Molecular phylogeny and habitat diversification of the genus Farfugium (Asteraceae) based on nuclear rDNA and plastid DNA.
Molecular phylogeny and habitat diversification of the genus Farfugium (Asteraceae) based on nuclear rDNA and plastid DNA.
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DOI：
10.1093/aob/mcq139
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发表时间：
2010-09
期刊：
影响因子：
4.2
通讯作者：
Naofumi Nomura;T. Takaso;C. Peng;Yoshiko Kono;K. Oginuma;Y. Mitsui;H. Setoguchi
中科院分区：
文献类型：
--
作者：
Naofumi Nomura;T. Takaso;C. Peng;Yoshiko Kono;K. Oginuma;Y. Mitsui;H. Setoguchi
背景与目的野菊花属（Farfugium）是菊科（Asteraceae）的一个小属，包括野菊花属（F. japonicum和F.分布于东亚沿着一个漫长的群岛上。常见的分类群为F. japonicum，包括三个品种与广泛的栖息地，包括森林下层（sciophytes），沿海悬崖（日光植物）和河床（rheophytes）。叶的形状是本属内一个重要的分类特征，并与生境有关。方法收集20个居群，包括所有的Farfugiumtaxis在其整个范围内。叶形态进行了测量，以确定分类群之间的差异。分别对核rDNA内转录间隔区（internal transcribed spacer）和4个质体DNA区域（matK、trnL-trnF、trnH-psbA和rp 120-rps 12）进行了系统发育分析。关键结果叶形态是显着不同的类群，但形态变化的部分原因是适应某些环境条件下，每个人口居住。nDNA内转录间隔区和cpDNA的分子同源性在F. hiberniflorum和台湾var. formosanum，同时提出了流生植物、落花植物和阳生植物分类群的多系起源。所有样品从琉球南部（日本）和台湾聚类成一个单系群，这证实了土地配置理论，涉及第四纪陆桥形成和随后的碎片成岛。两个DNA数据集之间的不一致可能意味着渐渗杂交和/或不完全谱系分选的痕迹。结论流生植物、落英植物和阳生植物的出现可能是由于它们沿分布范围沿着第四纪陆桥层迁移后在岛屿上的隔离和随后对河岸、海岸峭壁和森林下层环境的适应。几乎相同的DNA序列加上高度不同的形态之间的这些类群表明，多样化是迅速的。
BACKGROUND AND AIMS Farfugium (Asteraceae) is a small genus that contains the two species F. japonicum and F. hiberniflorum and is distributed along a long archipelago in east Asia. The common taxon, F. japonicum, includes three varieties associated with a wide range of habitats, including forest understorey (sciophytes), coastal crag (heliophytes) and riverbed (rheophytes). Leaf shape is an important taxonomic character within this genus and is associated with the habitat. METHODS Twenty populations that included all Farfugium taxa were collected throughout its range. Leaf morphology was measured to determine differences amongst the taxa. Phylogenetic analyses based on sequences of the internal transcribed spacer of nuclear rDNA and four plastid DNA regions (matK, trnL-trnF, trnH-psbA and rpl20-rps12) were conducted separately. KEY RESULTS Leaf morphology was significantly different amongst taxa, but morphological variations were partly explained by adaptation to certain environmental conditions that each population inhabited. Molecular phylogenies for the nDNA internal transcribed spacer and cpDNA were consistent in classifying F. hiberniflorum and the Taiwanese var. formosanum, whilst suggesting polyphyletic origins for the rheophyte, sciophyte and heliophyte taxa. All samples from the southern Ryukyus (Japan) and Taiwan clustered into a monophyletic group, which corroborates the land configuration theory involving Quaternary land-bridge formation and subsequent fragmentation into islands. The incongruence between the two DNA datasets may imply traces of introgressive hybridization and/or incomplete lineage sorting. CONCLUSIONS The occurrence of rheophyte, sciophyte and heliophyte plants within Farfugium may be attributable to their isolation on islands and subsequent adaptation to the riparian, coastal crag and forest understorey environments, following their migration over the Quaternary land-bridge formation along their distribution range. Nearly identical DNA sequences coupled with highly divergent morphologies amongst these taxa suggest that diversification was rapid.