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

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

Puerto Madryn

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

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Hydrogen sulfide (H2S) is a small gas that has emerged as the third gasotransmitter after nitric oxide (NO) and carbon monoxide (CO). Both in animals and plants H2S is synthesized by enzymes with L-Cys desulfhydrase (DES) activity. In animals H2S has been implicated in several physiological processes. In plants, H2S was 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 H2S and NO donors rescued des1 plants sensibility to ABA. In addition, the NO scavenger cPTIO blocks H2S-dependent stomatal closure. These results correlate with a H2S-dependent increase of endogenous NO production. Consequently, it is postulated that NO acts downstream of DES1/H2S in the signaling cascade driving ABA-dependent stomatal closure. Supported by UNMdP-CONICET and ANPCyT.