基于matK基因的松属白皮松组分子系统发育分析

基于matK基因对松属(Pinus L.)白皮松组(sect.Parrya Myre)进行了分子系统发育分析.白皮松组为一个并系类群,因为白松组的成员与该组(包括越南的扁叶松(P.krempfii Lecomte))的亚洲成员形成一个强烈支持的分支(靴带值92%).在这个分支中,白松组的3个代表种形成一个稳定的单系,而白皮松组的亚洲成员之间系统发育关系不明确.扁叶松和西藏白皮松(P. gerardiana Wall.ex D.Don)聚在一起,但只有61%的支持率.虽然在以前4个cpDNA基因序列分析时五针白皮松(P.squamata X.W.Li)与白皮松(P.bungeana Zucc.ex Loud.)和西藏白皮松形成一个单系,但在本文的分析中三者的关系不明确.在邻接树和多数一致简约树上,北美的白皮松组成员形成一个支持率低的分支.北美的subsect.Balfourianae Engelm.亚组(包括P.aristata Engelm.)是一个单系,但支持率较低.美洲另外两个亚组subsect.Cembroides Englem.和subsect.Rzedowskianae Carv.的组间和组内关系不确定,它们在严格一致简约树上形成一个多歧分支.

Molecular Phylogeny of Section Parrya of Pinus (Pinaceae) Based on Chloroplast matK Gene Sequence Data

The molecular phylogenetics of sect. Parrya Myre of Pinus L. was analyzed based on chloroplast matK gene sequence data. The section was resolved as paraphyletic because members of the sect. Strobus were nested within a clade composed by the Asian members of the section, including the Vietnamese P. krempfii Lecomte, which was strongly supported with a bootstrap value of 92%. In this topology, the three sampled species of sect. Strobus formed a strongly supported monophyletic group, while their relationships of Asian species of sect. Parrya were not clear. P. krempfii was grouped with P. gerardiana Wall. ex D. Don with low bootstrap support. The relationships among the Asian members of the sect. Parrya, i.e. P. bungeana Zucc. ex Loud., P. gerardiana and the recently described endangered pine, P. squamata X. W. Li, was not resolved, although the monophyly of the three pines was strongly supported in the combined analysis of four cpDNA sequences. The topology of the neighbor joining tree revealed an assemblage of the American members of the section, which also appeared in the majority rule tree with weak bootstrap support. However, this assemblage was not resolved in the consensus tree of the parsimonious analysis. The American subsect. Balfourianae Engelm. formed a weakly supported group including P. aristata Engelm., while the relationships among and within the other two American subsections, Cembroides Englem. and Rzedowskianae Carv., were not resolved, as the members of them formed a polytomy in the consensus tree of the parsimonious analysis. The biogeographical implications of the results are also discussed in this paper.