The row data of Bulked-segregant RNA-seq (BSR) sequence of les32 and the wild-type (WT), and the row data of transcriptional sequence of zmphoh-3 and the WT B73

Other than the main source of energy for plant growth and development, carbohydrates are also known to be involved in plant defense termed sweet immunity. However, the key genetic components and molecular mechanisms underlying sweet immunity remain elusive. In this study, we identified a maize lesion mimic (les) mutant les32 that shows enhanced resistance to Curvularia leaf spot (CLS) and Southern corn rust (SCR). By map-based cloning, we found that a stop-gain mutation of ZmPHOH, encoding a cytosolic-specific starch phosphorylase, is responsible for les32-conferred les phenotype and enhanced resistance. By transcriptional analysis, we found the genes involved in phenylpropanoid biosynthesis were dominantly enriched in differentially expressed genes in the Zmphoh mutant versus the wild type. In summary, our study suggests that excessive accumulation of carbohydrates such as raffinose could trigger phenylpropanoid biosynthesis, thereby conferring multiple disease resistance (MDR) in maize. This study expands our understanding of sweet immunity and provides a direct target for genetic modifications to improve MDR in maize.