Plant Science Department, McGill University, Sainte-Anne-de-Bellevue, QC, H9X 3V9, Canada.
J Chem Ecol. 2011 Aug;37(8):846-56. doi: 10.1007/s10886-011-9989-1. Epub 2011 Jun 24.
Resistance in Triticeae to fusarium head blight (FHB) is quantitatively inherited. Metabolomics as a tool was used to better understand the mechanisms of resistance and to identify potential FHB resistance biomarker metabolites in barley. Five FHB-resistant two-row barley genotypes (CIho 4196, Zhedar-1, Zhedar-2, Fredrickson, and Harbin-2r) and one FHB-susceptible genotype (CH 9520-30) were each inoculated with either pathogen-suspension or mock-solution. Disease severity, quantified as the proportion of spikelets diseased, varied among genotypes, being the greatest in CH 9520-30. Spikelets were sampled, metabolites extracted with aqueous methanol, and analyzed using an LC-ESI-LTQ-Orbitrap system. A pair wise, resistant vs. susceptible, t-test identified 1774 significant treatment peaks. Canonical discriminant analysis of peak abundance allowed the genotypes to be sorted into three clusters: (i) CH9520-30, (ii) Harbin-2r, (iii) the remaining four genotypes. The t-test was further used to identify resistance-related (RR) and pathogenesis-related (PR) metabolites. The pathogen-produced virulence factor deoxynivalenol (DON), and its detoxification product, DON-3-O-glucoside (D3G) were designated as resistance indicator (RI) metabolites. Metabolites (RR, PR, or RI) occurring in at least two resistant genotypes, showing a two-fold or greater abundance in resistant vs. susceptible lines, and also known to have plant defense functions were selected as potential FHB resistance biomarker metabolites. These included phenylalanine, p-coumaric acid, jasmonate, linolenic acid, total DON produced (TDP), and the proportion of DON converted to D3G (PDC). Total DON was the lowest in CIho 4196, while PDC was the highest in Zhedar-2. The application of RR, PR, and RI metabolites as potential biomarkers to enhance resistance is discussed.
小麦赤霉病（FHB）抗性是定量遗传的。代谢组学作为一种工具，用于更好地理解抗性机制，并鉴定大麦中潜在的 FHB 抗性生物标志物代谢物。五个 FHB 抗性二棱大麦基因型（CIho 4196、Zhedar-1、Zhedar-2、Fredrickson 和 Harbin-2r）和一个 FHB 敏感基因型（CH 9520-30）分别用病原菌悬浮液或模拟溶液接种。用病原菌悬浮液接种后，用模拟溶液接种的病情严重程度（用病穗率表示）在基因型间存在差异，CH 9520-30 的病情最严重。采集穗部样本，用含水甲醇提取代谢物，并用 LC-ESI-LTQ-Orbitrap 系统进行分析。两两比较，抗性与敏感，t 检验鉴定出 1774 个显著的处理峰。对峰丰度进行的典型判别分析允许将基因型分为三个簇：（i）CH9520-30，（ii）Harbin-2r，（iii）其余四个基因型。t 检验进一步用于鉴定与抗性相关（RR）和与发病机制相关（PR）的代谢物。病原菌产生的毒性因子脱氧雪腐镰刀菌烯醇（DON）及其解毒产物 DON-3-O-葡萄糖苷（D3G）被指定为抗性指示（RI）代谢物。至少在两个抗性基因型中存在的代谢物（RR、PR 或 RI），在抗性与敏感品系之间的丰度增加两倍或更多，并且已知具有植物防御功能，被选为潜在的 FHB 抗性生物标志物代谢物。这些包括苯丙氨酸、对香豆酸、茉莉酸、亚油酸、总 DON 产量（TDP）和 DON 转化为 D3G 的比例（PDC）。CIho 4196 中的总 DON 最低，而 Zhedar-2 中的 PDC 最高。讨论了将 RR、PR 和 RI 代谢物作为潜在生物标志物应用于增强抗性。
