Hydrogen sulfide modulates actin-dependent auxin transport via regulating ABPs results in changing of root development in Arabidopsis.

Hydrogen sulfide (H2S) signaling has been considered a key regulator of plant developmental processes and defenses. In this study, we demonstrate that high levels of H2S inhibit auxin transport and lead to alterations in root system development. H2S inhibits auxin transport by altering the polar subcellular distribution of PIN proteins. The vesicle trafficking and distribution of the PIN proteins are an actin-dependent process. H2S changes the expression of several actin-binding proteins (ABPs) and decreases the occupancy percentage of F-actin bundles in the Arabidopsis roots. We observed the effects of H2S on F-actin in T-DNA insertion mutants of cpa, cpb and prf3, indicating that the effects of H2S on F-actin are partially removed in the mutant plants. Thus, these data imply that the ABPs act as downstream effectors of the H2S signal and thereby regulate the assembly and depolymerization of F-actin in root cells. Taken together, our data suggest that the existence of a tightly regulated intertwined signaling network between auxin, H2S and actin that controls root system development. In the proposed process, H2S plays an important role in modulating auxin transport by an actin-dependent method, which results in alterations in root development in Arabidopsis.