Indian-origin scientists in the US claim to have created a new variety of tomatoes which can stay fresh for a week longer than usual, after they found a "fountain of youth" for the delicious fruits.

A team, led by Avtar Handa of Purdue University, has in fact found that by adding a yeast gene increases production of a compound which slows ageing and delays microbial decay in tomatoes, 'The Plant Journal' reported.

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

The organic compound spermidine is a polyamine and is found in all living cells. Polyamines' functions aren't yet fully understood..

Handa and Autar Mattoo of US Department of Agriculture had shown earlier 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. We see that spermidine is important in reducing ageing. It will be interesting to discover what other roles it can have," Mattoo said.

Savithri Nambeesan, a graduate student in Handa's laboratory, introduced the yeast spermidine synthase gene, which led to increased production of spermidine in the tomatoes.