EXPRESSION ANALYSIS OF CDPKS DURING ARABIDOPSIS SEEDLING DEVELOPMENT IN DARK AND IN RESPONSE TO LIGHT

ARICO DENISE; FANTINO ELISA; ULLOA RITA; MAZZELLA, MARIA AGUSTINA

Foz de Iguazu

Congreso; IPMB 2015; 2015

IPMB, comité binacional Argentina-Brasil

Plants are able to sense and interpret 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 phosphorylation. On the other side, plant?s 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. CDPK activity together with protein phosphorylation ability are increased after a far-red light pulse in Arabidopsis, and this is absent in the phyA mutant. Microarray experiments performed in potato sprouts grown under dark/light conditions revealed that 7 StCDPK isoforms are expressed in early sprouts, suggesting that some CDPKs might have a role at the onset of growth. 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. RT-qPCR assays showed that some of these CDPKs were expressed in etiolated tissues. The 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.