Broad-spectrum arthropod resistance in hybrids between high- and low-acylsugar tomato lines

Abstract

Three elite tomato (Solanum lycopersicum L., syn. Lycopersicon esculentum Mill.) breeding lines (TOM-687, TOM-688, TOM-689) with high foliar acylsugar (AS) contents were obtained, and used along with two low-AS lines (TOM-690, TOM-684) in hybrid combinations, to obtain six hybrids between one low-AS line × one high-AS line (= hybrids with intermediate AS levels), one hybrid between two high-AS lines (= high-AS hybrid), and one hybrid between two low-AS lines (= low-AS hybrid). These genotypes were tested for resistance to three different tomato pests (spider mites [Tetranychus urticae Koch], silverleaf whitefly [Bemisia argentifolii Bellows & Perring], and the South American tomato pinworm [Tuta absoluta (Meyrick)]) along with hybrid TEX-154 (low-AS) and/or Solanum pennellii Correll ‘LA-716’ (high-AS wild accession). In all three instances, high-AS genotypes showed higher levels of pest resistance than low-AS genotypes. Hybrids with intermediate AS levels showed resistances that were just as high as those of high-AS genotypes for Bemisia argentifolii and Tuta absoluta, and nearly as good as those for Tetranychus urticae. Acylsugars were confirmed as being a major component of the high levels of pest resistances found in S. pennellii—a component that was successfully introgressed into elite tomato breeding lines. Acylsugar-mediated pest resistance is effective against a broad spectrum of tomato pests. Because high-AS breeding lines are scarce, the deployment of hybrids between high-AS line × low-AS line would be a quick, viable alternative to obtain commercial pest-resistant hybrids.