News release issued January 3, 2001, effective immediately
For media inquiries, contact Caroline Booth Lara, Communications Specialist, (580) 224-6379.

Small Arabidopsis Makes Big Hit in Science World

Arabidopsis: It’s such a small and common plant, a member of the mustard family that can be found practically anywhere on the globe. Who would have thought it would make such a huge splash in the scientific world, worldwide?

Researchers recently finished "unraveling" the structure of the plant’s entire genetic code (genome) at the DNA level. The competed analysis of the Arabidopsis genome sequencing effort was formally announced Dec. 13, 2000, with a White House reception and the December edition of Plant Physiology journal focusing on Arabidopsis research. And the announcement is being felt far away from Washington, D.C., in laboratories at the Noble Foundation in Ardmore, Okla.

Several plant biologists at the Noble Foundation use Arabidopsis as a model plant for their research, and news of the completion of the genome sequencing project provides new opportunities, they say

"Most of the labs here use information from Arabidopsis at some level," said staff scientist Dr. Maria J. Harrison. "This (completing the Arabidopsis genome map) speeds up research in all plant species, especially those areas of plant biology common to Arabidopsis and other plant species, such as flowering or seed development."

Another model plant used for research at NF is Medicago truncatula. This species is widely used for research on biological reactions and interactions that do not occur in Arabidopsis. The NF Plant Biology Division recently created the Center for Medicago Genomics Research, an M. truncatula genomics program coordinated by Dr. Gregory D. May. The program involves an approach that provides information about the "active part" of the M. truncatula genome.

Harrison said a meeting will be held in San Diego later this month to discuss progress with M. truncatula genomics. Included at the meeting will be discussions of the potential sequencing of the Medicago truncatula genome. Research groups involved in Medicago genomics are located primarily in Europe and the United States. In the U.S., these programs are funded by The National Science Foundation and The Samuel Roberts Noble Foundation.

Plant Biology Director Richard A. Dixon was equally pleased about the Arabidopsis news, and how it relates to the NF laboratories.

"The beauty of it is that Arabidopsis gets you to where you are going with your lab work very quickly," due to the simplicity of the plant’s genomic makeup, Dixon said. For his lab, that means two areas of research made easier.

First, Dixon said, Arabidopsis has always proven to be an excellent "background" plant onto which new sequences of biochemical reactions known as "pathways" can be inserted, or "pasted." In his lab, these pathways include cancer-preventing substances known as isoflavones. When a pathway is pasted into a "clean" plant such as Arabidopsis through genetic engineering, scientists can observe if the pathway works, and by that judge whether they have identified all the pieces and properties required for that pathway.

Second, he said, the small member of the mustard family is frequently used by his lab in isolating genes in disease resistance.

In Harrison’s lab, Arabidopsis is used to study the ways in which plants take up phosphate from the soil and how it moves around the plant. Although the completion of the Arabidopsis program is just being announced, the groups conducting the mapping program have been releasing information from their findings for several years.

"We identified some new phosphate transporters some time ago by analyzing it (the released Arabidopsis information) on the Web. It is possible to find them based on sequence similarity to known transporters," Harrison said. Her lab has been using the plant for the past five years or more to study phosphate transport, but has been dealing with M. truncatula even longer. Arabidopsis does not lend itself to analysis of the arbuscular mycorrhizoid symbiosis, one of her main areas of research.

"Arabidopsis is the basic model plant without many of the extra features found in other plants. Its simple genome has made it ideal for many projects," Harrison said.

Scientists from Japan, Europe and the U.S. decided to sequence the Arabidopsis genome five years ago, "to provide access to a wealth of new information on plant biology," according to an article in Nature, the scientific journal that for the first time published an entire plant genome sequence in its Dec. 14-released edition.

The genome sequence includes nearly 26,000 genes. Of those, it’s estimated less than 10 percent of Arabidopsis genes have been studied so far, and the mapping has revealed several new genes as well.

Scientists will be better able to study plant metabolic systems and how they react to their environment, and how they cope with pests and disease. Research can be better facilitated on crop plants, and in identifying and engineering important agronomic characteristics into crops and forages as well.

Interestingly enough, studies in other labs have revealed that Arabidopsis has almost twice as many genes as the fruit fly – a fact that surprises many people, who assume plants are much simpler organisms.

"In some respects, the completion of the Arabidopsis genome sequence will have as great, or greater, long term impact on humankind than the completion of the human genome sequence," Dixon said.

"Plants are our major source of oxygen, food, fiber and drugs. As the world population continues to increase, this provision will be the most critical factor for our existence on the planet. Having the complete genetic makeup of a plant at our fingertips will greatly accelerate our understanding of how to manipulate plants to address our needs."

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Photos: Dr. Rick Dixon | Dr. Maria Harrison | Dr. Greg May

The Samuel Roberts Noble Foundation, headquartered in Ardmore, Okla., is a non-profit organization conducting agricultural, forage biotechnological, and plant biology research; providing grants to numerous non-profit charitable, educational and health organizations; and assisting farmers and ranchers through educational and consultative agricultural programs.

To learn more, check out the Noble Foundation Web site at http://www.noble.org.

More news releases available at www.noble.org/Press_Release