Biochemist Daniel R. Gallie, a professor of biochemistry at the University of California, Riverside together with Zhong Chen of his research group reported their findings in the May issue of The Plant Cell.

In the study, the authors reasoned that decreasing the amount of the enzyme dehydroascorbate reductase or DHAR would reduce the ability of plants to recycle vitamin C, making them more drought tolerant through improved water conservation. The researchers accomplished this by using the plant's own gene to decrease the amount of the enzyme three fold.

Researchers used tobacco as a model for crops that are highly sensitive to drought conditions.

"However, our discovery should be applicable to most if not all crop species as the role of vitamin C is highly conserved among plants," said Gallie.

In work published last year in the Proceedings of the National Academy of Sciences, Gallie and his research team reported that the level of vitamin C could be boosted by increasing the amount of this same enzyme.

The U.S. Department of Agriculture and California Agricultural Experiment Station funded the six years of research that led to the current findings.

Vitamin C serves as an important antioxidant in plants as it does in humans and among its many functions in both, it destroys reactive oxygen species that can otherwise damage or even kill cells. "Once used, vitamin C must be regenerated otherwise it is irrevocably lost. The enzyme dehydroascorbate reductase, or DHAR, plays a critical role in this recycling process," explained Gallie.

Reactive oxygen species are produced in plants typically following exposure to environmental conditions such as drought, cold, or air pollution. Plants sense drought c
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Contact: Ricardo Duran
ricardo.duran@ucr.edu
909-787-5893
University of California - Riverside
19-Apr-2004