Water Retention Gene Identified 

Description and Advantages

Scientists at the University of North Carolina at Chapel Hill, working with colleagues at Pennsylvania State University, have identified a gene responsible for controlling water retention and cell division in plants. Their discoveries, announced in two papers appearing in the journal Science, raise the possibility of making crop plants more resistant to drought. The gene the researchers worked on, known as GPA1, had already been sequenced, but its roles were unknown.

In Chapel Hill, a research team led by Alan Jones created a mutation in a gene from Arabidopsis that rendered the gene non-functional. Mutant plants wilted more readily than normal plants because they were unable to retain water as well.

The UNC scientists suspected that the gene they targeted plays a central role in regulating the various signals such as light and hormones that control plant development. But because the mutant plants wilted, they thought the gene probably also controlled water retention. This was confirmed when the scientists knocked out the gene, and found that the plants could not respond to abscisic acid as well as normal plants do. That hormone controls the opening and closing of stomatal pores.

Normally, when the soil becomes drier through lack of rainfall, guard cells increase in size to close down the openings and reduce the amount of water plants lose to the atmosphere, Jones said.  "The pores serve as conduits through which plants exchange the oxygen they produce with the carbon dioxide they use for photosynthesis," he said. "Of course, this gas exchange occurs at the cost of losing water so that plants regulate pore openings carefully via internal signals like abscisic acid."

Source:AgBiotech Reporter
Date: July 2001