Dewey and Lewis add that nothing else in the plant changed – growth or resistance to insects or disease, for example – after they knocked out this specific gene.

While Lewis believes that varieties of burley tobacco with a silenced demethylase gene will exist within the next few years, the NC State researchers say burley tobacco has a number of other targets for their gene silencing method.

The research is sponsored by Philip Morris USA. Philip Morris USA, a part of Altria Group, Inc., is a leading cigarette manufacturer in the U.S.

Journal reference: Ramsey S. Lewis and Ralph E. Dewey, North Carolina State University; Anne M. Jack, Lily Gavilano, Balazs Siminszky and Lowell Bush, University of Kentucky; Jerry Morris, Vincent Robert and Alec Hayes, Philip Morris USA."RNA Interference (RNAi)-Induced Suppression of Nicotine Demethylase Activity Reduces Levels of a Key Carcinogen in Cured Tobacco Leaves" Online Feb. 14 in Plant Biotechnology Journal


Story Source:

The above story is based on materials provided by North Carolina State University. Note: Materials may be edited for content and length.


Cite This Page:

North Carolina State University. "Can Cancer Causing Compounds Be Cut From Tobacco? Gene 'Knockout' Floors Tobacco Carcinogen." ScienceDaily. ScienceDaily, 19 March 2008. <www.sciencedaily.com/releases/2008/03/080318110336.htm>.
North Carolina State University. (2008, March 19). Can Cancer Causing Compounds Be Cut From Tobacco? Gene 'Knockout' Floors Tobacco Carcinogen. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2008/03/080318110336.htm
North Carolina State University. "Can Cancer Causing Compounds Be Cut From Tobacco? Gene 'Knockout' Floors Tobacco Carcinogen." ScienceDaily. www.sciencedaily.com/releases/2008/03/080318110336.htm (accessed September 1, 2014).

Share This




More Health & Medicine News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

We've Got Mites Living In Our Faces And So Do You

We've Got Mites Living In Our Faces And So Do You

Newsy (Aug. 30, 2014) A new study suggests 100 percent of adult humans (those over 18 years of age) have Demodex mites living in their faces. Video provided by Newsy
Powered by NewsLook.com
Liberia Continues Fight Against Ebola

Liberia Continues Fight Against Ebola

AFP (Aug. 30, 2014) Authorities in Liberia try to stem the spread of the Ebola epidemic by raising awareness and setting up sanitation units for people to wash their hands. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
California Passes 'yes-Means-Yes' Campus Sexual Assault Bill

California Passes 'yes-Means-Yes' Campus Sexual Assault Bill

Reuters - US Online Video (Aug. 30, 2014) California lawmakers pass a bill requiring universities to adopt "affirmative consent" language in their definitions of consensual sex, part of a nationwide drive to curb sexual assault on campuses. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
New Drug Could Reduce Cardiovascular Deaths

New Drug Could Reduce Cardiovascular Deaths

Newsy (Aug. 30, 2014) The new drug from Novartis could reduce cardiovascular deaths by 20 percent compared to other similar drugs. Video provided by Newsy
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