Abstract

Radish (Raphanus sativus L.) belongs to the family Brassicaceae. The Yunnan red radish variety contains relatively large amounts of anthocyanins, making them important raw materials for producing edible red pigment. However, the genetic mechanism underlying this pigmentation has not been fully characterized. Here, the radish inbred line YAAS-WR1 (white root skin and white root flesh) was crossed with the inbred line YAAS-RR1 (red root skin and red root flesh) to produce F₁, F₂, BC₁P₁, and BC₁P₂ populations. Genetic analyses revealed that the pigmented/non-pigmented and purple/red traits were controlled by two genetic loci. The F₂ population and the specific-locus amplified fragment sequencing (SLAF-seq) technique were used to construct a high-density genetic map (1230.16 cM), which contained 4032 markers distributed in nine linkage groups, with a mean distance between markers of 0.31 cM. Additionally, two quantitative trait loci (QAC1 and QAC2) considerably affecting radish pigmentation were detected. A bioinformatics analysis of the QAC1 region identified 58 predicted protein-coding genes. Of these, RsF3′H, which is related to anthocyanin biosynthesis, was revealed as a likely candidate gene responsible for the purple/red trait. The results were further verified by analyzing gene structure and expression. Regarding QAC2, RsMYB1.3 was determined to be a likely candidate gene important for the pigmented/non-pigmented trait, with a 4-bp insertion in the first exon that introduced a premature termination codon in the YAAS-WR1 sequence. Assays demonstrated that RsMYB1.3 interacted with RsTT8 and activated RsTT8 and RsUFGT expression. These findings may help clarify the complex regulatory mechanism underlying radish anthocyanin synthesis. Furthermore, this study’s results may be relevant for the molecular breeding of radish to improve the anthocyanin content and appearance of the taproots.

中文翻译：

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基于特异性位点扩增片段测序的高密度遗传图谱构建及云南红萝卜花色苷色素控制位点鉴定

 抽象的

萝卜（ Raphanus sativus L.）属于十字花科。云南红萝卜品种含有较多的花青素，是生产食用红色素的重要原料。然而，这种色素沉着的遗传机制尚未完全阐明。这里，萝卜自交系YAAS-WR1（白色根皮和白色根肉）与自交系YAAS-RR1（红色根皮和红色根肉）杂交产生F ₁ 、F ₂ 、BC ₁ P ₁和BC ₁ P ₂群体。遗传分析表明，色素/非色素和紫色/红色性状由两个基因位点控制。利用F ₂群体和特异性位点扩增片段测序（SLAF-seq）技术构建高密度遗传图谱（1230.16 cM），其中包含分布在9个连锁群中的4032个标记，标记之间的平均距离为0.31 厘米。此外，还检测到两个显着影响萝卜色素沉着的数量性状基因座（QAC1和QAC2）。对 QAC1 区域的生物信息学分析确定了 58 个预测的蛋白质编码基因。其中，与花青素生物合成相关的RsF3′H被认为是负责紫色/红色性状的可能候选基因。通过分析基因结构和表达，进一步验证了结果。关于 QAC2， RsMYB1.3被确定为对色素/非色素性状很重要的可能候选基因，在第一个外显子中插入 4 bp，在 YAAS-WR1 序列中引入提前终止密码子。分析表明，RsMYB1。3与RsTT8相互作用并激活RsTT8和RsUFGT表达。这些发现可能有助于阐明萝卜花青素合成的复杂调节机制。此外，这项研究的结果可能与萝卜的分子育种有关，以提高花青素含量和主根的外观。