Phylogenetic Studies On Phyllostachys Edulis And Its Variation Based On Transcriptome Data

Phyllostachys edulis is a uniaxial scattered plant in the genus Phyllostachys,subfamily Bambusoideae,which is the longest cultivated,most extensive and economically important bamboo species in China.There are many varieties within the species Ph.edulis,and the morphological diversity is very rich,which are important germplasm resources.Most of the existing studies are based on single molecular markers,to explore the population genetic diversity of Ph.edulis and there there are few studies on the phylogenetic and evolutionary history of its varieties.In this paper,the number and morphological characteristics of the variaties in Ph.edulis were summarized through literature review and field investigations,the main variation characters were detected by analyzing the morphological markers,and the phylogenetic relationship was reconstructed based on transcriptome data.Moreover,the divergent time and the evolutionary history of the main morphological characters in these variaties were preliminary explored.This study can enrich people’s understanding of the phylogenetic history,establish theoretical basis to the conservation and utilization of germplasm resources for Ph.edulis and its varieties,as well as provide new insights into the dynamics and mechanisms of the diversification of bamboos.A new strategy of the phylogenetic reconstruction within species were also explored.The main results are as follows:1)Morphological analysis of the varieties.A total of 27 legitimate binomials of varieties in Ph.edulis were found.Cluster analysis and principal component analysis showed that the nine morphological traits concerned by this study can be divided into two major categories:color and physical shapes,among which culm type,culm color and leaf color are the main traits of variation.2)Phylogenetic analysis of the varieties.The maximum likelihood phylogenetic tree of the varieties was established by using low copy orthologous genes and the SNP dataset,respectively.Among them,the phylogenetic tree based on the SNP data set resolved the phylogenetic relationship better.The varieties and wild population samples formed highly supported monophyletic group,supporting the point that the varieties are derived from the Ph.edulis populations.Jiangxi may be the divergence central area of Ph.edulis.3)Evolutionary history analysis of the varieties.Molecular clock analysis indicated that rapid radiation events occurred about 0.4 mya in Ph.edulis.Ancestral character reconstruction analysis showed that trait variations such as culm type,culm color,and leaf color had evolved independently in most of the variaties.The morphological consistency between Ph.f.taokiang and Ph.f.huamaozhu is the result of convergent evolution.Biogeographic analysis showed that the phylogenetic relationship was inconsistent with the geographical distribution trend.The rapid differentiation and rich diversity in Ph.edulis populations may be related to the climate,hybrid introgression,gene flow,and its complex introduction and cultivation history.