Plant Science Department, McGill University, Sainte-Anne-de-Bellevue, QC, Canada.
Mol Plant Pathol. 2010 Nov;11(6):769-82. doi: 10.1111/j.1364-3703.2010.00643.x.
Quantitative resistance is generally controlled by several genes. More than 100 resistance quantitative trait loci (QTLs) have been identified in wheat and barley against Fusarium head blight (FHB), caused by Gibberella zeae (anamorph: Fusarium graminearum), implying the possible occurrence of several resistance mechanisms. The objective of this study was to apply metabolomics to identify the metabolites in barley that are related to resistance against FHB. Barley genotypes, Chevron and Stander, were inoculated with mock or pathogen during the anthesis stage. The disease severity was assessed as the proportion of spikelets diseased. The genotype Chevron (0.33) was found to have a higher level of quantitative resistance than Stander (0.88). Spikelet samples were harvested at 48 h post-inoculation; metabolites were extracted and analysed using an LC-ESI-LTQ-Orbitrap (Thermo Fisher, Waltham, MA, USA). The output was imported to an XCMS 1.12.1 platform, the peaks were deconvoluted and the adducts were sieved. Of the 1826 peaks retained, a t-test identified 496 metabolites with significant treatment effects. Among these, 194 were resistance-related (RR) constitutive metabolites, whose abundance was higher in resistant mock-inoculated than in susceptible mock-inoculated genotypes. Fifty metabolites were assigned putative names on the basis of accurate mass, fragmentation pattern and number of carbons in the formula. The RR metabolites mainly belonged to phenylpropanoid, flavonoid, fatty acid and terpenoid metabolic pathways. Selected RR metabolites were assayed in vitro for antifungal activity on the basis of fungal biomass production. The application of these RR metabolites as potential biomarkers for screening and the potential of mass spectrometry-based metabolomics for the identification of gene functions are discussed.
定量抗性通常由几个基因控制。在小麦和大麦中已经鉴定出 100 多个对镰刀菌穗腐病（由禾谷镰刀菌引起，无性型为赤霉）的抗性数量性状位点（QTL），这表明可能存在几种抗性机制。本研究的目的是应用代谢组学来鉴定与大麦对镰刀菌穗腐病抗性相关的代谢物。在开花期，用模拟物或病原体接种大麦基因型 Chevron 和 Stander。用受病小穗的比例来评估疾病严重程度。发现基因型 Chevron（0.33）比 Stander（0.88）具有更高水平的定量抗性。接种后 48 小时收获小穗样本；使用 LC-ESI-LTQ-Orbitrap（Thermo Fisher，Waltham，MA，USA）提取和分析代谢物。输出导入 XCMS 1.12.1 平台，对峰进行去卷积和筛选加合物。在保留的 1826 个峰中，t 检验确定了 496 个具有显著处理效应的代谢物。其中，194 个是与抗性相关的（RR）组成型代谢物，在抗性模拟接种的基因型中其丰度高于易感模拟接种的基因型。基于精确质量、碎裂模式和分子式中的碳原子数，对 50 种代谢物进行了假定命名。RR 代谢物主要属于苯丙烷、类黄酮、脂肪酸和萜烯代谢途径。根据真菌生物量的产生，在体外测定了一些 RR 代谢物的抗真菌活性。讨论了这些 RR 代谢物作为筛选潜在生物标志物的应用以及基于质谱的代谢组学在鉴定基因功能方面的潜力。
