IS AtPLDdelta A TARGET FOR NO-MEDIATED SNITROSYLATION?

MATIAS VALIÑAS; AYELEN M. DISTÉFANO; LAMATTINA LORENZO; CARLOS GARCÍA-MATA; TEN HAVE ARJEN; ANA M. LAXALT

San luis

Congreso; SAIB XLVII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2011

SAIB

Previously, we demonstrated that phospholipase Dd (AtPLDd), one of the 12 Arabidopsis thaliana PLDs, is downstream of nitric oxide (NO) signalling during stomatal closure. How NO activates PLDdis 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 AtPLDdcould 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 PLDd, have the motif. In order to analyze whether AtPLDdis S-nitrosylated, we transiently overexpress AtPLDdwith c-Myc tag in tobacco leaves. We observed the presence of AtPLDdtranscript by RT-PCR and measured in vitro increase PLD activity. However we could not detect the PLDd-cMyc 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 AtPLDdin water status balance. Unfortunately data about S-nitrosylation is still lacking. We are currently expressing AtPLDd in bacteria.