Metabolomic Analysis of Host Plant Resistance to Thrips in Wild and Cultivated Tomatoes

Introduction - Western flower thrips (Frankliniella occidentalis) are among the most serious crop pests worldwide. Control of thrips mainly depends on pesticides, excessive use of which leads to human health risks and environmental contamination. As an alternative, we study host plant resistance to thrips. Objective - To apply nuclear magnetic resonance spectroscopy (NMR) metabolomics to study host plant resistance to thrips in wild and cultivated tomatoes. Methodology - Ten wild species and 10 cultivated tomato lines were compared. Five replicates of each species and lines were used for a thrips bioassay while another five replicates were used for the metabolornic analysis. The three most resistant and susceptible wild species, and cultivated lines, as identified by the thrips bioassay, were used for the metabolomics, performed by H-1 NMR spectroscopy followed by principal component analysis. Results - Wild and cultivated tomatoes differed significantly in thrips resistance. Only wild tomatoes were thrips-resistant, among which Lycopersicon pennellii and L. hirsutum exhibited the lowest thrips damage. Their H-1 NMR-based metabolornic profiles were significantly different from those of thrips-susceptible tomatoes. Thrips-resistant tomatoes contained acylsugars, which are known for their negative effect on herbivores. Conclusion - The identification of acylsugars as a resistance factor for thrips in tomato proves that NMR-based metabolomics an important tool to study plant defences, providing fundamental information for the development and realisation of herbivore resistance breeding programmes in agricultural crops. Copyright (C) 2009 John Wiley & Sons, Ltd.