Abstract
Plant development is responsive to environmental cues, and many of the regulatory proteins that mediate these responses are only found in plants. In Arabidopsis, GIGANTEA (GI) plays key roles in the control of circadian rhythms, flowering determination and light signaling through phytochrome signaling. We show here that Drought induced 19 (Di19), a zinc-finger protein, interacts with GI in vitro and in planta. Di19 protein localizes to the nucleus. di19 mutation suppresses late flowering of phyA mutants and enhances the elongation of hypocotyl under red light conditions when combined with mutations in genes encoding related zinc-finger proteins genes. The loss of function of Di19 affected the period of circadian rhythms in GIGANTEA expression. Together with these data, we propose the importance of interaction between GI and Di19 in phytochrome-mediated regulation of the control of circadian rhythm, light signaling and flowering in Arabidopsis.
