Genome-wide identification of WRKY transcription factors in Tetrastigma hemsleyanum (Vitaceae) highlights ThWRKY17 as a hub regulator in hormone and stress signaling

WRKY transcription factors form a major family of regulators coordinating plant development and stress adaptation. Here, we identified 69 WRKY genes from the genome of Tetrastigma hemsleyanum (Vitaceae), a traditional Chinese medicinal (TCM) plant highly sensitive to abiotic stress. Phylogenetic and structural analyses revealed a marked lineage-specific expansion of Group II and uncovered both conserved WRKY domains and novel domain combinations, indicating evolutionary diversification. Promoter analysis showed extensive enrichment of hormone- and stress-related cis-elements, particularly those responsive to abscisic acid (ABA), salicylic acid (SA), methyl jasmonate (MeJA), and light. Expression profiling under six hormone treatments highlighted ThWRKY17 as a central regulator strongly induced by ABA. Functional validation in transgenic Arabidopsis thaliana demonstrated that ThWRKY17 enhances tolerance to ABA, salt, and cold by improving germination and root growth. Yeast one-hybrid assays confirmed direct binding of ThWRKY17 to the promoters of CRPK1 , EXPA7 , and ABA8ox2 , linking ABA signaling with cold response and growth regulation. Collectively, this work provides the first genome-wide framework of the WRKY family in T. hemsleyanum , advances understanding of WRKY transcription factor evolution in Vitaceae, and identifies ThWRKY17 as a promising target for genetic improvement for stress resilience in TCM plants. ThWRKY17 integrates abiotic stress and hormone signaling, functioning as central hub to promote seed germination and seedling establishment under stress conditions. • 69 ThWRKY transcription factor genes were identified in Tetrastigma hemsleyanum (Vitaceae). • ThWRKY genes showed lineage-specific expansion within the Vitaceae. • ThWRKY17 was transcriptionally induced by ABA and involved in ABA signaling. • Overexpression of ThWRKY17 enhanced tolerance to ABA, salt, and cold stresses in Arabidopsis thaliana .