Genome-Wide Characterization of the SnRK Gene Family in Taxus and Homologous Validation of TaSnRK1.2 as a Central Regulator in Stress-Responsive Transcriptional Networks

SnRK kinases, central regulators of plant stress response, remain uncharacterized in Taxus—an ancient gymnosperm valued for paclitaxel production. This study aimed to identify the Taxus SnRK family and elucidate its functional roles. Specifically, we identified SnRK genes through genomic analysis and assessed tissue-specific expression via transcriptomics, while regulatory networks were deciphered using WGCNA. To overcome experimental constraints, a PEG-mediated protoplast transient expression system was developed using calli, followed by dual-luciferase assays. Consequently, 19 SnRK genes (2 SnRK1, 4 SnRK2, 13 SnRK3) were identified, with tissue-specific expression revealing TaSnRK1.2 upregulation under methyl jasmonate (MeJA) and in stress-resilient tissues (bark/root). Subsequently, WGCNA uncovered a bark/root-specific module containing TaSnRK1.2 with predicted TF interactions (TaGRAS/TaERF). Critically, homologous dual-luciferase assays demonstrated TaSnRK1.2 activates TaGRAS and TaERF promoters (4.34-fold and 3.11-fold induction, respectively). This study establishes the Taxus SnRK family and identifies TaSnRK1.2 as a hub integrating stress signals (e.g., MeJA) to modulate downstream TF networks, while the novel protoplast system enables future functional studies in this medicinal plant.