Molecular analysis of the anthocyanin2 gene of petunia and its role in the evolution of flower color
Molecular analysis of the anthocyanin2 gene of petunia and its role in the evolution of flower color
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DOI：
10.1105/tpc.11.8.1433
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发表时间：
1999-08-01
期刊：
影响因子：
11.6
通讯作者：
Koes, R
中科院分区：
文献类型：
--
作者：
Quattrocchio, F;Wing, J;Koes, R
花的形状和颜色对植物繁殖很重要，因为它们吸引昆虫和鸟类等传粉者。因此，人们认为这些性状的改变可能导致不同传粉者的吸引、遗传隔离，最终导致(共处)物种形成。矮牵牛和腋下矮牵牛开出不同形状和颜色的花，似乎有不同的昆虫造访。花青素2(An2)基因是花青素生物合成途径的调节者，是颜色差异的主要决定因素。在这里，我们报告了在矮牵牛进化过程中发生在AN2基因座上的分子事件的分析。我们用转座子标签技术分离了an2，发现它编码一个MYB结构域的蛋白，表明它是一个转录因子。对白花腋生黄粉菌亚种的分析表明，它们含有一个2(-)等位基因，在一个位置有两个交替的移码，显然是由转座子的插入和随后的切除引起的。第三个AN2(-)等位基因在其他地方有一个无义突变，表明它是独立产生的。AN2(-)等位基因的多态分布表明，AN2功能的丧失和随之而来的花色变化不是整叶黄杨和腋下黄杨遗传分离的主要原因。相反，它们是在物种形成过程的后期发生的事件，可能是为了加强遗传隔离和完整的物种形成。
The shape and color of flowers are important for plant reproduction because they attract pollinators such as insects and birds. Therefore, it is thought that alterations in these traits may result in the attraction of different pollinators, genetic isolation, and ultimately, (sympatric) speciation. Petunia integrifolia and P axillaris bear flowers with different shapes and colors that appear to be visited by different insects. The anthocyanin2 (an2) locus, a regulator of the anthocyanin biosynthetic pathway, is the main determinant of color differences. Here, we report an analysis of molecular events at the an2 locus that occur during Petunia spp evolution. We isolated an2 by transposon tagging and found that it encodes a MYB domain protein, indicating that it is a transcription factor. Analysis of P axillaris subspecies with white flowers showed that they contain an2(-) alleles with two alternative frameshifts at one site, apparently caused by the insertion and subsequent excision of a transposon. A third an2(-) allele has a nonsense mutation elsewhere, indicating that it arose independently. The distribution of polymorphisms in an2(-) alleles suggests that the loss of an2 function and the consequent changes in floral color were not the primary cause for genetic separation of P. integrifolia and P. axillaris. Rather, they were events that occurred late in the speciation process, possibly to reinforce genetic isolation and complete speciation.