Photoreceptors modulate cold and light stress tolerance in Arabidopsis thaliana

SAEZ, JUAN PABLO; BERLI, FEDERICO; GONZALEZ, CARINA VERONICA; BOTTINI, RUBÉN; BOCCALANDRO, HERNÁN ESTEBAN

Ciudad de Mendoza

Congreso; XXVI Reunión Científica Anual Sociedad de Biología de Cuyo; 2008

Sociedad de Biología de Cuyo

Plants can detect light signals associated to open or shadowed environments using at least three photoreceptor systems: phytochromes, cryptochromes and phototopins. Coincidence of light and cold is a stressful situation, which can provoke oxidative damage in leaves, conducing to a photo-inhibition phenomenon. Our goal was to study whether perception of light signals associated to open environments by photoreceptors induce acclimation to tolerate a cold and light stressful event, at seedling and adult stages. We found that at seedling stage cryptochromes (cry1 and cry2) and phototropins (phot1 and phot2) induced acclimation to high light and low temperature. We further studied the role of these photoreceptors at adult stage. WT, phot1phot2, cry1cry2 and phytochrome (phyB) double and single null mutants were grown during 35d in a growth chamber at 20±2ºC, 16h photoperiod, under white light. Plants were exposed or not (control) to low temperatures (0-2ºC) during 11h (8h in darkness followed by 3h in light). Cold and light produced higher oxidative damage in mutants of phyB (pigment destruction, higher MDA and electrolyte leakage) and phot1phot2 (higher MDA), in spite of their higher antioxidant activity (POX).  Unexpectedly, cry1cry2 double mutant presented no oxidative damage, nor turgescency loss, as WT plants experienced when subjected to the cold and light treatment. In brief, light perception by photoreceptors is important to acclimate to stressful conditions both at seedling and adult stage.