Avtar Handa, a horticulture researcher with Purdue University has succeeded in slowing the aging process of transgenic tomato plants - extending the shelf life of picked tomatoes by about a week.

Handa's lab introduced the spermidine synthase gene from yeast into the transgenic tomato plants which led to increased production of spermidine in the tomatoes. Fully ripe tomatoes from those plants lasted about eight days longer before showing signs of shriveling compared with non-transgenic plants. Decay and rot symptoms associated with fungi were delayed by about three days.

The organic compound spermidine is a polyamine and is found in all living cells. While polyamines' functions aren't yet fully understood, professor Handa and Autar Mattoo, a research plant physiologist with the U.S. Department of Agriculture's Agricultural Research Service and collaborator in the research, had previously demonstrated that polyamines such as spermidine and spermine enhance nutritional and processing quality of tomato fruits.

"At least a few hundred genes are influenced by polyamines, maybe more," Autar Mattoo said. "We see that spermidine is important in reducing aging. It will be interesting to discover what other roles it can have."

"We can inhibit the aging of plants and extend the shelf life of fruits by an additional week for tomatoes," Handa said. "This is basic fundamental knowledge that can be applied to other fruits."

Mattoo said the finding could have implications for areas that don't often get fresh fruit.

"Shelf life is a major problem for any produce in the world, especially in countries such as in Southeast Asia and Africa that cannot afford controlled-environment storage," Mattoo said.

Handa said tomato growers and possibly other fruit growers could use the finding soon if they wanted through either transgenic plants or natural breeding methods.

"We can add this gene to the tomatoes or look at natural variation and select the cultivars that already have a high level of this gene's expression," Handa said.

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