L-CYSTEINE DESULFHYDRASE ACTIVITY IS INVOLVED IN ABA-DEPENDENT STOMATAL CLOSURE

DENISE SCUFFI; CONSOLACIÓN ÁLVAREZ; LASPINA, NATALIA; CECILIA GOTOR; LORENZO LAMATTINA; CARLOS GARCIA-MATA

Puerto Madryn

Congreso; XLVI Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2010

SAIB

Hydrogen sulfide (H S) is a small gas that has emerged as the third 2 gasotransmitter after nitric oxide (NO) and carbon monoxide (CO). Both in animals and plants H S is synthesized by enzymes with L- 2 Cys desulfhydrase (DES) activity. In animals H S has been 2 implicated in several physiological processes. In plants, H S was 2 reported to protect plants against oxidative stress, and recently to participate in ABA-dependent stomatal closure. In the present work, we report that ABA-treated Arabidopsis wild type plants show increased levels of DES1 transcript. Interestingly, T-DNA Arabidopsis mutants des1-1 and des1-2, reported to have reduced DES activity, are impaired to close stomata in response to ABA. As expected, exogenous addition of both H S and NO donors rescued 2 des1 plants sensibility to ABA. In addition, the NO scavenger cPTIO blocks H S-dependent stomatal closure. These results 2 correlate with a H S-dependent increase of endogenous NO 2 production. Consequently, it is postulated that NO acts downstream of DES1/H S in the signaling cascade driving ABA-dependent 2 stomatal closure. Supported by UMNdP-CONICET and ANPCyT.