Abstract
The Mitogen-Activated Protein Kinase (MAPK) family plays a crucial role in environmental signal transduction and stress adaptation in plants. However, the MAPK gene family in Gossypium hirsutum remains incompletely characterized, limiting its utilization for improving stress resilience. In this study, we identified 56 GhMPKs in cotton and systematically analyzed their genomic organization, phylogenetic relationships, and expression patterns under drought, salinity, and heat stress. Phylogenetic classification grouped GhMPKs into four distinct categories (A-D). Tissue-specific expression profiling revealed that GhMPK10 was ubiquitously expressed across developmental stages, suggesting its broad regulatory roles. Under abiotic stresses, GhMPK10 displayed sustained induction, implicating its central role in stress signaling. Functional validation through Arabidopsis overexpression and virus-induced gene silencing in cotton confirmed GhMPK10 as a critical regulator of drought and salt tolerance. Transcriptomic analysis of silenced plants highlighted disrupted MAPK signaling pathways, including downregulation of ABA-responsive stomatal closure genes (PYR/PYL, ABF) and ethylene biosynthesis regulators (GhACS1). Protein interaction networks further implicated GhMPK10 in key stress-responsive kinase pathways (GhMAPKK8/9/10) and transcription factors (GhSPCH), which regulate stomatal patterning. This study is the first to identify GhMPK10 as a key regulator of abiotic stress tolerance through phosphorylation signaling, providing valuable molecular targets for breeding stress-resilient cotton varieties.