Abstract
Phototropins, which are members of AGCVIII kinase family, are plant specific blue-light photoreceptors having photosensory LOV domains in the N-terminus. The Arabidopsis genome contains 23 AGCVIII kinases exhibiting different expression patterns and functions. Since the kinase domains are well conserved among them, there is a possibility that AGCVIII kinases other than phototropin transduce the signal by using the pathway similar to phototropin. To investigate this possibility, we produced transgenic plants that over-expressed the kinase domains of representive AGCVIII kinases, and compared them with respect to physiological activities. In particular, we produced transgenic plants expressing the GFP-fused kinase domains of PHOT1, PHOT2, AGC1-3, KIPK, PID and OXI1 under the control of the heat-inducible promoter. The resulted plants were subjected to the physiological analysis. Consequently, distinct AGCVIII kinases interfered with the endogenous phot2 actions in the chloroplast positioning and phototropic responses. These results suggest that AGCVIII kinases have physiological acitivities similar to the PHOT2 kinase. Currently, we are analyzing stomatal opening in those plants.
