Function of BBX proteins in plant light signaling.

BOTTO JF

Rosario

Congreso; L Reunión Nacional de la SAIB; 2014

Sociedad Argentina de Investigacion en Bioquimica y Biologia Molecular

Plants have evolved sophisticated photosensory systems to respond and convert the light information into biological signals. After germination, etiolated seedlings perceive light and promote de-etiolation that includes hypocotyl inhibition and development of photosynthetic cotyledons. After seedling establishment, plants grow and become mutually shaded. To increase the chances to compete for light, sun plants are capable to induce the shade avoidance syndrome, a group of physiological responses being the most prominent the elongation of stem and petioles. These developmental processes promote a massive transcriptional reprogramming finely modulated by the activity of transcription factors.  Here in this talk, I will describe the functional characterization of a group of zinc-finger transcription factors that contain a tandem repeated B-boxes (BBX) involved in seedling de-etiolation and shade avoidance response. In particular, I will demonstrate the action of BBX24 and BBX25 in both processes. They are negative regulators of photomorphogenesis and act additively in the control of de-etiolation through the inhibition of HY5 activity. Furthermore, BBX24 and BBX25 promote additively cell elongation under shade light. This talk will present some evidence of BBX protein functions in the shade signaling pathway.