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 of acylsugar secretion remains unclear. This study identifies and characterizes the plasma membrane ABC transporter Sl-ABCB5 as a key component in cultivated tomato (Solanum lycopersicum) trichome secretory cell acylsugar transport. Employing CRISPR-Cas9 generated Sl-ABCB5 knockout mutants, we observed a dramatic reduction in trichome acylsugar content, accompanied by increased susceptibility to western flower thrips (Frankliniella occidentalis). In vitro transport assays using both 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 (S. pennellii) and black nightshade (S. nigrum) demonstrated functional conservation across Solanaceae species. These findings document a conserved acylsugar transport mechanism and establish ABCB5 as a target for engineering enhanced insect resistance in Solanaceae crops.