Expression analysis of CDPKs during Arabidopsis seedling development in dark and in response to light.

DENISE ARICO; ELISA FANTINO; RITA ULLOA; MARÍA AGUSTINA MAZZELLA

Foz de Iguazú

Congreso; 11th Congress of International Plant Molecular Biology; 2015

Plants as sessile organisms are able to sense and interpret the light environment adjusting their growth and development. In Arabidopsis thaliana red/far red light is perceived by five phytochromes (phyA to phyE). Once phytochromes are activated, they work both in the nucleus and cytoplasm through different molecular mechanisms as interaction with transcription factors and different posttranslational modifications like ubiquitination, phosphorylation. On the other side, plant CDPK proteins (calcium dependent protein kinases) coupled the changes in Ca2+ levels to specific responses through protein phosphorylation. Arabidopsis thaliana has 34 CDPKs while Solanum tuberosum has 28 CDPKs and at least StCDPK2 is induced by light. We propose to study the role of CDPKs in etiolated seedlings and in response to light. We observed that CDPK activity together with protein phosphorylation ability is increased after a far red light pulse in Arabidopsis plants, and this is absent in the phyA mutant. In microarray experiments performed in potato sprouts grown under dark/light conditions we observed that 7 StCDPK isoforms are expressed in early sprouts, suggesting that some CDPKs might have a role at the onset of growth. Our in silico studies in Arabidopsis suggest that AtCDPK1, AtCDPK5, AtCDPK9 and AtCDPK28 would be expressed in etiolated seedlings and would contain phyA binding motifs in their promoters. Real time PCR assays showed that some of these CDPKs were expressed in etiolated tissues. The analysis of activity in response to far red light of selected CDPK isoforms, their protein phosphorylation status and the behavior of cdpks mutants under far red light are currently under study. This work will give new information about CDPKs function during seedling de-etiolation. It?s supported by CONICET PIP0037, UBA and ANPCyT PICT2010 Num1821.