Genome-wide characterization and expression profiling of the gene family in sweet orange () reveal responses to multiple phytohormones and abiotic stresses.

Citrus is widely recognized as one of the most economically important fruit crops worldwide. However, citrus growth is frequently hindered by external environmental stresses, which severely limit its development and yield. The TGA (TGACG motif-binding factor) transcription factors (TFs) are members of the bZIP family and play essential roles in plant defense responses and organ development. Nevertheless, the systematic identification and functional analysis of the TGA family in citrus remains unreported. In this study, genome-wide analysis identified a total of seven CsTGA TFs in , which were classified into five subgroups. Phylogenetic and syntenic analysis revealed that the genes are highly conserved, with no tandem or segmental duplication events among family members. Promoter sequence analysis identified numerous -acting elements associated with transcriptional regulation, phytohormone response, and environmental adaptation in the promoters of genes. The expression patterns under five phytohormones and three abiotic stresses demonstrated significant responses of multiple genes under various forms of adversity. Among all tested treatments, showed the most robust response to multiple stresses. Tissue-specific expression pattern analysis revealed potential functional biases among genes. In-depth analysis showed that CsTGA7 localized in the nucleus and possessed transcriptional activation activity, consistent with the typical characteristic of transcriptional regulators. In summary, our research systematically investigated the genomic signature of the TGA family in . and unearthed with potential functions in phytohormone signaling transduction and abiotic stress responses. Our study establishes a basis for further exploration of the function of genes under abiotic stress.