A transcription factor SlWRKY71 activated the H2S generating enzyme SlDCD1 enhancing the response to Pseudomonas syringae pv DC3000 in tomato leaves

Abstract

• H₂S is a well-known gaseous signaling molecule that plays important roles in plant response to biotic stresses. Pseudomonas syringae pv tomato (Pst) could cause enormous loss, while whether H₂S could modulate plant defense against Pst is still unclear.
• By CRISPR/Cas9, the Sldcd1 gene editing mutant showed reduced endogenous H₂S content and attenuated resistance, whereas treatment with exogenous H₂S could enhance the resistance. A transcription factor, SlWRKY71, was screened and identified to promote the transcription of SlDCD1 via yeast one-hybrid, dual-luciferase reporter system, electrophoretic mobility shift assays, and transient overexpression.
• Here, it was found that exogenous H₂S relieved the symptoms of bacterial speck disease in tomato leaves, conferring tolerance to Pst. DC3000, and the expression of the H₂S-producing enzyme SlDCD1 was significantly induced. The Slwrky71 mutant also showed reduced defense in tomato leaves against Pst. DC3000, whereas SlWRKY71-OE tomato leaves showed increased tolerance. Transient overexpression of SlDCD1 in the context of Slwrky71 with exogenous H₂S treatment has stronger resistance, and the overexpression of SlWRKY71 in the context of Sldcd1 showed relatively weak disease resistance, and with the addition of H₂S enhanced the effect.
• Therefore, we concluded that SlWRKY71 could activate SlDCD1 expression and promote endogenous H₂S production, thereby improving tomato leaves resistance to Pst. DC3000.