DISECTION OF THE FUNCTIONS OF EACH PHYTOCHROME

GUADALUPE RODRIGUEZ FERRANTE; MAXIMILIANO SANCHÉZ-LAMAS; PABLO D. CERDÁN; CHRISTIAN DAMIAN LORENZO

Rosario

Simposio; Simposio de Genomica Funcional de Plantas; 2017

IBR

To sense the changes in environmental conditions, plants had to develop different mechanisms that allow them to sense and integrate key information such as temperature and light. Arabidopsis has 13 photoreceptors capable of perceiving from UV light to Far Red. Phytochromes are a small family of five members (PHYA-E), which particularly perceive red and far red light, whose rate is affected during shading.Although the different phytochromes have overlapping roles, they have diverged in order to have agonistic and antagonistic roles at the same time, which allowed new emerging properties in the system, among other things, enhancing the photoperiodic flowering time response.Taking into account the dimeric nature of phytochromes, we decided to study the pair-wise interactions between them, using both genetic tools as genetic backgrounds that only have one or two phytochromes, as molecular tools that allow us to see interactions at the molecular level among different phytochromes or interdependent changes in the protein stability.The results obtained allowed us to see that although phyA and phyB have distinctive roles, phyC, phyD and phyE have diverged not only to improve the fine tuning of physiological responses. Regarding the induction of germination, they function as a buffer that, in one hand increases the response of phyA and phyB to the light, and in other hand antagonizes the sensitivity to Gibberellins. phyC specializes in generating an enhanced photoperiod response along with phyB, phyD in inducing germination only at prolonged irradiances, and phyE as a strong flowering repressor antagonized by phyA.