SlBTA2 is required for cuticle biosynthesis in tomato fruit

Fruit cuticle, as a specialized hydrophobic cell wall architecture covering the surface of fruit, is crucial for fruit resistance to biotic and abiotic stress. In this study, we found that the BTB protein, SlBTA2, can regulate the biosynthesis of fruit cuticle in tomato. SlBTA2 was mainly expressed in the epidermis of fruits. Knockout of SlBTA2 inhibits the formation of fruit cuticle, resulting in a reduced cuticle thickness, accelerated post-harvest water loss, uneven colouring and increased cell wall thickness. GC-MS quantification revealed drastic reductions of cutin (94%) and wax (34%) monomer content in slbta2 fruits, especially 9(10),16-dihydroxyhexadecanoic acid (>90%). Moreover, transcriptome profiling identified coordinated downregulation of key cuticle biosynthesis genes in mutant fruits, such as SlANL2b, SlLACS2, SlCER1-2, etc. Overall, our findings present that SlBTA2 is a novel breeding target for cuticle accumulation and post-harvest fruit qualities.