Genome-Wide Identification of BPC Gene Family in Ten Cotton Species and Function Analysis of GhBPC4 Involved in Cold Stress Response

Basic Pentacysteine (BPC) represents a class of plant-exclusive transcription factors, serving pivotal roles in orchestrating developmental processes and mediating responses to both biotic and abiotic stressors. However, the genome-wide characteristics and low-temperature response mechanism of the BPC gene family in cotton remain unclear. Employing a genome-wide screening approach, this study characterized 60 distinct BPC transcription factor genes across ten Gossypium species. Conserved structural analysis showed that all BPC members carried a highly conserved GAGA-binding domain. Concurrently, the exploration of cis-acting elements within promoter regions demonstrated the potential involvement of these BPC transcription factors in modulating developmental processes, hormone signaling cascades, and abiotic stress adaptation mechanisms. Genomic collinearity analysis shows that segmental duplication is the core mechanism for the expansion of this gene family. Expression analysis indicated that the transcription level of GhBPC4 was significantly increased under low-temperature stress. Genetic function studies displayed that VIGS-mediated GhBPC4 silencing reduced cotton cold tolerance. This study systematically analyzed the genomic characteristics of the cotton BPC transcription factor family and functionally validated the molecular mechanism of GhBPC4-mediated cryogenic response. These findings establish an important foundation for subsequent analysis of multidimensional regulatory networks and the breeding of cold-resistant cotton germplasms.