Characterization of four polymorphic genes controlling red leaf colour in lettuce that have undergone disruptive selection since domestication
Characterization of four polymorphic genes controlling red leaf colour in lettuce that have undergone disruptive selection since domestication
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控制生菜红叶颜色的四个多态性基因的特征，这些生菜自驯化以来经历了破坏性选择
DOI：
10.1111/pbi.13213
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发表时间：
2019-08-08
影响因子：
13.8
通讯作者：
Chen, Jiongjiong
中科院分区：
文献类型：
--
作者：
Su, Wenqing;Tao, Rong;Chen, Jiongjiong
花青素保护植物免受生物和非生物胁迫，为消费者提供巨大的健康益处。在这项研究中，我们克隆了四个与生菜颜色变异有关的基因(红生菜叶片1至4：RLL1至RLL4)。RLL1基因编码一个bHLH转录因子，在一些品种中，5个碱基的缺失取消了它激活花青素生物合成途径的功能。RLL2基因编码一个R2R3-MYB转录因子，该转录因子是由其启动子区域的复制和突变产生的。RLL3基因编码一个R2-MYB转录因子，它通过与RLL2竞争与RLL1相互作用而下调花青素的生物合成；错义突变影响RLL3与RLL1的结合能力。RLL4基因编码一个WD-40转录因子，与抑制拟南芥UV-B信号转导途径的RUP基因同源；RLL4的错义突变减弱了其抑制功能，导致花青素的高浓度。对野生生菜和栽培生菜RLL1-RLL4基因的序列分析表明，驯化后发生了功能突变。RLL1的突变扰乱了花青素的生物合成，而RLL2、RLL3和RL4的突变激活了花青素的生物合成，表明在生菜驯化过程中对叶色的选择受到干扰。本研究中的多个多态基因的特征为合理选育红色素含量不同的生菜品种和高含量的绿色生菜品种提供了必要的分子资源。
Anthocyanins protect plants from biotic and abiotic stressors and provide great health benefits to consumers. In this study, we cloned four genes (Red Lettuce Leaves 1 to 4: RLL1 to RLL4) that contribute to colour variations in lettuce. The RLL1 gene encodes a bHLH transcription factor, and a 5-bp deletion in some cultivars abolishes its function to activate the anthocyanin biosynthesis pathway. The RLL2 gene encodes an R2R3-MYB transcription factor, which was derived from a duplication followed by mutations in its promoter region. The RLL3 gene encodes an R2-MYB transcription factor, which down-regulates anthocyanin biosynthesis through competing with RLL2 for interaction with RLL1; a mis-sense mutation compromises the capacity of RLL3 to bind RLL1. The RLL4 gene encodes a WD-40 transcription factor, homologous to the RUP genes suppressing the UV-B signal transduction pathway in Arabidopsis; a mis-sense mutation in rll4 attenuates its suppressing function, leading to a high concentration of anthocyanins. Sequence analysis of the RLL1-RLL4 genes from wild and cultivated lettuce showed that their function-changing mutations occurred after domestication. The mutations in rll1 disrupt anthocyanin biosynthesis, while the mutations in RLL2, rll3 and rll4 activate anthocyanin biosynthesis, showing disruptive selection for leaf colour during domestication of lettuce. The characterization of multiple polymorphic genes in this study provides the necessary molecular resources for the rational breeding of lettuce cultivars with distinct levels of red pigments and green cultivars with high levels of health-promoting flavonoids.