Cirad, UMR 53 Cirad-Université de la Réunion PVBMT, Pole de Protection des Plantes, 7 chemin de l'IRAT, 97410 Saint Pierre, La Réunion, France.
Mol Phylogenet Evol. 2010 May;55(2):621-30. doi: 10.1016/j.ympev.2010.01.021. Epub 2010 Jan 28.
The phylogeny and the biogeographical history of the genus Vanilla was investigated using four chloroplastic genes (psbB, psbC; psaB and rbcL), on 47 accessions of Vanilla chosen from the ex situ CIRAD collection maintained in Reunion Island and additional sequences from GenBank. Bayesian methods provided a fairly well supported reconstruction of the phylogeny of the Vanilloideae sub-family and more particularly of the genus Vanilla. Three major phylogenetic groups in the genus Vanilla were differentiated, which is in disagreement with the actual classification in two sections (Foliosae and Aphyllae) based on morphological traits. Recent Bayesian relaxed molecular clock methods allowed to test the two main hypotheses of the phylogeography of the genus Vanilla. Early radiation of the Vanilla genus and diversification by vicariance consecutive to the break-up of Gondwana, 95 million years ago (Mya), was incompatible with the admitted age of origin of Angiosperm. Based on the Vanilloideae age recently estimated to 71 million years ago (Mya), we conclude that the genus Vanilla would have appeared approximately 34 Mya in South America, when continents were already separated. Nevertheless, whatever the two extreme scenarios tested, at least three long distance migration events are needed to explain the present distribution of Vanilla species in tropical areas. These transoceanic dispersions could have occurred via transoceanic passageway such as the Rio Grande Ridge and the involvement of floating vegetation mats and migratory birds.
采用四个叶绿体基因（psbB、psbC、psaB 和 rbcL）对 47 种香草属植物进行了系统发育和生物地理历史研究，这些植物是从留尼汪岛的 CIRAD 离体收集的香草属植物中选择的，此外还有来自 GenBank 的附加序列。贝叶斯方法为 Vanilloideae 亚科，特别是香草属的系统发育提供了相当有力的重建。在香草属中分化出三个主要的系统发育群，这与基于形态特征的实际分类（Foliosae 和 Aphyllae）不一致。最近的贝叶斯放松分子钟方法允许检验香草属的两个主要地理起源假说。香草属的早期辐射和冈瓦纳大陆分裂（9500 万年前）后的隔离分化，与被子植物的起源年龄不符。基于最近估计的 Vanilloideae 年龄为 7100 万年前，我们得出结论，香草属大约在 3400 万年前出现在南美洲，当时各大洲已经分离。然而，无论测试的两个极端情景如何，至少需要三个远距离迁移事件来解释目前热带地区香草属物种的分布情况。这些跨洋传播可能是通过里奥格兰德脊等跨洋通道，以及漂浮植被垫和候鸟的参与而发生的。
