番茄中开展的基于代谢物的关联研究

      代谢组学是指对广泛的代谢产物进行全面高通量定量分析的一种研究方式，其在人类、动物和植物表型及诊断研究中具有重要的价值。GWAS是用来检测全基因组范围内的常见遗传变异与可观测性状之间遗传关联的一种方法。现在，科研领域已开始利用GWAS揭示代谢物组天然变异的遗传和分子基础。最近，法国农业科学院和先正达公司的研发人员为了改良番茄的风味品质，利用代谢组和GWAS联合分析，揭示了控制酸味和挥发物含量的基因组区域。

      番茄原产南美洲，中国南北方广泛栽培，是重要的果蔬。有研究显示，现代番茄口味欠佳的主要原因是在选育过程中，糖、酸、香味挥发物等几种重要口味相关化学成分的缺失。研究人员分析了300个番茄种质资源（包括野生种）的代谢谱，并对60个初级和次级代谢产物（包括挥发性物质）进行了定量分析。同时，他们分析了1万个SNP标记，鉴定了与代谢产物的关联性，其中有4个基因组区域与代谢物的多态性有关，2个野生番茄中的基因与挥发物苯丙素、果实酸含量这些影响番茄风味品质的初级和次级代谢物相关。
      这个在番茄中开展的基于代谢物的关联研究证实了这种方法在代谢途径基因鉴定、代谢途径分析、性状遗传改良中的应用价值。

 New Phytol. 2017 Jun 6.
Identification of major loci and genomic regions controlling acid and volatile content in tomato fruit: implications for flavor improvement.
Author
Bauchet G, Grenier S, Samson N……Baxter C, Grivet L, Causse M.
INRA, UR1052, GAFL, 67 Allée des Chênes Domaine Saint Maurice - CS60094; Syngenta, 12 Chemin de lHobit, France.
Abstract
Plant metabolites are important to world food security due to their roles in crop yield and nutritional quality. Here we report the metabolic profile of 300 tomato accessions (Solanum lycopersicum and related wild species) by quantifying 60 primary and secondary metabolites, including volatile organic compounds, over a period of 2 yr. Metabolite content and genetic inheritance of metabolites varied broadly, both within and between different genetic groups. Using genotype information gained from 10 000 single nucleotide polymorphism markers, we performed a metabolite genome-wide association mapping (GWAS) study. We identified 79 associations influencing 13 primary and 19 secondary metabolites with large effects at high resolution. Four genome regions were detected, highlighting clusters of associations controlling the variation of several metabolites. Local linkage disequilibrium analysis and allele mining identified possible candidate genes which may modulate the content of metabolites that are of significant importance for human diet and fruit consumption. We precisely characterized two associations involved in fruit acidity and phenylpropanoid volatile production. Taken together, this study reveals complex and distinct metabolite regulation in tomato subspecies and demonstrates that GWAS is a powerful tool for gene-metabolite annotation and identification, pathways elucidation, and further crop improvement.