Synergistic Regulation by FaTRAB1 and FaGAPC2 Enhances Strawberry Resistance to Tetranychus urticae 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 FaGAPC2, a glycolytic gene, increased glandular trichome
density and nonglandular trichome density while raising lignin content
by 26.8%. Multiomics analysis revealed that FaGAPC2 activates phenylpropanoid biosynthesis, boosting levels of hydroferulic
acid, kaempferol, and tetrandrine, reducing Tetranychus
urticae damage by 61.5–82.8%. Y1H, LUC, and
EMSA assays confirmed that bZIP transcription factor FaTRAB1 directly activates FaGAPC2. FaTRAB1 overexpression enhanced trichome density, pectin/cellulose content,
and lignin accumulation by upregulating FaCSE and FaHCT while increasing the leaf thickness, forming a robust
mechanical barrier. These findings demonstrate how the FaTRAB1-FaGAPC2 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.