Phylogenetic Relationships And Genetic Diversity In Paris (Liliaceae) Inferred From ITS, TrnL-F, And AFLP Analyses

There are 22 species in the Genus Paris of Family Liliaceae in China, with the south-western region as the distributing center. They are significant for phylogenetic research of Angiosperm. Our research work focused on two aspects: the genetic diversity and genetic differentiation-in Paris thibetica based on AFLP analyses; and the phylogenetic research through the analysis of ITS sequence.(1) ITS and trnL-F spacer sequence analysis: A phylogenetic analyses of 21 species and varieties of Paris were carried for the genetic delimitation, based on the sequence data of the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA. The analyses are performed using maximum parsimony and distance methods, with the Trillium grandiflorum and Trillium maculatuma being selected as outgroups. The ITS analyses indicates that the Paris is monophyletic and sect. Paris is basal to the rest of Paris. And the second clade consists of two subclades, section Kinugasa and subgenus Daiswa + section Axialis. The cladistic condition suggested that Paris dunniana is the most evolutional species. And some species (i. e. Paris marmorata and Paris luquanensis, Paris axialis and Paris daliensis) are closely related. The results support the classification of Paris proposed by Li, but the two subgenus should be modified. TrnL-F spacer is a lack of enough informative characters, we can't find more details of interspecific relationship. However, the strict consensus tree from the trnL-F spacer analysis also supports the classification of one genera. (2) AFLP analysis: We utilized AFLP to screen for genetic variation within Paris thibetica. AFLP analysis using 4 pairs of AFLP primers was carried out on 74 different samples from five populations of Paris thibetica located at EMEI Mountain, WAWU Mountain, and Pengzhou in Sichuan Province. Each primer pair produced 61～78 bands, and a total of 287 discernible DNA fragments were generated with 235 polymorphic bands (81.88%). In species level, the percentage of polymorphic bands (PPB) was 81.88%; Shannon's information index (I) was 0.3827. Nei's genetic diversity was 0.2490. Gene flow (Nm) was high (1.6870). The genetic identities between populations were similar (IN= 0.8877～0.9410). Genetic differentiation (Gst) among 5 populations detected by Nei's genetic diversity analysis was 0.2286. At variety level, the estimates of P. hibetica var. thibetica were PPB=78.40%, H=0.2849, I=0.4273, and the estimates of P. hibetica var. apetala were PPB=63.07%, H=0.2439, I=0.3603. As for P. thibetica, genetic differentiation coefficient among varieties (Gst) was 0.0726. According to the UPGMA cluster analysis, the differentiation of 2 varieties were significant. Two varieties of Paris thibetica were divided into two groups in the dendrogram. Samples from the same population and varieties mostly clustered in the same cluster. The result indicated that there were relatively low genetic differentiation among the two varieties, but high genetic diversity in Paris thibetica.