Novel interactions between light and temperature signaling

MAXIMILIANO SANCHEZ-LAMAS; CERDAN, PABLO DIEGO

Congreso; 16th International Congress on Photobiology; 2014

International Union of Photobiology

Novel interactions between light and temperature signaling Sánchez Lamas, Maximiliano a, Cerdán Pablo D.b a Leloir Foundation Institute, E-mail: msanchez@leloir.org.ar b Leloir Foundation Institute, E-mail: pcerdan@leloir.org.ar Light signals are essential for plant growth and development. For this reason, plants have at least 4 families of photoreceptors that allow them to sense both the quantity and quality of light. The UV-B light is percibed by UVR8, whereas blue and UV-A light is sensed by three families of photoreceptors cryptochromes (CRY1-2), phothotropins (PHOT1-2) and the single LOV domain photoreceptors (ZTL, FKF, LKP2). Finally, red and far-red light is perceived by phythochromes (PHYA-E) {Kami, 2010 #1}. The ability to withstand environmental temperature variation is essential for plant survival. Previous reports have shown that shade avoidance responses that are sensed by the phythochromes induce similar phenotypes to high temperature responses (paper de Halliday mas nuevo 2010 o 2011). Hence, we decided to characterize the temperature dependence of the phyB mutant phenotype during deetiolation. We used physiological measures (hypocotyl length), transcriptomic (microarrays), qRT-PCR and genetic approaches. The results shown that at non stressing ranges, plants are permanently sensing the temperature, showing mostly linear responses to both duration and temperature range. Further, phyB and other photoreceptors play key roles in buffering this response, with different relative weights at different temperatures. We found that auxins play an important rol by several reasons: the gene expression analysis showed higher levels of auxin responsive genes only when the interaction light-temperature was evident; the ectopically added auxins were able to suppress these interactions; and because this genotype-temperature is highly dependent on the presence of auxin synthesis genes. With respect to the mechanism, we found a cytochrome P450 which showed an important temperature by genotype interaction in its expression pattern. We propose that this cytochrome might be necessary to regulate hypocoyl growth at lower temperatures under shade conditions, by an auxin dependent mechanism.