Phylogeny of Salix subgenus Salix s.l. (Salicaceae): delimitation, biogeography, and reticulate evolution.
Phylogeny of Salix subgenus Salix s.l. (Salicaceae): delimitation, biogeography, and reticulate evolution.
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柳亚属 Salix s.l. 的系统发育
DOI：
10.1186/s12862-015-0311-7
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发表时间：
2015-03-04
影响因子：
3.4
通讯作者：
Chen JH
中科院分区：
文献类型：
--
作者：
Wu J;Nyman T;Wang DC;Argus GW;Yang YP;Chen JH
研究背景：柳属柳亚属Salix s.l.的分类和系统学研究。难以在柳属的亚属分类中，两个重要的形态特征（雄蕊数和芽鳞形态）的可靠性和进化意义尚未得到检验，柳属亚属的一个主分支的一个分离的新旧世界分布格局，之前的一项研究显示，缺乏合理的解释。为了研究这些问题，我们进行了系统发育分析的基础上，从4个质体（rbcL，trnD-T，matK，和atpB-rbcL）和两个核标记（ETS和ITS）覆盖所有亚属的柳，柳s.l.结果的所有部分亚属柳来作为准或多系的nrDNA和质体树的序列数据。质体发育成功地解决了柳属主要分支之间的关系，但亚属柳s.l.仍然很低。然而，在柳亚属中可鉴定出三个单系群：柳亚属的"主支"，新大陆种和旧大陆种是单系的; Triandroides分支组;和Pleuradenia分支亚属。而柳亚属内的nrDNA区域显示出更高的分辨率，他们没能解决次属的关系。广泛的，统计学上显着的基因树不一致，检测到跨nrDNA质体以及nrDNAETS-ITS同源性，表明网状进化或组内杂交。网络分析结果支持。多雄蕊和自由芽鳞的形态重建表明，多雄蕊和自由芽鳞代表柳属内的近形状态，并且在雄蕊数量和芽鳞形态上发生了几个显著的变化。不是单系的，和亚属的进化历史涉及多个网状事件，可能主要是由于杂交。文章题目柳亚属的划分。芽鳞形态和雄蕊数的进化不稳定性表明，这些性状是不可靠的分类依据。文章题目柳亚属的新、旧大陆间断分布。这似乎与第三纪的气候变冷有关，这切断了新旧世界血统之间的基因交换。
Background:The taxonomy and systematics of Salix subgenus Salix s.l. is difficult. The reliability and evolutionary implications of two important morphological characters (number of stamens, and morphology of bud scales) used in subgeneric classification within Salix remain untested, and a disjunct Old-New World distribution pattern of a main clade of subgenus Salix s.l., revealed by a previous study, lacks a reasonable explanation. To study these questions, we conducted phylogenetic analyses based on 4,688 bp of sequence data from four plastid (rbcL, trnD-T, matK, and atpB-rbcL) and two nuclear markers (ETS and ITS) covering all subgenera of Salix, and all sections of subgenus Salix s.l.Results:Subgenus Salix came out as para- or polyphyletic in both nrDNA and plastid trees. The plastid phylogeny successfully resolved relationships among the major clades of Salix, but resolution within subgenus Salix s.l. remained low. Nevertheless, three monophyletic groups were identifiable in subgenus Salix s.l.: the 'main clade' of subgenus Salix s.l., with New and Old World species being reciprocally monophyletic; the section Triandroides clade; and the subgenus Pleuradenia clade. While nrDNA regions showed higher resolution within subgenus Salix s.l., they failed to resolve subgeneric relationships. Extensive, statistically significant gene-tree incongruence was detected across nrDNA-plastid as well as nrDNA ETS-ITS phylogenies, suggesting reticulate evolution or hybridization within the group. The results were supported by network analyses. Ancestral-state reconstructions indicated that multiple stamens and free bud scales represent the plesiomorphic states within Salix, and that several significant shifts in stamen number and bud scale morphology have occurred.Conclusions:Subgenus Salix s.l. is not monophyletic, and the evolutionary history of the subgenus has involved multiple reticulation events that may mainly be due to hybridization. The delimitation of subgenus Salix s.l. should be redefined by excluding section Triandrae and subgenus Pleuradenia from it. The evolutionary lability of bud-scale morphology and stamen number means that these characters are unreliable bases for classification. The disjunct Old-New World distribution of subgenus Salix s.l. appears to be linked to the profound climatic cooling during the Tertiary, which cut off gene exchange between New and Old World lineages.
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影响因子：
56.9
作者：
Alsos, Inger Greve;Eidesen, Pernille Bronken;Brochmann, Christian
通讯作者：
Brochmann, Christian
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影响因子：
3.4
作者：
Chen, Jia-Hui;Sun, Hang;Yang, Yong-Ping
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Yang, Yong-Ping
影响因子：
4.1
作者：
Baldwin, BG;Markos, S
通讯作者：
Markos, S
影响因子：
3.4
作者：
ELMQVIST, T;AGREN, J;TUNLID, A
通讯作者：
TUNLID, A
影响因子：
3
作者：
Azuma, T;Kajita, T;Ohashi, H
通讯作者：
Ohashi, H