Abstract
Chloroplast avoidance movement is mediated by phototropin 2 (phot2). The velocity of the avoidance movement in PHOT2/phot2-1 heterozygote is slower than that in WT. Because the PHOT2 amount in the heterozygote is less than that in WT, it is supposed that the velocity of the avoidance is dependent upon the PHOT2 amount. Thus, we investigated whether the phot2-dependent responses were controlled by the PHOT2 amount.
PHOT2-GFP (P2G) was introduced into phot1phot2 double mutants of Arabidopsis. We isolated transgenic plants that showed 0 to 20 fold accumulation of PHOT2 than that in WT and examined phot2-related responses. While the velocity of the chloroplast avoidance movement was dependent on the P2G amount, almost leaves of the transgenic plants grew to flat despite the P2G amount under natural light condition. These results suggested that threshold levels of the PHOT2 amount were dependent upon light induced physiological responses.
