Researchers at the Salk Institute for Biological Studies studying the frumpy wild mustard plant Arabidopsis thaliana rather than the elegant rose recently determined why plants with a defective TOPLESS gene form an extra root where the shoot should be. Their findings, published in the June 9th issue of the journal Science, suggest that it is possible to engineer a plant cell to develop in ways that better suit agricultural needs.
"If we know how a plant forms a root instead of a shoot, and that there is time in which to make such an important change, it might be possible to tell a plant to make a leaf instead of a flower," says the study's lead author, Jeffrey A. Long, Ph.D., an assistant professor in the Plant Molecular and Cellular Biology Laboratory. "We can now think about plant development in a different way."
The study, which included researchers from the laboratory of Elliot M. Meyerowitz, Ph.D., at the California Institute of Technology, specifically focused on understanding mutations in the TOPLESS gene that Long had previously identified in Arabidopsis thaliana, the first flowering plant to have its genome sequenced and a popular model organism for many aspects of plant biology.
Like animals, plants develop along a polar axis, but with a root on one end and a shoot on the other. A defective TOPLESS gene, however, causes plant embryos to develop into a seedling with two oppositely oriented root poles ?hence the gene's name. Long asked how mutations in TOPLESS can switch a plant cell's fate from shoot to root, hoping to discover how cells at the "basal" end of plant embryos become roots, while cells at the top or "apical" end become shoots that give rise to leaves, bra