Preliminary Studies On Phylogeography Of Gynostemma BL. In Yunnan And The Origin Of Octoploid G. Pentaphyllum

Yunnan province is the most concentrated distribution and the most obvious biodiversity region of Gynostemma BL..7 species(14 populations)of Gynostemma BL. were collected in Yunnan province (a total of 420 individuals) to analysis the phylogenetic relationships, species formation, differentiation and geographical genetic structure by sequencing of the plastid intergenic spacers trnL-trnF, psbB-psbF and rpl20-rpsl2, and Hemsleya chinensis was selected as an outgroup in this study.We surveyed sequence variation of the chloroplast DNA (cpDNA) noncoding fragment trnL-trnF of Gynostemma BL. Insertion and deletions of two positions mainly due to the variation, he length of DNAtrnL-trnF sequence is 732bp-810bp.Five haplotypes were found by phylogenetic analysis of the trnL-trnF sequence in 7 species(14 populations) of Gynostemma BL. Base composition was with high A+Tcontent of 65.7%.Relatively high level of haplotype diversity (hd=0.725) and nucleotide diversity (Pi=0.290) were detected in Gynostemma BL. AMOVA analysis of the 14 populations were divided into two groups, one group is:DG, M, MG, XZ, MH, ML, MD; the other is DLCS20KM, DLCS, KMZWY, KMXS, DQ, ZT. FST is 1, indicating the degree of genetic differentiation among populations is very high.It be drawn from this study that the same species can be differentiated into different haplotypes, which indicated that a strong differentiation happened in the evolutionary process;the different species close to each other in distribution share the same haplotype. Some species of Gynostemma BL. with quite different morphological showed genetic relationship closely, and it indicated that they may have a common ancestor and the ancestral species may be polymorphic. In the late Quaternary, the north of Kunming-Xiaguan line have been affected by the violent fluctuations of the Quaternary glaciers in Yunnan Province from the history data.Because the mountain and valley in low altitude have not suffered temperature change,it provide a refuge for species of Gynostemma BL.,and it formed a center of the origin and evolution for Gynostemma BL.The Xishuangbanna and other places have been affected by the uplift of Qinghai-Tibet Plateau and the formation of the mountain range, and a complex mountainous and hilly topography has formed. Thus it affected formation and differentiation of Gynostemma BL.and the formation of special geographical genetic structure.In 14 populations of Gynostemma BL. involved in this study, only DLCS population is octoploid(8x),and the rest population are diploid (2x). There are 7bp insertion of TCTAAAT in the sequence from 79bp to 85bp base and 9bp deletion of AAAGATGTG in the sequence from 322bp to 330bp in the H2 with five populations., including the octoploid Gynostemma of DaliCangshan populations,which indicated the origin of octoploid Gynostemma is from the population within the H2 and it may origin from diploid Gynostemma by twice.