Genome-Wide Identification and Characterization of the VOZ Gene Family in Gossypium hirsutum L. and Functional Characterization in Abiotic Stress and Somatic Embryogenesis

Vascular Plant One-Zinc finger (VOZ) transcription factors are pivotal regulators of plant growth and stress adaptation, yet their functional roles in <i>Gossypium hirsutum</i>, a key fiber crop, remain poorly characterized. In this study, we systematically identified six <i>VOZ</i> genes in <i>G. hirsutum</i> and conducted a comprehensive analysis of their phylogenetic relationships, genomic distribution, promoter architecture, and expression profiles. Phylogenetic classification placed the GhVOZ proteins into three distinct clades, and chromosomal localization revealed that family expansion was likely driven by segmental duplication events. Promoter analysis uncovered an abundance of stress-related cis-regulatory elements, suggesting a potential role in abiotic stress signaling. Consistent with this, expression profiling demonstrated that <i>GhVOZ1/3</i>, <i>GhVOZ2/4/5</i>, and <i>GhVOZ6</i> were specifically induced under drought, salt, and cold stress, respectively, with qRT-PCR further confirming their tissue-specific dynamic regulation under salt treatment. Furthermore, the <i>GhVOZ</i> family exhibited stage-specific expression patterns during somatic embryogenesis. <i>GhVOZ1</i>, <i>GhVOZ3</i>, and <i>GhVOZ4</i> were upregulated at the early induction phase, implicating them in the initiation of cell reprogramming. In contrast, <i>GhVOZ2</i> and <i>GhVOZ4</i> showed sustained expression in embryogenic callus at later stages, suggesting a role in maintaining embryogenic competence, whereas <i>GhVOZ5</i>-preferentially expressed in non-embryogenic callus-may act as a repressor of embryogenesis. Synteny analysis further highlighted evolutionary conservation and subgenomic divergence of <i>VOZ</i> genes in <i>G. hirsutum</i>. Collectively, these findings establish <i>GhVOZs</i> as key regulators integrating abiotic stress response and somatic embryogenesis, providing a genetic framework for future functional studies and crop improvement.