PHOTOMORPHOGENESIS REGULATION BY PROTEIN PHOSPHORYLATION

ARICO DENISE; LUCIANA CASTRO; DIEGO WENGIER; MAZZELLA AGUSTINA

Congreso; Reunión conjunta de sociedades de biociencias; 2018

Light environment provides signals for plants to develop and accomplish their life cycle successfully. Those signals are perceived and transduced by photoreceptors. Phosphorylation is one of the biochemical mechanisms initiating light signalling cascade and is a challenging question in the photobiology field today. Here, we study early light-induced phosphoproteome in Arabidopsis thaliana through a Label free LC-MS/MS proteomic approach to identify proteins which significantly change their phosphorylation status in a light-responsive way. Total proteins were extracted from three treatments: 5-d-old etiolated WT seedlings (WTD) and 5-d-old etiolated WT and phyA phyB cry1 cry2 quadruple mutant seedlings exposed for 20 min to white light pulse (100 µmol.m-2.s-1) (WTL,TETL) just before harvest. We identified 2097 phosphopeptides corresponding to 1319 proteins. 32 phosphopeptides changed significantly their phosphorylation status in response to the light treatment. 26 of them were more phosphorylated in WTL while the other 6 were less phosphorylated in WTL compared to WTD. 29 phosphopetptides changed their phosphorylation status in a photoreceptor independent manner. 3 phosphopeptides were more phosphorylated in TETL compared with WTL, suggesting that their dephosphorylation in light is mediated by the photoreceptors. Currently, we are studying the function of some of these phosphoproteins and the importance of the phosphorylation events during light signalling.