Genome‐Wide Identification and Expression Analysis of Pathogenesis‐Related Protein 1 in Sweet Potato and Its Two Relatives

ABSTRACT Pathogenesis‐related Protein 1 (PR1) is a core component of plant innate immunity and plays crucial roles in plant growth, development, and stress response, especially biological stress. However, limited information is available on the PR1 genes in sweet potato and other Ipomoea species. In this study, 33, 50, and 36 PR1 or PR1‐like genes were identified from sweet potato ( I. batatas ), I. trifida, and I. triloba , respectively. Phylogenetic analysis categorized these genes into five groups, reflecting their evolutionary divergence. Cis‐regulatory elements associated with light, hormone, and stress responses. Tissue‐specific expression profiling of I. trifida and I. triloba revealed high expression levels in the flowers and flower‐buds, indicating potential roles in reproductive developmental processes. Stress response analysis showed that most PR1 genes in sweet potato were downregulated under biotic and abiotic treatments, whereas IbPR1‐5 was consistently upregulated across all three stress conditions. Our study provides novel insights into the evolutionary dynamics of PR1 genes across the three Ipomoea genomes and contributes to the future molecular breeding of sweet potato cultivars.