PARALLEL EVOLUTION AT MULTIPLE LEVELS IN THE ORIGIN OF HUMMINGBIRD POLLINATED FLOWERS IN IPOMOEA
PARALLEL EVOLUTION AT MULTIPLE LEVELS IN THE ORIGIN OF HUMMINGBIRD POLLINATED FLOWERS IN IPOMOEA
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DOI：
10.1111/j.1558-5646.2010.00972.x
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发表时间：
2010-07-01
期刊：
影响因子：
3.3
通讯作者：
Rausher, Mark D.
中科院分区：
文献类型：
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作者：
Des Marais, David L.;Rausher, Mark D.
在被子植物中，随着传粉者行会的变化，花的颜色也发生了变化。在许多情况下，转向相似的传粉媒介与相似的花朵颜色变化有关。然而，表型水平上的这种相似性在多大程度上是由生化、发育和遗传水平上的平行变化引起的，这仍然是一个悬而未决的问题。很少有人试图确定这些较低水平的平行性是由不同类别突变的突变偏差还是固定偏差造成的。我们通过研究红色开花的牵牛花（iomoea） Mina谱系中发生的生化、发育和遗传变化来解决这些问题，并将这些变化与独立进化出红色花朵的牵牛花I. horsfalliae的变化进行比较。利用转基因技术，我们证明了Mina从蓝色到红色的花的转变主要是由于黄酮醇-3'-羟化酶（F3'H）在花中而不是在营养组织中下调，并且这种下调至少部分是由于F3'H基因的顺式调节变化。这些变化与马蹄莲所表现出的相似，表明在生化和发育水平上，甚至可能在遗传水平上具有相似性。
A transition in flower color accompanying a shift in pollinator guilds is a prominent and repeated adaptation in angiosperms. In many cases, shifts to similar pollinators are associated with similar flower-color transitions. The extent to which this parallelism at the phenotypic level results from parallel changes at the biochemical, developmental, and genetic levels, however, remains an open question. There have been few attempts to determine whether parallelism at these lower levels results from mutation bias or fixation bias of different classes of mutation. We address these issues by examining the biochemical, developmental, and genetic changes that have occurred in red-flowering species of the Mina lineage of morning glories (Ipomoea) and compare these to the changes reported for I. horsfalliae, which has independently evolved red flowers. Using transgenic techniques, we demonstrate that the transition from blue to red flowers in Mina species is due primarily to down-regulation of the enzyme flavonol-3'-hydroxylase (F3'H) in flowers but not in vegetative tissues, and that this down-regulation is at least partly due to cis-regulatory change in the gene for F3'H. These changes are similar to those exhibited by I. horsfalliae, indicating parallelism at the biochemical and developmental levels, and possibly at the genetic level.