Deciphering the genetic basis of plant secondary metabolism will provide useful insights for genetic improvement and enhance our fundamental understanding of plant biological processes. Although citrus plants are among the most important fruit crops worldwide, the genetic basis of secondary metabolism in these plants is largely unknown. Here, we use a high-density linkage map to dissect large-scale flavonoid metabolic traits measured in different tissues (young leaf, old leaf, mature pericarp, and mature pulp) of an F1 pseudo-testcross citrus population. We detected 80 flavonoids in this population and identified 138 quantitative trait loci (QTLs) for 57 flavonoids in these four tissues. Based on transcriptional profiling and functional annotation, twenty-one candidate genes were identified, and one gene encoding flavanone 3-hydroxylase (F3H) was functionally verified to result in naturally occurring variation in dihydrokaempferol content through genetic variations in its promoter and coding regions. The abundant data resources collected for diverse citrus germplasms here lay the foundation for complete characterization of the citrus flavonoid biosynthetic pathway and will thereby promote efficient utilization of metabolites in citrus quality improvement.

中文翻译：

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使用 Citrus reticulata × Poncirus trifoliata 种群基于多组学的柑橘类黄酮代谢解剖

破译植物次生代谢的遗传基础将为遗传改良提供有用的见解，并增强我们对植物生物过程的基本理解。尽管柑橘类植物是世界上最重要的水果作物之一，但这些植物中次生代谢的遗传基础在很大程度上是未知的。在这里，我们使用高密度连锁图来剖析在 F 的不同组织（幼叶、老叶、成熟果皮和成熟果肉）中测量的大规模黄酮代谢特征。1伪测交柑橘种群。我们在该人群中检测到 80 种黄酮类化合物，并确定了这四种组织中 57 种黄酮类化合物的 138 个数量性状基因座 (QTL)。基于转录谱和功能注释，鉴定出 21 个候选基因，以及 1 个编码黄烷酮 3-羟化酶的基因。F3H)经功能验证，通过其启动子和编码区的遗传变异导致二氢山柰酚含量自然发生变化。此处收集的丰富的柑橘种质资源数据资源为完整表征柑橘类黄酮生物合成途径奠定了基础，从而促进代谢物在柑橘品质改善中的有效利用。