ITHACA, N.Y. -- The fruits of genetic research are about to ripen: Scientists at the U.S. Department of Agriculture (USDA) and the Boyce Thompson Institute for Plant Research, Inc. (BTI), located on the campus of Cornell University, have discovered a gene that controls ripening in tomatoes.
This means that tastier, more-nutritious grocery-store tomatoes are not far behind, say the researchers in an article in the latest issue of the journal Science (April 12, 2002), titled "A MADS-box gene necessary for fruit ripening at the tomato ripening-inhibitor (rin ) locus."
"For understanding tomato ripening and eventually taste, this could be the Holy Grail," says Jim Giovannoni, a project scientist with the USDA and also with BTI.
MADS refers to a family of genes (the name is an acronym formed from the initials of the four original members of the family). More than 100 MADS-box sequences have been found in species of microbes, animals and plants, and most play important roles in developmental processes. Most prominent, the MADS-box genes in owering plants are the "molecular architects" of growth.
Giovannoni and his colleagues have found two tandem MADS-box genes, one a ripening gene, the LeMADS-RIN (or rin for short), and the other the LeMADS-MC gene, which controls the development of the sepal -- the collar of pointy green leaves at the top of tomatoes. Finding these genes provides the first molecular insight into a non-hormonal way to ripen fruit, he says.
The shelf life of tomatoes was lengthened by the discovery in the early 1960s, by Henry Munger, Cornell professor of plant breeding, of a mutant tomato plant containing what Giovannoni and his group now have shown to be a defect in the rin gene. Munger crossed this mutant plant with normal tomatoes, allowing the fruit to reach full size while slowing the ripening process. Today, this hybrid is commercially ubiquitous. But, says Giovannoni, in order to be
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