羽衣甘蓝白化叶控制基因AK的遗传克隆及其作用机理

Kale (Brassica oleracea var. acephala) is used as ornamental plant in autumn and winter. The albino trait is a key role for controlling the quality of the ornamental kale. In previous study, kale with albino leaves was crossed with cabbage with green leaves to construct the BC1 population and its BC1F2 populations. Segregation ratio suggested that the albino was a semi-dominant trait and controlled by a single gene. Bulked segregant analysis in combination with RNA-seq (BSR-seq) identified a single gene controlling the albino trait, named as AK (Albino Kale), which was subsequently mapped to the region between 0.75 Mb and 0.81 Mb (approximately 60 kb) on chromosome C03. An unknown function gene, CYP708A5 (Bo3g003230), which was considered as the candidate gene for AK in the target region, was preliminarily verified with transgenic experiments. In this study, the function of CYP708A5 gene will be further confirmed to investigate its variations. Furthermore, the molecular mechanism of CYP708A5 in controlling the albino leaves of kale will be dissected by transcriptome and metabolome. The present study may shed light on the genetic and metabolic pathway of albino trait in kale, which would promote future breeding of kale.

羽衣甘蓝，常作为秋冬季观赏植物，其观赏品质与白化性状紧密相关。本研究前期通过羽衣甘蓝（白化叶）和结球甘蓝（正常叶）杂交构建BC1群体和BC1F2群体，遗传分析表明白化性状为单基因控制的不完全显性遗传。BSR-seq（BSA+RNA-seq）分析鉴定到控制羽衣甘蓝白化性状的目的基因AK（Albino Kale），将其精细定位于C03号染色体上0.75Mb–0.81Mb之间约60kb的区域，并初步验证该区域最可能的候选基因CYP708A5（Bo3g003230）的功能。本研究拟在进一步验证目的基因功能的基础上，深入研究CYP708A5基因引起羽衣甘蓝白化叶形成的遗传变异；联合分析转录组和代谢组数据，解析CYP708A5控制羽衣甘蓝白化叶形成的分子机理。本研究将揭示羽衣甘蓝白化性状形成的遗传规律及其关键通路，对培育观赏性状优良的羽衣甘蓝具有重要的指导意义。

羽衣甘蓝为观赏兼食用植物，其观赏品质与白化表型紧密相关。本项目利用羽衣甘蓝（白化叶）和结球甘蓝（正常叶）杂交构建BC1群体和BC1F2群体，遗传分析表明白化性状为单基因控制的不完全显性遗传。使用BSR-seq鉴定了控制羽衣甘蓝白化性状的目的基因AK（Albino Kale），将其精细定位于C03号染色体上0.75 Mb – 0.81 Mb之间，物理位置约60 kb，并使用转基因验证了候选基因CYP708A5（Bol015404）的功能。在T1代转基因植株中，多个系均产生了白色与绿色的颜色分离，且转基因植株中AK表达水平显著高于非转基因对照。进一步使用生理学实验、转录组数据与代谢组数据鉴定羽衣甘蓝白化叶的形成与油菜素内酯（BR）的生物合成相关，推测白化叶的形成涉及BR的信号转导途径与调控。本研究揭示了羽衣甘蓝白化叶这一不完全显性性状形成的遗传规律和分子机理，对培育观赏性状优良的羽衣甘蓝具有重要的指导意义。