一个影响酪氨酸代谢藜麦突变体的鉴定

Characterization of a Quinoa Mutant Affecting Tyrosine Metabolism

【目的】利用收集的藜麦植株颜色突变体,测定该突变体的代谢组成,分析代谢通路之间变化和转化规律,构建出该突变体代谢变化基本模型,为进一步鉴定和克隆影响藜麦重要代谢通路的关键遗传位点提供材料基础。【方法】利用正向遗传学手段,从藜麦常规品种‘藜红1号’(Red Quinoa 1,RQ1)后代中,筛选到一植株和穗部红色消退而绿色加深(green quinoa 1,gq1)的自然突变株作为材料,与其原始亲本RQ1相比较,利用非靶向代谢组学鉴定灌浆时期幼穗差异代谢成分,通过KEGG(Kyoto encyclopedia of genes and genomes)代谢途径分析和差异代谢物关联分析,揭示GQ1基因突变引发的关键代谢通路的变化。【结果】经过连续4个世代的遗传分析表明,gq1突变体植株颜色变异能够稳定遗传,且是由单个遗传位点控制。与其原始亲本RQ1相对比,在藜麦gq1突变体中检测到了409个差异代谢物,其中含量升高的代谢物有110个,299个代谢物含量降低。代谢组学分析发现,在藜麦gq1突变体中,对植物次级代谢有着重要影响的酪氨酸和以其为核心衍生出的其他代谢产物发生了整体性的降低。此外,包括6种人体必需氨基酸在内的多种氨基酸和TCA循环中的成分,在gq1突变体发生了显著的减少。【结论】通过对这些差异代谢进行KEGG代谢途径富集分析,表明GQ1基因突变造成了以酪氨酸为核心的初级代谢组分和次级代谢组分整体降低,意味着该基因可以成为协同优化藜麦初级代谢和次级代谢的关键遗传位点。

【Objective】Quinoa,known as the“golden grain”for its rich beneficial secondary metabolites and nutritional components for human benefit,is explored in this study through the analysis of a color mutant isolated from quinoa natural population.By examining the metabolic composition of this mutant,analyzing the changes and transformation routes between metabolic pathways,and constructing a basic model of metabolic changes in the mutant,this study is aimed to provide a material basis for further identification and cloning of key genetic loci affecting important metabolic pathways in quinoa.【Method】Using forward genetics,a natural mutant exhibiting reduced red pigmentation and intensified green coloration(green quinoa 1,gq1)was screened from the progeny of the quinoa cultivar,‘Red Quinoa 1’(RQ1).This mutant was compared with its original parent,RQ1,to identify differential metabolic components in the young panicle of grain filling stage using untargeted metabolomics.KEGG metabolic pathway analysis and correlation analysis of differential metabolites were employed to reveal the overall differences in metabolic pathways and some key nutritional components in the mutant gq1.【Result】Genetic analysis conducted over four successive generations indicates that the color variation in the gq1 mutant quinoa plants was stably inherited and was controlled by a single genetic locus.Compared to its original parent RQ1,409 differential metabolites were detected in the quinoa gq1 mutant,with the concentration of 110 metabolites increased and that of 299 metabolites decreased.Metabolomics analysis revealed a comprehensive decrease in tyrosine and its derivative metabolites in the quinoa gq1 mutant,which are crucial for plant secondary metabolism.Moreover,a significant reduction was observed in various amino acids,including six essential amino acids for humans,and components of the TCA cycle in the gq1 mutant.【Conclusion】The enrichment analysis of these differential metabolites through KEGG metabolic pathways indicates that the gq1 gene mutation leads to a general reduction in both primary and secondary metabolic components centered around tyrosine.This suggests that the gene could serve as a key genetic locus for the synergistic optimization of primary and secondary metabolism in quinoa.