Synergistic Regulation by <i>FaTRAB1</i> and <i>FaGAPC2</i> Enhances Strawberry Resistance to <i>Tetranychus urticae</i> through Trichome Density Modulation, Lignin Accumulation, and Insect-Resistant Metabolite Biosynthesis

Trichomes are key physical and chemical barriers in plants against herbivorous insects, but their development and role in strawberry insect resistance remain unclear. This study found that overexpressing <i>FaGAPC2</i>, a glycolytic gene, increased glandular trichome density and nonglandular trichome density while raising lignin content by 26.8%. Multiomics analysis revealed that <i>FaGAPC2</i> activates phenylpropanoid biosynthesis, boosting levels of hydroferulic acid, kaempferol, and tetrandrine, reducing <i>Tetranychus urticae</i> damage by 61.5-82.8%. Y1H, LUC, and EMSA assays confirmed that bZIP transcription factor <i>FaTRAB1</i> directly activates <i>FaGAPC2</i>. <i>FaTRAB1</i> overexpression enhanced trichome density, pectin/cellulose content, and lignin accumulation by upregulating <i>FaCSE</i> and <i>FaHCT</i> while increasing the leaf thickness, forming a robust mechanical barrier. These findings demonstrate how the <i>FaTRAB1</i>-<i>FaGAPC2</i> module enhances mite resistance via trichome development, lignin deposition, and insecticidal metabolite synthesis, offering new strategies for breeding pest-resistant strawberries and developing plant-based acaricides.