Hydrogen sulfide induces hydrogen peroxide and nitric oxide mediation of salt stress-caused stomatal closure in Arabidopsis thaliana (L.) Heynh

The roles of H2S, hydrogen peroxide (H2O2) and nitric oxide (NO) in signaling transduction of stomatal movement response to salt stress in Arabidopsis thaliana (L.) Heynh. are still unknown. The role of H2S and its relationship with H2O2 and NO in salt stress-caused stomatal closure by using pharmacological, spectrophotographic and fluorescence microscopic approaches in A. thaliana were investigated. Our results will provide evidence for further elucidating the signal transduction mechanism of stomatal movement caused salt stress in plants. Salt stress caused stomatal closure in wild-type and AtrbohD mutant, these effects were prohibited by H2S modulators, H2O2 modulators, NO modulators in wild-type, respectively. However, salt stress couldn't significantly change the stomatal aperture of Atl-cdes, Atd-cdes, Atnoa1, nia1-2, nia2-1, nia1-2/nia2-5, AtrbohF and AtrbohD/F mutants. Salt stress caused rise of H2S content and L-/D-cysteine desulfhydrase (L-/D-CDes) activity of leaves in wild-type and AtrbohD mutant, but these effects were prevented by H2S modulators in wild-type. H2O2 modulators and NO modulators significantly inhibited salt stress-caused H2O2 production and NO synthesis in wild-type, respectively. These results suggested that H2S, H2O2 and NO participate in salt stress-caused stomatal closure. H2O2 modulators and NO modulators prevented salt stress-caused H2S synthesis and L-/D-CDes activity increase in leaves of wild-type, but H2S modulators couldn't inhibit salt stress-caused H2O2 production and NO synthesis in wild-type. Salt stress increased H2O2 and NO levels in Atl-cdes and Atd-cdes mutants, but failed to cause H2S synthesis and L-/D-CDes activity increase in AtrbohF, AtrbohD/F, Atnoa1, nia12, nia2-1 and nia1-2/nia2-5 mutants. All the data suggested that salt stress induced H2O2 and NO production, subsequent caused H2S synthesis, and finally closed stomata in A. thaliana.