The plasma membrane ABC transporter Sl-ABCB5 mediates acylsugar secretion from tomato trichomes to confer insect resistance

Acylsugars are structurally diverse specialized metabolites secreted by glandular trichomes of Solanaceae plants and play a crucial role in defense against herbivores and pathogens. However, the mechanism underlying acylsugar secretion remains unclear. This study identifies and characterizes the plasma membrane ATP-binding cassette (ABC) transporter Sl-ABCB5 as a key component mediating acylsugar transport in trichome secretory cells of cultivated tomato (Solanum lycopersicum). Using CRISPR-Cas9-generated Sl-ABCB5 knockout mutants, we observed a dramatic reduction in trichome acylsugar accumulation, accompanied by increased susceptibility to western flower thrips (Frankliniella occidentalis). In vitro transport assays using membrane vesicles and protoplasts confirmed the ability of Sl-ABCB5 to transport acylsugars. Furthermore, virus-induced gene silencing and CRISPR-mediated knockout of ABCB5 orthologs in wild tomato (Solanumpennellii) and black nightshade (Solanum nigrum) demonstrated functional conservation of this transporter across Solanaceae species. Together, these findings reveal a conserved acylsugar transport mechanism and establish ABCB5 as a promising target for engineering enhanced insect resistance in Solanaceae crops.