Genome-Wide Analysis of GLK Gene Family in Four Cotton Species Provides Insights into Their Involvement in Cotton Abiotic Stress Response

Cotton is a crucial economic crop that supplies natural fibers for the textile industry, with fiber quality being greatly impacted by abiotic stress throughout its growth stages. The Golden2-Like ( GLK ) gene family plays a key role in plant development and adaptation to abiotic stress. However, the specific functions and regulatory mechanisms of GLK members in cotton remain largely unexplored. In this study, a thorough analysis of GLK in four cotton species ( Gossypium arboreum , G. raimondii , G. hirsutum , and G. barbadense ) was conducted. A total of 198 GLK genes were identified in cotton. Conserved sequence analysis revealed that most GLK proteins contain two highly conserved domains: a MYB DNA-binding domain and a C-terminal (GCT) box. Promoter element analysis results show that the GLK gene family contains many stress response-related elements. Expression analysis demonstrated that GhGLK2 , GhGLK11 , GhGLK16 , and GhGLK30 responded significantly to drought, salt, and temperature stresses. And GhGLK2 , GhGLK13 , GhGLK38 , GhGLK42 , and GhGLK46 responded significantly to cotton development. Yeast one-hybrid, yeast two-hybrid, and dual-luciferase assay results indicate that GhGLK2 interacts with GhGUN5 , GhPIL6 , GhNAC6 , GhTPX2 , and GhERF10 . These findings suggest that these GhGLKs may play crucial roles in regulating the response to abiotic stress. Overall, this study provides a solid theoretical foundation for understanding the role of the GLK gene family in cotton’s response to abiotic stress.