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 <i>Taxus</i>-an ancient gymnosperm valued for paclitaxel production. This study aimed to identify the <i>Taxus SnRK</i> family and elucidate its functional roles. Specifically, we identified <i>SnRK</i> 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 <i>SnRK</i> genes (2 <i>SnRK1</i>, 4 <i>SnRK2</i>, 13 <i>SnRK3</i>) were identified, with tissue-specific expression revealing <i>TaSnRK1.2</i> upregulation under methyl jasmonate (MeJA) and in stress-resilient tissues (bark/root). Subsequently, WGCNA uncovered a bark/root-specific module containing <i>TaSnRK1.2</i> with predicted TF interactions (<i>TaGRAS</i>/<i>TaERF</i>). Critically, homologous dual-luciferase assays demonstrated <i>TaSnRK1.2</i> activates <i>TaGRAS</i> and <i>TaERF</i> promoters (4.34-fold and 3.11-fold induction, respectively). This study establishes the <i>Taxus SnRK</i> family and identifies <i>TaSnRK1.2</i> 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.