Guard Cell Response

Science's STKE  18 Jan 2000:
Vol. 2000, Issue 15, pp. tw4
DOI: 10.1126/stke.2000.15.tw4

Of the many physiological processes that abscisic acid affects in plants, movement of guard cells is a particularly important one. By opening and closing stomata, the guard cells regulate water loss or retention through transpiration. Li et al. have now identified a component of the abscisic acid signaling cascade that is specific to guard cell action. The protein AAPK (abscisic acid-activated serine-threonine protein kinase), the gene for which has now been cloned from Vicia faba, responds through auto- and transphosphorylation to abscisic acid and is required for guard cell response to abscisic acid signals.

Li, J., Wang, X.Q., Watson, M.B., and Assmann, S.M. (2000) Regulation of abscisic acid-induced stomatal closure and anion channels by guard cell AAPK kinase. Science 287: 300-303. [Abstract] [Full Text]