K+ channels inhibited by hydrogen peroxide mediate abscisic acid signaling in Vicia guard cells.
by Zhang X., Miao Y. C., An G. Y., Zhou Y., Shangguan Z. P., Gao J. F., Song C. P. (2001)
- 1College of life sciences, Northwest Sci-Tech University of Agriculture and Forestry, Yangling 712100, China.
- 2Department of Biology, Henan University, Kaifeng 475001, China.
- 3National Laboratory of Soil Erosion and Dryland Farming, the Institute of Soil and Water Conservation, Chinese Academy of Sciences, Yangling 712100, China.
in Cell Research 11, 195–202. –
A number of studies show that environmental stress conditions increase abscisic acid (ABA) and hydrogen peroxide (H2O2) levels in plant cells. Despite this central role of ABA in altering stomatal aperture by regulating guard cell ion transport, little is known concerning the relationship between ABA and H2O2 in signal transduction leading to stomatal movement.
Epidermal strip bioassay illustrated that ABA-inhibited stomatal opening and ABA-induced stomatal closure were abolished partly by externally added catalase (CAT) or diphenylene iodonium (DPI), which are a H2O2 scavenger and a NADPH oxidase inhibitor respectively.
In contrast, internally added CAT or DPI nearly completely or partly reversed ABA-induced closure in half-stoma.
Consistent with these results, whole-cell patch-clamp analysis showed that intracellular application of CAT or DPI partly abolished ABA-inhibited inward K+ current across the plasma membrane of guard cells.
H2O2 mimicked ABA to inhibit inward K+current, an effect which was reversed by the addition of ascorbic acid (Vc) in patch clamping micropipettes.
These results suggested that H2O2mediated ABA-induced stomatal movement by targeting inward K+channels at plasma membrane.