Alternative splicing triggered by the insertion of a CACTA transposon attenuates LsGLK and leads to the development of pale‐green leaves in lettuce
Alternative splicing triggered by the insertion of a CACTA transposon attenuates LsGLK and leads to the development of pale‐green leaves in lettuce
复制标题
插入 CACTA 转座子引发的选择性剪接会减弱 LsGLK 并导致生菜出现淡绿色叶子
DOI：
10.1111/tpj.15563
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Jiongjiong Chen
中科院分区：
文献类型：
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作者：
Lei Zhang;Jinlong Qian;Yuting Han;Yue Jia;Hanhui Kuang;Jiongjiong Chen
莴苣（Lactuca sativa）是世界上最重要的蔬菜作物之一。莴苣作为叶菜类蔬菜，叶片从深色到浅绿绿色的多态性是其重要性状。然而，这种变化背后的遗传和分子机制仍然知之甚少。在这项研究中，使用全基因组关联研究（GWAS）确定了一个控制莴苣深色和浅绿色叶多态性的主要基因座。然后使用含有2480个后代的分离群体将该基因座精细定位到4号染色体上5375 bp的区间。在候选区域中只有一个基因与拟南芥和其他植物中的GLK基因同源。互补试验证实，候选基因LsGLK有助于深色和浅绿色叶的变异。序列分析表明，在LsGLK基因的终止密码子下游10 bp处插入了一个7434 bp的CACTA转座子，随后复制了一个1826 bp的片段，覆盖LsGLK基因的外显子3-6。转座子的插入不改变LsGLK基因的表达水平。然而，由于选择性剪接，转座子插入产生的转录物中只有6%是野生型转录物，这导致产生淡绿色叶子。进化分析表明，CACTA转座子的插入发生在栽培生菜，并可能已被选择在特定的品种，以满足消费者的不同需求。在这项研究中，我们证明了转座子插入附近的基因可能会影响其剪接，从而产生表型变异。
Lettuce (Lactuca sativa) is one of the most important vegetable crops in the world. As a leafy vegetable, the polymorphism of lettuce leaves from dark to pale green is an important trait. However, the genetic and molecular mechanisms underlying such variations remain poorly understood. In this study, one major locus controlling the polymorphism of dark‐ and pale‐green leaves in lettuce was identified using genome‐wide association studies (GWAS). This locus was then fine mapped to an interval of 5375 bp on chromosome 4 using a segregating population containing 2480 progeny. Only one gene, homologous to theGLKgenes in Arabidopsis and other plants, is present in the candidate region. A complementation test confirmed that the candidate gene,LsGLK, contributes to the variation of dark‐ and pale‐green leaves. Sequence analysis showed that a CACTA transposon of 7434 bp was inserted 10 bp downstream of the stop codon ofLsGLK, followed by a duplication of a 1826‐bp fragment covering exons 3–6 of theLsGLKgene. The transposon insertion did not change the expression level of theLsGLKgene. However, because of alternative splicing, only 6% of the transcripts produced from the transposon insertion were wild‐type transcripts, which led to the production of pale‐green leaves. An evolutionary analysis revealed that the insertion of the CACTA transposon occurred in cultivated lettuce and might have been selected in particular cultivars to satisfy the diverse demands of consumers. In this study, we demonstrated that a transposon insertion near a gene may affect its splicing and consequently generate phenotypic variations.