Zinc Finger-Homeodomain Transcriptional Factors (ZHDs) in Cucumber ( L.): Identification, Evolution, Expression Profiles, and Function under Abiotic Stresses.

Cucumber ( L.) is a globally prevalent and extensively cultivated vegetable whose yield is significantly influenced by various abiotic stresses, including drought, heat, and salinity. Transcription factors, such as zinc finger-homeodomain proteins (ZHDs), a plant-specific subgroup of Homeobox, play a crucial regulatory role in stress resistance. In this study, we identified 13 distributed across all six cucumber chromosomes except chromosome 7. Phylogenetic analysis classified these genes into five clades (ZHDI-IV and MIF) with different gene structures but similar conserved motifs. Collinearity analysis revealed that members of clades ZHD III, IV, and MIF experienced amplification through segmental duplication events. Additionally, a closer evolutionary relationship was observed between the ZHDs in () and compared to (). Quantitative real-time PCR (qRT-PCR) analysis demonstrated the general expression of genes across all tissues, with notable expression in leaf and flower buds. Moreover, most of the , particularly , exhibited varying responses to drought, heat, and salt stresses. Virus-induced gene silencing (VIGS) experiments highlighted the potential functions of and , suggesting their positive regulation of stomatal movement and responsiveness to drought stress. In summary, these findings provide a valuable resource for future analysis of potential mechanisms underlying genes in response to stresses.