Regulation of stomatal closure by COP1 in Arabidopsis

Abstract

In higher plants, stomata are paths for gas exchange. Therefore, stomata are important for the growth of plants (Weyers and Meidner, 1990). It is known that stomata of wild type plants are closed in darkness while stomata of cop1 mutants are open. Furthermore, stomata apertures of cop1 mutants are wider than those of wild type plants under various light conditions (Mao et al., 2005 CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1) is ubiquitin E3 ligase. COP1 is located nucleus in darkness and degrades proteins for photomorphogenesis (Lau and Deng, 2012). To know if COP1 controls not only darkness-related stomata closure but also stress-related stomata closure, we investigated the effect of various stress conditions on stomata closure of wild type plants and cop1 mutants. Furthermore, we tried to investigate how COP1 controls stomata closure. All of these data demonstrate that stomata of cop1 mutants are not closed under heat stress or ABA treatment while these of wild type plants are not. However, under various stress or not, there is not special difference in RNA expressional levels. Stomata closure-related proteins which interact with COP1 are not identified through Yeast two-hybrid assay. These results indicate that COP1 controls stress-related stomata closure and subsequent studies are needed to investigate the mechanism.