Molecular Phylogeny In Thelephora-Tomentella,and Population Genetics And Mitochondrial Heteroplasmy In Thelephora Ganbajun

Species in Thelephora-Tomentella are ectomycorrhizal fungi and some of them are of significant economic importance. Present species recognitions are mostly based on the morphologic characteristics of basidiocarp types. Respectively, the basidiocarp type of Thelephora spp. and Tomentella spp. are epigeous and resupinate. Based on ITS fragment, some studies found systematic problems may present in the existent classification system of species definition within these two close relative genera. Although species from these two genera can form a monophyletic group, they can not form as a monophyly within each genera separately. However, those statements relied on the phylogenetic analysis inferrend from individual gene fragment and that may not be accurate. In this study, based on several molecular markers, phylogenetic analyses were carried out on extensive origin Thelephora-Tomentella samples to show phylogenetic relationships among species. Furthermore, population genetic analyses were proceed to a well-known mushroom(Thelephora ganbajun) to infer its genetic diversity, population structure, dispersal, and reproduction pattern. Future resource protections and sustainable utilizations of this species will based on these information. At last, based on the appearance of mitochondrial heteroplasmy observed in population genetic analyses of Th. ganbajun, we verify this phenomenon in different methods and find out the distribution pattern of differnet mitochondrial components among individuals and popualtions.The main findings in this study are shown as follows:1. Phylogenetic analysis of Thelephora-TomentellaAccording to sequence similarity analyses between Th. ganbajun type specimen and one pure culture strain P2, we identified the taxonomic status of P2strain. By phylogenetic analysis, the position of Th. gnabajun is identified in the ITS tree. Four nuclear genes (28S rDNA,18S rDNA, TUB, and CHS2) and two mitochondrial genes (16S rDNA and12S rDNA) are used to implement phylogenetic analyses for Thelephora-Tomentella. Six genes’genealogical concordance phylogenetic species recognition analyses recognized21phylogenetic species and13of them inhabit in Yumnan province, including Thelephora terrestris and Thelehpora caryophyllea. This indicates a high level of biodiversity of Thelephora-Tomentella species in Yunnan. Moreover, GCPSR analyses also revealed two distinct species which had previously been thought as Th. ganbajun in mushroom transactions. The present status of the phylogenetic relationship between Thelephora and Tomentella is verified by involved epigeous and resupinate samples of Thelephora-Tomentella, and results show paraphyly. The GCPSR results supported the ITS fragment for a species identification barcode gene in this group and we recommended the28S rDNA and CHS2as candidates.2. Population genetic analyses in Th. ganbajunThree nuclear molecular markers (TEF1, TUB and CHS2) and two mitochondrial markers (COX3and12S rDNA) were used to conduct population genetic analyses for298identified samples of Th. ganbajun. The mitochondrial and nuclear dataset reflected the same population structure of this species. Results showed that the level of genetic diversity of Th. ganbajun in Yunnan province is high, the molecular variations mostly located within populations, the popultion status is stable and random mating, no obviously population genetic differences were observed among differnet populations, and genetic differences have no significant correlation with the geographical distances. Associations among alleles from differnet loci showed significant evidences of gene recombinations. In general, obvious gene flows were detected among different populaions. Spore dispersal and sexual reproduction play an important role in keeping population genetic diversity and population stability.3. The characteristic study of mitochondrial heteroplasmy in Th. ganbajunWe amplified the COX1gene in type specimen, P2strain and population samples, and found heterogeneous COX1sequences presented in these samples. This heteroplasmy causes by the presence of divergent sequences within the intron region of COX1. The distribution pattern of two type of COX1gene was complicated. When COXl-Ltype (347bp) distributed as the main component, the number of COX1-S type becomes trace. However, when COX1-Stype (341bp) distributed as the main component, the number ofCOX1-Ltype is a few less than that of COXl-Stype. Most heterogeneous samples have the dominated component of COX1-Stype. The proportion of two components in the cytoplasm is the type of "Trading off and taking turns". COX1heteroplasmy extensively presents in samples from different geographical populations. The quantitative relation between two types of COX1fragments rejects the hypothesis of horizontal gene transfer which mitochondrial COX3gene transfers into nuclear genome. In COX3gene, heteroplasmy is also found. Differ from COX1, heteroplasmy in COX3is caused by the point mutation In general, two mitochondrial genes support the occurrence of mitochondrial heteroplasmy in Th. ganbajun.