Genome-wide identification and expression analysis of C₃HC₄-type RING finger gene family in Gossypium hirsutum

The C₃HC₄-type RING finger (Ring-HC) gene family encodes zinc finger proteins crucial for plant growth and stress resistance. However, a comprehensive study on C₃HC₄-type RING finger genes in cotton has not been conducted to date. We identified 56 C₃HC₄-type RING finger genes in G. hirsutum, classified into three subfamilies with conserved structures. Evolutionary analysis indicated that this gene family has undergone strong purifying selection. Expression profiling revealed distinct tissue specificity, with significant enrichment in roots and ovules, indicating potential roles in development. Under abiotic stress, GhRHC genes showed broad responsiveness, particularly to cold. Notably, members like GhRHC1 and GhRHC34 exhibited antagonistic expression patterns: upregulation during pathogen/pest attacks but downregulation during beneficial rhizobacterial colonization. qRT-PCR analysis further confirmed the cold-induced expression of GhRHC1 and GhRHC34. Subcellular localization results preliminarily indicated that GhRHC1 and GhRHC34 proteins are localized to the nucleus and the cytoplasm. Our findings suggest that the GhRHC family plays multifaceted roles in cotton development and stress adaptation. The differential regulation of specific members suggests a possible association between differential stress-responsive regulation and the balance between defense-related responses and beneficial rhizobacterial interactions.