J Syst Evol ›› 2008, Vol. 46 ›› Issue (4): 573-585.DOI: 10.3724/SP.J.1002.2008.07097

• Research Articles • Previous Articles     Next Articles

Molecular phylogeography of alpine plant Metagentiana striata (Gentianaceae)

1 3Sheng-Yun CHEN*; 2Gui-Li WU *; 1 3De-Jun ZHANG; 1 3Qing-Bo GAO; 13Yi-Zhong DUAN; 1 3Fa-Qi ZHANG; 1Shi-Long CHEN *   

  1. 1(Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810001, China)

    2(Key Laboratory of Arid and Grassland Ecology, Lanzhou University, Lanzhou 730000, China)

    3(Graduate University of Chinese Academy of Sciences, Beijing 100049, China)
  • Received:2007-07-16 Published:2008-07-18

Abstract: Herbaceous plants have a short life cycle and are sensitive to environmental changes. Thus, they may serve as good models to elucidate historical processes of plant populations since Quaternary glaciations. Molecular phylogeographic analysis is a powerful tool to reveal the population history of plants and animals. To understand the geographic history of alpine plants in the Qinghai-Tibet Plateau, which is still poorly known, we surveyed sequence variation of the chloroplast DNA (cpDNA) noncoding fragment trnH (GUG)-psbA intergenic spacer throughout the range of Metagentiana striata (Maxim.) T. N. Ho, S. W. Liu & S. L. Chen, an annual and herba-ceous alpine plant in the Qinghai-Tibet Plateau and adjacent areas. Seven haplotypes were detected by analyzing 155 individuals from 13 populations of this species. One haplotype (A) was common and widespread, and three haplotypes (E, F and G) were unique in their populations. The center of haplotype diversity is located in the Hengduan Mountains of southeastern Qinghai-Tibet Plateau, with 2-3 haplotypes present in each of four popula-tions. In populations from the northeastern and eastern Qinghai-Tibet Plateau as well as from adjacent regions, however, only a single haplotype was found in each population, with different populations having different haplo-types. An analysis of molecular variance (AMOVA) for populations of M. striata showed that the genetic varia-tion mainly resided among populations (73.05%), and the estimates of interpopulation differentiation were very high (GST=0.805, FST=0.731, NST=0.859). Further, a significant phylogeographic structure was present (NST > GST, P<0.05) whereas the value of average gene flow was low (Nm=0.184) in the entire geographical range. Along with the nested clade analysis (NCA), our results suggested that the Hengduan Mountains of southeastern Qing-hai-Tibet Plateau served as a possible refugium during the Quaternary glaciations, and the interglacial or post-glacial range expansion by plants from the refugium followed by allopatric and past fragmentation shaped the present distribution patterns of haplotypes and populations.

Key words: alpine plant, cpDNA, Hengduan Mountains, Metagentiana striata, molecular phylogeography, refugium, trnH (GUG)-psbA