Hydrogen peroxide is involved in hydrogen sulfide-induced lateral root formation in tomato seedlings

BACKGROUND: Both hydrogen sulfide (H(2)S) and hydrogen peroxide (H(2)O(2)) are separately regarded as a highly reactive molecule involved in root morphogenesis. In this report, corresponding causal link governing lateral root formation was investigated. METHODS: By using pharmacological, anatomic, and molecular approaches, evidence presented here revealed the molecular mechanism underlying tomato lateral root development triggered by H(2)S. RESULTS: A H(2)S donor sodium hydrosulfide (NaHS) triggered the accumulation of H(2)O(2), the up-regulation of RBOH1 transcript, and thereafter tomato lateral root formation. Above responses were sensitive to the H(2)O(2) scavenger (dimethylthiourea; DMTU) and the inhibitor of NADPH oxidase (diphenylene idonium; DPI), showing that the accumulations of H(2)O(2) and increased RBOH1 transcript were respectively prevented. Lateral root primordial and lateral root formation were also impaired. Further molecular evidence revealed that H(2)S-modulated gene expression of cell cycle regulatory genes, including up-regulation of SlCYCA2;1, SlCYCA3;1, and SlCDKA1, and the down-regulation of SlKRP2, were prevented by the co-treatment with DMTU or DPI. Above mentioned inducing phenotypes were consistent with the changes of lateral root formation-related microRNA transcripts: up-regulation of miR390a and miR160, and with the opposite tendencies of their target genes (encoding auxin response factors). Contrasting tendencies were observed when DMTU or DPI was added together. The occurrence of H(2)S-mediated S-sulfhydration during above responses was preliminarily discovered. CONCLUSIONS: Overall, these results suggested an important role of RBOH1-mediated H(2)O(2) in H(2)S-elicited tomato lateral root development, and corresponding H(2)S-target proteins regulated at transcriptional and post-translational levels. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12870-017-1110-7) contains supplementary material, which is available to authorized users.