Transcriptome analysis reveals resistance induced by Benzothiadiazole against soft rot in Chinese cabbage

Soft rot caused by Pectobacterium carotovorum (Pc) is a harmful disease in Brassica rapa, resulting in severe yield loss. Benzothiadiazole (BTH) can improve plant resistance to various pathogens by inducing systemic acquired resistance (SAR) pathway. In this study, susceptible wild type (WT) and resistant mutant sr in Chinese cab-bage-both treated with BTH showed high resistance to Pc infection. Transcriptome analysis showed a series of differentially expressed genes (DEGs) involved in the regulation of leucine-rich repeat resistance (LRR) proteins, peroxidase (POD) accumulation, transcription regulatory factors, and other defense response functions. In particular, WRKY75 and PR4 genes were significantly induced by pathogens and BTH in WT and sr. BTH trig-gered the increase of endogenous SA. In addition, the enhanced activities of phenylalanine ammonia lyase (PAL) and POD promoted the accumulation of lignin after BTH treatment. We inferred that the lignin played significant roles in BTH-induced resistance of Chinese cabbage resistance to Pc. We present the potential molecular mechanism of BTH-induced resistance for soft rot resistance in Chinese cabbage, which provides a basis for further study of the resistance mechanism of Chinese cabbage to soft rot.