馬先蒿屬（Pedicularis）全球有600多種,，是列當科中最大的屬，其中有2/3以上的種類集中分布于喜馬拉雅—橫斷山區(qū),，該地區(qū)是其物種多樣化中心和特有中心之一,。東喜馬拉雅—橫斷山區(qū)特有的斗葉組（Sect. Cyathophora）僅有7個種（其中1個種存疑），卻擁有馬先蒿屬全部四種基本花冠類型,，它是研究馬先蒿屬花冠演化和物種形成的模式類群,。盡管斗葉組是一個單系類群已經(jīng)得到分子系統(tǒng)學(xué)研究的認可，但是長期以來其內(nèi)部各類群之間的系統(tǒng)演化關(guān)系存在許多問題和爭論,。
中國科學(xué)院昆明植物研究所生物多樣性與生物地理學(xué)重點實驗室郁文彬博士,，在李德銖研究員和王紅研究員的共同指導(dǎo)下，該研究通過較高密度的取樣,，基于核基因ITS和四個葉綠體片段聯(lián)合數(shù)據(jù),，運用貝葉斯推論（BI）、最大簡約法（MP）和最大似然法（ML）重建斗葉組的系統(tǒng)發(fā)育關(guān)系,，并利用SplitsTree進行網(wǎng)狀進化分析,。研究表明，核基因ITS構(gòu)建的系統(tǒng)樹和網(wǎng)狀結(jié)構(gòu)圖與傳統(tǒng)分類具有較高的一致性,；葉綠體聯(lián)合分析顯示四川分布的擬斗葉馬先蒿（P. cyathophyllodies）兩個居群的葉綠體基因組可能是從斗葉馬先蒿（P. cyathophylla）的祖先中捕獲而來,。斗葉組中的大王系（series Reges）的系統(tǒng)關(guān)系極為復(fù)雜,，推測可能是因不完全的譜系篩選,、雜交或基因漸滲透所造成。在斗葉組中,，無喙型和有喙型花冠是獨立演化,，而長管有喙型是由短管花冠演化而來。該研究較為準確地構(gòu)建了斗葉組種間的系統(tǒng)演化關(guān)系,，為進一步深入開展斗葉組,，尤其是大王系的物種形成機制和生物地理學(xué)打下了堅實的基礎(chǔ)。
上述研究結(jié)果以Incongruence between Nuclear and Chloroplast DNA Phylogenies in Pedicularis Section Cyathophora (Orobanchaceae) 為題于9月19日發(fā)表在PLoS ONE 上,。
該研究得到了中國科學(xué)院重點部署,、國家自然科學(xué)基金、中國科學(xué)院西部之光等項目支持,。（生物谷Bioon.com）
PLoS ONE doi:10.1371/journal.pone.0074828
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Incongruence between Nuclear and Chloroplast DNA Phylogenies in Pedicularis Section Cyathophora (Orobanchaceae)
Wen-Bin Yu, Pan-Hui Huang, De-Zhu Li mail, Hong Wang
Pedicularis section Cyathophora is a monophyletic group characterized by perfoliate leaf and/or bract bases at each node. This section comprises four series, corresponding to four general corolla types of Pedicularis, i.e. toothless, toothed, beaked and long-tubed corollas. In this study, we aim to reconstruct a comprehensive phylogeny of section Cyathophora, and compare phylogenetic incongruence between nuclear and chloroplast datasets. Sixty-seven accessions belonging to section Cyathophora and 9 species for other Pedicularis were sampled, and one nuclear gene (nrITS) and four chloroplast genes (matK, rbcL, trnH-psbA and trnL-F) were sequenced. Phylogenetic analyses show that the topologies and networks inferred from nrITS and the concatenated chloroplast datasets were incongruent, and the nrITS phylogenies and network agreed with the morphology-based taxonomy to some degree. The chloroplast genome of two Sichuan samples of P. cyathophylloides (E4 and E5) may show introgression from an ancestor of P. cyathophylla. Neither the nrITS dataset nor the concatenated chloroplast dataset were able to adequately resolve relationships among species in the series Reges; this is most likely due to incomplete lineage sorting and/or introgression/hybridization. The nrITS phylogeny indicates the beakless (toothed and toothless) and beaked galeas may have evolved independently within section Cyathophora, and the chloroplast phylogeny reveals that the long corolla tube with beaked galea is derived from the short one.
