Scientists at the University of California, Riverside, studying plant tolerance of low oxygen stress (a condition that can be caused by flooding or poor soil irrigation and that can result in significant crop losses), report in the June 14th, 2002, issue of the journal Science that plants use a rheostat-like mechanism at the cellular level to balance the production of an enzyme (i.e., a kind of protein) with the consumption of stored carbohydrates. The enzyme, called "ADH" (alcohol dehydrogenase), is needed for plant survival when little oxygen is available. The research is likely to interest biotechnologists and has vast implications, particularly for agriculture.
"Plants vary in their ability to tolerate low oxygen conditions," said Julia Bailey-Serres, associate professor of genetics at UC Riverside and a coauthor of the paper. "In our study we focused on the thale cress weed and detected a molecular switch in many of the root cells. This switch, called 'Rop,' needs to be turned up and then down to initiate the proper physiological response to this stress of low oxygen."
"This is breakthrough research," said Airica Baxter-Burrell, graduate student in plant genetics at UC Riverside and lead author of the paper. "We have new information on the low-oxygen pathway in plant cells, affecting the way we study these cells. It is likely that the molecular switch we found in the thale cress weed is present in most plants. But is the switch working the same way in all of them? We are looking into that now. We feel confident that the same switching mechanism operates in at least rice and corn."
Bailey-Serres, whose laboratory has been studying the response of plants to flooding for 12 years, explained that in a flooding situation oxygen is limited; so the production of energy gets limited, too. In other words, a cellular energy crisis kicks in. When this happens, an organism can still produce a limited amount of energy through "glycolys
Contact: Iqbal Pittalwala
University of California - Riverside