A gene known to control production of proteins believed to allow plant cells to elongate during growth may also play a key role in fruit ripening, according to UC Davis plant scientists. The researchers, who identified and cloned the gene in tomatoes, suspect the gene could be useful for genetically engineering tomatoes and other perishable fruit, for which shipping quality and shelf life are critical. UC has applied to patent the gene, and the researchers reported their findings in the May 26 issue of the Proceedings of the National Academy of Sciences. The gene, LeExp1, is a member of a family of genes that coordinate production of proteins named "expansins," which loosen the plant cell walls and allow the cells to elongate during growth. "The plant cell wall is composed of a complex matrix of compounds," says Jocelyn Rose, a plant biology doctoral candidate who identified and cloned the newly discovered gene. "A major goal for many scientists in this field has been to find one gene that can be identified as being the major player in causing tissue disintegration that occurs in softening fruit," he says. Rose and colleagues think it might be possible to turn off the gene in fruits, so that they would soften later and have a longer shipping and shelf life.