Hydrogen sulfide induced by hydrogen peroxide mediates darkness-induced stomatal closure in Arabidopsis thaliana
Abstract Background Whether hydrogen sulfide (H2S) mediates darkness-induced stomatal closure in A. thaliana is unknown, and the interaction between H2S and hydrogen peroxide (H2O2) in the process needs to be elucidated. Results Our results indicated that H2S modulators hypotaurine (HT), aminooxy acetic acid (AOA), hydroxylamine (NH2OH) and potassium pyruvate (N3H3KO3)+ammonia (NH3) all inhibited darkness-induced stomatal closure, H2S generation and L-/D-cysteine desulfhydras (L-/D-CDes) activity increase in wild-type A. thaliana leaves. Darkness induced stomatal closure in wild-type plants, but failed in Atl-cdes and Atd-cdes mutants. Additionally, H2S content and L-/D-CDes activity were significantly decreased after application with H2O2 modulators ascorbic acid (ASA), catalase (CAT), diphenylene iodonium (DPI), and salicylhydroxamic acid (SHAM) in darkness, but there is almost no effects on H2O2 levels when in presence of HT, AOA, NH2OH, and C3H3KO3+NH3 in darkness in wild-type plants. Moreover, darkness couldn't increase H2S content and L-/D-CDes activity of AtrbohF and AtrbohD/F mutants leaves, but the levels of H2O2 increased in guard cells of Atl-cdes and Atd-cdes mutants. Conclusions The results suggest that L-/D-CDes-generated H2S mediates darkness-induced stomatal closure, and functions downstream of H2O2 in A. thaliana.