Stem nematode disease resistance-conferring gene identification in sweet potato using combined BSA-Seq and BSR-Seq analyses.

Stem nematode disease, the most prevalent of three major diseases in northern China, causes huge sweet potato production losses. In this study, the resistant (Zhenghong22) and sensitive (Longshu9) parents, and the F segregating population mixed pools (Resistant- and Sensitive-Mixed) having extreme resistance traits, were used for BSA-Seq, BSR-Seq, and transcriptomic analyses to locate stem nematode disease resistance-conferring genes in sweet potato. Transcriptome results indicated that ethylene and ABA were the main hormones involved in disease resistance regulation, with secondary metabolic pathways playing crucial roles. In total, 7 and 17 candidate regions, which contained 743 candidate genes, were identified in the BSA-Seq and BSR-Seq analyses, respectively. Eight candidate genes were identified using a combined analysis. The protein phosphatase 2C gene itf15g20460, the signal transduction-related gene itf00g76200, and an unknown functional gene itf00g75950, were identified as key resistance gene candidates through RT-qPCR validation in mixed pools and individuals. These results will be beneficial to the cultivation of nematode-resistant sweet potato cultivars.