Is AtPLDδa target for NO-mediated S-nitrosylation?

VALIÑAS, M; DISTEFANO AM; LAMATTINA L; GARCIA-MATA C; ARJEN TEN HAVE; LAXALT AM

San Luis

Congreso; XLVII Reunión Anual de la SAIB; 2011

Previously, we demonstrated that phospholipase Dδ (AtPLDδ),one of the 12 ArabidopsisthalianaPLDs, isdownstream of nitric oxide (NO) signalling during stomatal closure. How NO activates PLDδ is still unknown. Since NO is a lipophilic compound, membrane proteins are theoretically more exposed to its chemistry. NO could directly act on proteins by nitrosylation of cysteins (S-nitrosylation). So far, there are no reports of S-nitrosylation of PLDs in either animals or plants. The aim of this study is to analyze whether AtPLDδ could be a target for S-nitrosylation. In order to determine whether any PLD from plants have the S-nitrosylation motif we did a PHI-Blast analysis. Many PLDs, including PLDδ, have the motif. In order to analyze whether AtPLDδ is S-nitrosylated, we transiently overexpress Atpldδ with c-Myc tag in tobacco leaves. We observed the presence of Atpldδ transcript by RT-PCR and measured in vitro increase PLD activity. However we could not detect the PLDδ-c-Myc protein. Interestingly, under well-water conditions these plants showed a reduced stomatal conductance respect to control ones. Under water deprivation they showed a wilting phenotype. These results support the role of AtPLDδ in water status balance. Unfortunately data about S-nitrosylation is still lacking. We are currently expressing Atpldδ in bacteria.