Transcriptomic profiling of interspecific hybrid in response to Phytophthora nicotianae infection in betelvine

Betelvine (Piper betle L.) is an economically and culturally significant crop cultivated across tropical Asia, valued for its medicinal and aromatic leaves. However, its productivity is severely constrained by foot rot disease caused by Phytophthora nicotianae, a devastating oomycete pathogen that leads to wilting, root rot, and plant death. To understand the molecular mechanisms underlying disease resistance, this study investigates the transcriptomic response of an interspecific hybrid betelvine line developed through hybridization between susceptible and tolerant Piper species. Using high-throughput RNA sequencing (RNA-seq), we profiled the global gene expression patterns of infected and control plants at key time points post-infection. The comparative transcriptomic analysis aimed to identify differentially expressed genes (DEGs) involved in defense signaling, secondary metabolism, and stress adaptation. Functional annotation and pathway enrichment analyses were performed to elucidate the biological processes and molecular pathways modulated during P. nicotianae infection. Key focus areas include the activation of pathogenesis-related (PR) proteins, oxidative stress management, cell wall reinforcement, phenylpropanoid biosynthesis, and signal transduction cascades (e.g., MAPK and hormone-mediated responses). The study provides comprehensive insights into the defense architecture of the hybrid genotype, revealing potential genetic determinants of tolerance that could be exploited for breeding disease-resilient betelvine cultivars.