Systematic analysis of cotton beta galactosidases and their expression profiles under abiotic stresses and gibberellin treatment

In plants, the beta galactosidases (BGALs) function in various biological processes, including growth, development and responses to abiotic stresses. However, the evolutionary patterns and stress-regulatory roles of the BGAL gene family across multiple Gossypium species remain largely unclear. In this study, a total of 58, 38, 25, and 26 BGAL genes were identified in Gossypium barbadense , Gossypium hirsutum , Gossypium herbaceum and Gossypium raimondii , respectively. Together with Arabidopsis BGALs, the newly identified cotton BGAL members were classified into eight groups, and their chromosome distribution was mapped. Genome-wide gene duplication analysis indicated that segmental duplication played a crucial role in the expansion and evolution of the BGAL gene family. Expression profiling revealed that GhBGAL genes were expressed in multiple tissues and exhibited distinct responses to cold, heat, salt, and drought stresses, suggesting their important roles in abiotic stress adaptation. Promoter analysis and qRT-PCR further showed that most GhBGAL genes contained gibberellin (GA)-responsive cis -elements and their expression responded rapidly responded to GA treatment, suggesting that BGALs may coordinate with GA signaling to regulate cotton development. Our results systematically reveal the evolutionary and functional characteristics of cotton BGALs, and provide key candidate genes for dissecting stress tolerance mechanisms and facilitating the genetic improvement of cotton.