Abstract: Gaseous signal molecule hydrogen sulfide(H₂S) and plant hormone abscisic acid(ABA) modulate plant seed germination, root growth, stomatal movement, stress responses and other physiological processes, but the understanding of the relation between H₂S and ABA signaling is very limited. The transcription factors of WRKY18, WRKY40 and WRKY60 involve in ABA signaling in Arabidopsis. We used the Arabidopsis thaliana wild type(WT), lcd(L-cysteine desulfhydrase enzyme encoding gene konckdown mutant) and wrky18wrky40wrky60 mutant(WRKY18, WRKY40 and WRKY60 encoding gene knockout triple mutants) to study the interactions of H₂S, ABA and WRKY transcription factors in regulating seedling root growth and stomatal movement. The expression level of LCD and the content of endogenous H₂S in WT were increased by ABA treatment. The expression level of WRKY40 was decreased and WRKY60 was increased in WT by exogenous H₂S treatment. The expression level of WRKY18 and WRKY40 were increased, and WRKY60 was decreased in the lcd mutant. Compared with WT, the effect of ABA on seedling root growth and stomatal movement in lcd was weaker, the promoting effect of H₂S on root growth was more stronger in wrky18wrky40wrky60, but there were no obvious difference between WT and wrky18wrky40wrky60 on H₂S promoting the stomatal closure.

Key words: H₂S, ABA, WRKY transcription factors