The Research On DNA Barcode Of Lepista

Lepista belongs to Basidiomycota,Agaricales,Tricholomataceae,which have tricholomatoid sporocarp and rough surface spores.Most species of Lepista have great economic value and medicinal value.The morphological of Lepista is similar to the genera Tricholoma,Clitocybe and Collybia,which often cause artificial identification error.Futhermore,the classification based on the morphological features is difficult to accurately reflect the phylogenetic relationship within Lepista.Therefore,it is necessary to look for a more accurate identification method.DNA barcode technology is a better way to solve the current problem.A total of 85 materials from 7 species of Lepista were used as test specimens.And the gene fragments that commonly used in fungal species identification or phylogenetic analysis were selected,i.e.rDNA-ITS,nrDNA-LSU,nrDNA-IGS,EF1-α,RPB2,RPB1 and mtSSU.The eukaryotic universal primers were used for amplification,sequencing and testing.The different candidate barcode sequences were analyzed by different methods.Then the best DNA barcodes were screened based on the result.The main evaluation criterions include intra-and inter-specific divergences,evaluation of the ease of test barcode sequence acquisition(PCR and sequencing success rate)and ability of species identification.The results showed that the intergeneric variation of ITS region was relatively conserved in the species,and there was obvious barcoding gap.The ITS region was easy to be amplified and sequenced,and the species could be distinguished from other Lepista species.The ITS region was believed as the best DNA barcode of Lepista.The phylogenetic tree of Lepista was constructed using ITS sequence.Based on molecular data,the results showed that the genus Lepsita was a polyphyletic group.The Lepsita species formed four clades.The morphological characters of the sporocarp and the spores were believed as the important keys for Lepsita.The species Lepista sordida was proved as a polyphyletic group.The findings have great significance for the species diversity of the genus Lepista.