Genome-wide identification and characterization of the GH3 gene family in Rosa chinensis

GH3 genes encode auxin-responsive acyl acid amido synthetases and play critical roles in plant hormone homeostasis and stress responses. However, the GH3 gene family in rose (Rosa chinensis) remains poorly characterized. In this study, we performed a genome-wide identification and bioinformatic analysis of the GH3 gene family in R. chinensis, identifying eight GH3 genes (RcGH3.1–RcGH3.8). Phylogenetic analysis showed that these genes were divided into three groups, consistent with substrate specificity classification. Conserved motif analysis revealed that all proteins contained multiple conserved motifs, with RcGH3.2 lacking three motifs, suggesting functional divergence. Chromosomal localization showed that these genes were unevenly distributed on chromosomes 1, 2, 4, 5, and 6. Synteny analysis indicated that five of the eight RcGH3 genes exhibited collinear relationships with Arabidopsis GH3 genes. Promoter analysis identified various light-, hormone-, and stress-responsive cis-elements. Subcellular localization prediction showed that RcGH3.1 is nuclear-localized, while the remaining seven are cytoplasmic proteins. This study provides the first systematic characterization of the GH3 gene family in R.chinensis, laying a foundation for subsequent functional studies.