Phylogenetic And Phylogeographic Study Of North American Clade Of Smilax Hispida Group

Smilax hispida group, a member of Smilax (Smilacaceae), semi-climbing shrub or shrub, branches slender needle-like spines as an important feature of the group species. Typical disjunct pattern of East Asia-North America, the group species includes S. sieboldii (the eastern Chinese mainland and Taiwan Island, Japan, Korean Peninsula), S. scobinicaulis (central and western China), S. hispida (in eastern North America), S. californica (northwestern North America), S. moranensis (Mexico) and S. jalapensis (Mexico, Guatemala, Honduras, Salvador, Nicaragua). To explore the distribution of the intermittent and complex evolutionary history of the origins of groups, I studied on the phylogeny and phylogeography of the North America clade of Smilax hispida group, using ITS and chloroplast regions (matK, rbcL, rpl16,ycf6/trnc, trnL/F), involving 27 populations. The main results obtained are as follows:1) Select three individuals from each species to reconstruct phylogeny tree of Smilax hispida group based on ITS matK, rbcL, rpl16, ycf6/trnc and trnL/Y. The result show that the Smilax hispida group forms a monophyletic group with strong support (MP bootstrap 100%, ML bootstrap 100%, posterior probability 1). Smilax hispida group North American groups forms a a class cluster with support (MP bootstrap 55%, ML bootstrap 75%, posterior probability 0.6),this cluster includes S. hispida、S. californica、S. moranensis and S. jalapensis.2) Population genetic and phylogeographic analysis based on cpDNA (ycf6/trnc, trnL/F) Identify 14differdent cpDNA haplotypes in 27 populations,12 populations (44.44%) have Glotypes diversity. The Appalachian Mountains have the highest level of haplotype diversity, these places may have refuges for S. hispida. Phylogeny MP tree and TCS network based on cpDNA data suggest infer that the southern Central American S. jalapensis as the first diverged species within American clade followed by S. californica, the close relationship between S. hispida and S. moranensis, and S. moranensis is the last diverged species.3) Further analysis based on nrITS region, identify 14 differdent generaltypes in 27 populations, 16 populations (59.26%) have diversity. Wisconsin and the south of Appalachian Mountains have the highest level of diversity, these places may have refuges for S. hispida. IBDWS analysis showed that there was a significant correlation between geographic distance and spatial genetic distance of Smilax hispida group North America clade (r=0.1739, P=0.0360, P<0.05). ITS generaltypes showed S. moranensis and S. jalapensis with the same distribution area share the same generaltype, cause of this phenomenon may be due to genetic introgression.4) The cordate-leaf type to the pandurate-leaf type variation can be found in the same population even in one individual. So can not be divided into two species based on this morphology evidence. ITS and chloroplast sequence analysis showed that differences in leaf morphology S. tamnoides and S. hispida at the molecular level have not a significant difference, and We support S. hispida and S. tamnoides should be the same species that is widely distributed in the eastern United States S. hispida.