CONTROL OF BRASSINOSTEROID SIGNALING BYSHADE AND TEMPERATURE CUES

CECILIA COSTIGLIOLO ROJAS; SANTIAGO MORA GARCIA; JORGE CASAL

Cordoba

Congreso; LII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2016

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Plants respond to the shade imposed by neighbors by modifying their growth patterns to produce a more competitivebody form. Shade reduces the activity of photosensoryreceptors phytochromes and cryptochromes and henceincreases the activity of PHYTOCHROME-INTERACTING FACTORS (PIFs), which are bHLH transcription factors that regulate the expression of growth-related genes. Warm temperature also increases PIF activity and yield growthpatterns that resemble shade responses.Brassinosteroids are potent promoters of growth, and mutants affecting this pathway barely respond to shade signals.BRASSINAZOLE-RESISTANT1 (BZR1) and BRI1-EMS-SUPPRESSOR1 (BES1) are positive regulators of the BRsignaling pathway that physically interact with PIFs and synergistically regulate the expression of growth-promoting genes. We investigated whether shade and/or temperature cues affect brassinosteroid signaling. We will report the dynamics of BES1protein levels and phosphorylation status and of BES1 nuclearabundance in hypocotyls and cotyledons of plants expressing pBES1:BES1:GFP. Current results support a model where shade and temperature signals modify the activity of BES1.