Identification and validation of stem rot disease resistance genes in passion fruit

Stem rot disease is a major concern in passion fruit production, and the exploration of resistant genes is crucial for breeding varieties that are resistant to stem rot disease. In this study, we artificially inoculated Fusarium solani on the leaves of passion fruit varieties Huangjinguo and Ziguo 7. The passion fruit leaves were collected at 0h, 24h, and 48h post-inoculation for RNA-seq analysis, and 3370, 4464, and 3974 differentially expressed genes (DEGs) were identified at these stages, respectively. Gene Ontology (GO) analysis revealed that the DEGs were associated with functions such as response to reactive oxygen species (ROS), response to hydrogen peroxide, and protein complex oligomerization. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that the DEGs were mainly enriched in the phenylpropanoid biosynthesis pathway, including genes such as ZX.06G0025070, ZX.01G0064640, ZX.04G0011040, ZX.05G0011380, all of which are annotated with relevance to lignin biosynthesis. Weighted gene co-expression network analysis (WGCNA) identified three modules significantly associated with passion fruit stem rot resistance. Network analysis highlighted ZX.08G0013660 as the gene with the highest connectivity in these modules, containing a leucine-rich repeat domain. Subsequent RT-qPCR analysis confirmed that ZX.08G0013660 and others are potential candidate genes for passion fruit stem rot resistance. In conclusion, genes related to ROS and phenylpropanoid biosynthesis may play a critical role in passion fruit stem rot resistance. This study provides new insights for breeding passion fruit varieties resistant to stem rot.