ibclogo XVI International Botanical Congess

Abstract Number: 5257
Session = 11.17.4


ABA SIGNAL TRANSDUCTION AND ION CHANNEL REGULATION IN ARABIDOPSIS GUARD CELLS.


J. I. Schroeder1, G. Allen1, M. Ghassemian2, P. McCourt2, C.M. Kwak1 and Z. Pei1, 1Dept. of Biology, University of California, La Jolla, CA 92093-0116, 2Botany, University of Toronto, Canada


Early steps in ABA-induced stomatal closing are mediated by ion channels and cytoplasmic signaling proteins. Farnesyltransferases can link cytosolic signaling proteins to the plasma membrane. We recently showed that deletion of the Arabidopsis farnesyltransferase ERA1 results in ABA hypersensitivity of guard cell anion channel activation and of stomatal closing (Pei et al., Science, 282: 287-290.1998). Era1 plants exhibit reduction in transpirational water loss during drought treatment. ABA induces cytosolic Ca2+ increases. New data show that the abi1 and abi2 mutants can be suppressed by activating downstream mechanisms. In addition, new data on a new mutant that modulates early ABA signaling in guard cells will be presented.

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