The role of hydrogen sulfide and its relationship with hydrogen peroxide and nitric oxide in brassinosteroid-induced stomatal closure of Vicia faba L.

Abstract

The role of hydrogen sulfide (H2S) and its relationship with hydrogen peroxide (H2O2) and nitric oxide (NO) in brassinosteroid-induced stomatal closure by using pharmacological, spectrophotographic and fluorescence microscope approaches in Vicia faba L. were investigated. In the present study, 2, 4-epibrassinolide (EBR, a bioactive BR) induced stomatal closure in a dose- and time-dependent manner, and the effects were inhibited by H2S modulators hypotaurine (HT), aminooxy acetic acid (AOA), hydroxylamine (NH2OH), potassium pyruvate (C3H3KO3) and ammonia (NH3), H2O2 modulators ascorbic acid (ASA), catalase (CAT), diphenylene iodonium(DPI) and salicylhydroxamic acid (SHAM), and NO modulators 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO), NG-Nitro-L-arginine methyl ester, hydrochloride (L-NAME) and sodium tungstate (Na2WO4), respectively. Additionally, EBR caused increase of L-/D-cysteine desulfhydrase (L-/D-CDes) activity and H2S production in leaves, H2O2 and NO generation in guard cells, and the effects were significantly inhibited by H2S modulators, H2O2 modulators and NO modulators, respectively. Moreover, H2O2 modulators and NO modulators could significantly inhibit EBR-induced rise of L-/D-CDes activity and H2S production in the leaves of V. faba. However, H2S modulators failed to repress EBR-induced H2O2 and NO production in guard cells of V. faba. Together, our results suggested that H2S, H2O2 and NO probably participate in the signal transduction pathway of EBR-induced stomatal closure, and H2S may represent a novel component downstream of H2O2 and NO in EBR-induced stomatal closure of V. faba.