LncRNA33732‐respiratory burst oxidase module associated with WRKY1 in tomato‐ Phytophthora infestans interactions

Summary Our previous studies indicated that tomato WRKY 1 transcription factor acts as a positive regulator during tomato resistance to Phytophthora infestans . However, the molecular mechanism of WRKY 1‐mediated resistance regulation remains unclear. Here, we used a comparative transcriptome analysis between wild‐type and WRKY 1 ‐overexpressing tomato plants to identify differentially expressed genes ( DEG s) and long non‐coding RNAs ( DEL s), and we examined long non‐coding RNA (lnc RNA )‐gene networks. The promoter sequences of the upregulated DEG s and DEL s were analyzed. Among 1073 DEG s and 199 DEL s, 1 kb 5′‐upstream regions of 59 DEG s and 22 DEL s contain the W‐box, the target sequence of the WRKY 1. The results of promoter−β ‐ glucuronidase ( GUS) fusion and yeast one‐hybrid assay showed that lnc RNA 33732 was activated by WRKY 1 through sequence‐specific interactions with the W‐box element in its promoter. The overexpression and silencing analysis of lnc RNA 33732 in tomato showed that lnc RNA 33732 acts as a positive regulator and enhanced tomato resistance to P. infestans by induction of the expression of respiratory burst oxidase ( RBOH ) and increase in the accumulation of H 2 O 2 . When the expression of RBOH gene was inhibited in tomato plants, H 2 O 2 accumulation decreased and resistance were impaired. These findings suggest that lnc RNA 33732 activated by WRKY 1 induces RBOH expression to increase H 2 O 2 accumulation in early defense reaction of tomato to P. infestans attack. Our results provide insights into the WRKY 1−lnc RNA 33732− RBOH module involved in the regulation of H 2 O 2 accumulation and resistance to P. infestans , as well as provide candidates to enhance broad‐spectrum resistance to pathogens in tomato.