GSE186072
Jasmonic acid and dark induced leaf senescence in tomato was alleviated by knock-out of SlWRKY37
Leaf senescence can be triggered by jasmonic acid (JA) and darkness. There are scattered reports about JA and dark-induced senescence, respectively. While the precise regulatory mechanisms that integrate these two factors to initiate and regulate leaf senescence have not been identified. Here, we report a transcriptional regulating module centered on novel WRKY transcription factor that is responsible for both JA and dark-induced leaf senescence in tomato. The expression levels of SlWRKY37 together with the master transcription factor in JA signaling SlMYC2 could be significantly induced by both MeJA and dark treatments. SlMYC2 directly binds to the promoter of SlWRKY37 to active its expression. Knock out of SlWRKY37 inhibited JA and dark-induced leaf senescence. Transcriptome analysis revealed 1312 differentially expressed genes between slwrky37-CR and SlWRKY37-OE, including genes involved in JA synthesis as well as several senescence-associated genes (SAGs). We characterized SlWRKY53 and SlSGR1 as direct transcriptional targets of SlWRKY37 to regulate leaf senescence. Moreover, SlWRKY37 interacts with SlVQ7 protein in vivo and the interaction enhances its binding ability to the promoters and transcriptional activation to downstream target genes. In addition, SlWRKY37 is phosphorylated at the post-translational level. Phosphorylation of SlWRKY37 is essential for its protein interaction and transcriptional activation, indicating phosphorylation modification has a great effect on the function of SlWRKY37 protein. Our study reveals the physiological and molecular functions of SlWRKY37 in leaf senescence and offered a target gene to retard leaf yellowing by reducing the sensitivity to internal and external senescence signal such as JA and darkness. Overall design: Leaf mRNA profiles of 21-day old wild type (Micro Tom), slwrky37 and SlWRKY37-OE