May 26, 1999

Plant Genome Project Leader Joins The Salk Institute

Salk News


Plant Genome Project Leader Joins The Salk Institute

La Jolla, CA – Joseph R. Ecker, one of the nation’s leading authorities on the molecular biology and genetics of plants, will be joining the faculty of The Salk Institute, effective next summer.

Among other things, Ecker is a principal investigator in a multinational effort to sequence the genome of Arabidopsis thaliana, a modest weed that’s become a model organism for the study of plant genetics.

“Joe is one of the top modern plant biologists in the world,” said Joanne Chory, professor and chair of Salk’s plant biology program.

“The local plant science community is excited to see him come here. Bringing Joe Ecker to San Diego shows the strength of this community.”

Added Ecker: “I am thrilled about joining this world-class research institute and the growing community of outstanding plant biologists in San Diego.”

Ecker comes to Salk from the Plant Science Institute at the University of Pennsylvania (Penn) where he was a professor of biology. While at Penn, he became widely regarded as one of the foremost experts on how the gaseous hormone ethylene regulates a variety of basic plant processes. For agriculture, ethylene gas is a vital chemical messenger important for such processes as fruit ripening and how plants respond to pathogenic organisms.

In his laboratory, Ecker has been trying to unravel the precise molecular pathway that governs how ethylene gas works in plants. To accomplish this task, Ecker and his colleagues have been inducing changes, or mutations, in the genetic code of Arabidopsis to help identify the gene’s function.

In many respects, plant biologists now study Arabidopsis the way animal geneticists study fruit flies. A member of the mustard plant family, this commonplace weed has one socially redeeming quality – it has the smallest complement of genetic material known in any plant, making it easy to manipulate and engineer. The plant also grows fast – from seed to seed in six weeks.

Although Ecker successfully identified several ethylene-signaling genes in the 1980s, the process was slow and painstaking. After a decade of work, he and his research team identified only about a quarter of the genes in the ethylene pathway.

“It became clear that this approach would be totally inadequate to fully understand how ethylene ‘works’ before my retirement in approximately 25 to 30 years,” said Ecker.

To speed the process, scientists are now turning to the plant genome project, a parallel to the human genome project that is attempting to map the 100,000 genes that make up the human organism. Unlocking the secrets of Arabidopsis’ genome will provide the raw material to test the ideas about plant function at the molecular level.

The project, jointly funded by the National Science Foundation and the U.S. Departments of Energy and Agriculture, is spearheaded by three consortia in this country including one led by Ecker and researchers at Stanford and UC Berkeley. It’s expected that the entire genome will be solved within a year.

“Only then will we discover all the genes necessary to ‘grow’ a plant and by inference, all the genes necessary for ethylene response,” said Ecker. “The first results of plant genome science will be a better understanding of the processes by which fruits and vegetables ripen, and from that, methods to prevent spoilage.”

After receiving his bachelor’s degree in 1978 from The College of New Jersey, based in Trenton, N.J., Ecker enrolled at Pennsylvania State University where he was awarded a Ph.D. in microbiology in 1982. He then moved to Stanford University, where he completed his postdoctoral studies in biochemistry under Ronald W. Davis. Following his formal education, in 1987 Ecker joined the faculty of the University of Pennsylvania and the Plant Science Institute.

He is a member of the Genetics Society of America, the American Society of Microbiology, the American Society of Plant Physiologists and the International Society for Plant-Microbe Interactions.

The Salk Institute for Biological Studies, located in La Jolla, Calif., is an independent nonprofit institution dedicated to fundamental discoveries in the life sciences, the improvement of human health and conditions, and the training of future generations of researchers. The Institute was founded in 1960 by Jonas Salk, M.D., with a gift of land from the City of San Diego and the financial support of the March of Dimes Birth Defects Foundation.

But the targets for LEAFY remained at large until the current study.

“It stood to reason that LEAFY would activate the so-called ABC genes, patterning genes that were known to be turned on in different structures of the flower,” said Busch. “And now we have the first direct evidence that LEAFY attaches to these genes and switches them on.”

The patterning genes “instruct” different parts of a flower to develop into sepals, petals, stamens or carpels. The “A” genes are active in the outer parts of the flower, the sepals and petals; the “C” genes specify the inner sections, the reproductive structures; and the “B” genes overlap.

The current study shows that LEAFY activates a gene called AGAMOUS, a member of the “C” family, and investigators expect that other ABC genes will also have switches controlled by LEAFY. Having all the signals in hand should allow for the engineering of flowers with particular desired features.

“For example,” said Weigel, “we know that plants missing the AGAMOUS gene don’t make any reproductive organs. Instead the A genes take over the whole flower, producing many extra petals, a spectacular effect that horticulturists find appealing. Knowing all the cues that lend a flower its size and shape should permit the deliberate design of flowers through genetic manipulations. For example, the selective removal of stamens would eliminate pollen, a common allergen.”

Thus, bringing to the garden prettier posies and sneeze-free sniffs.

Co-first author Kirsten Bomblies is a research assistant in Weigel’s laboratory. The study, titled “Activation of a floral homeotic gene in Arabidopsis,” was supported by the National Science Foundation and the Department of Energy. Busch was the recipient of a fellowship from the Human Frontier Science Program Organization.

The Salk Institute for Biological Studies, located in La Jolla, Calif., is an independent nonprofit institution dedicated to fundamental discoveries in the life sciences, the improvement of human health and conditions, and the training of future generations of researchers. The Institute was founded in 1960 by Jonas Salk, M.D., with a gift of land from the City of San Diego and the financial support of the March of Dimes Birth Defects Foundation.

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