U.S.: Cornell researchers discover plant leaf 'fountain of youth'
Scientists from Cornell University in New York have found what they call the fountain of youth for plant leaves. Led by Cornell horticulture professor Su-Sheng Gan, the team considers the finding key to elongating freshness.
Studying small flowering plant Arabidopsis thaliana, the researchers discovered the gene S3H, a regulator that when found at high levels holds off senescence or plant wilting.
"It was serendipity – we weren’t actually looking for this gene, but it turned up in an earlier survey of genes involved in leaf senesce," Gan said.
"When we characterized it, we found more than we were looking for: a key step in the plant’s pathway for controlling senescence that had been eluding scientists."
The gene interacts with salicylic acid, a hormone that drives development and aids response to pathogenic attacks. S3H breaks down salicylic acid and slows down the death process.
Normal plants with the gene were found to take more than nine days to turn from green to yellow. Without the gene, plants took only three days.
"What we have found is the convergence point between the slow and fast death systems," Gan said.
"When the plant starts to accumulate salicylic acid, it turns on S3H, which then acts as a brake on the process by breaking down the salicylic acid, giving the plant enough time to recycle all the reusable parts."
In the future, Gan hopes manipulation of the gene could elongate plant life by weeks. This could mean leafy greens that stay fresh longer and fruits that maintain their nutrients on the shelf.
"Much of the progress plant breeders have made in improving plant yields is actually due to delaying leaf senescence," Gan said.
"You need long-lived green tissue to support the production of fruits, vegetables and seeds, so senescence limits the yield of many crops."
Photo: Gan examining seedlings, by Cornell University