Taxonomy And Phylogeny Of Tremella S.L.(Tremellales,Basidiomycota)

Tremella s.l.is widely distributed in the world,speices of the genus usually have gyno-carpic,gelatinous,waxy to cartilaginous basidioma.Economically some species have significantly edible and medicinal values,e.g.Tremella fuciformis and Naematelia aurantialba are commonly cultivated in China.Some species are dimorphic fungi that contain both a haploid unicellular yeast stage and a dikaryotic filamentous stage.The ecological habits of Tremella s.l.include symbiosis,parasitism and saprotrophism.In addition,the characteristics of Tremella s.l.are unstable with relatively small interspecific differences and diverse intraspecific variations,which led to difficulties on taxonomy of the genus.Systematic and comprehensive studies on the taxonomy and phylogeny of Tremella s.l.were not done in China,and the diversity of Tremella s.l.is still unknown.The studies on the taxonomy and phylogeny of Tremella s.l.can not only improve the understanding of the species diversity of the genus,but also provide important data for edible and medicinal fungal industry.Recent molecular phylogenetic analyses demonstrated that species in Tremella s.l.were nested in several genera including Carcinomyces(Carcinomycetaceae),Naematelia(Naemateliaceae),Phaeotremella(Phaeotremellaceae),Pseudotremella(Bulleraceae),Tremella s.s.(Tremellaceae)and some clades whose phylogenetic positions were undetermined in Tremellales(the Tremella clade I,the Tremella clade II and the Tremella clade III etc.).In this study,macroscopic morphology,microstructure observations,molecular data,ecological habit and geographical distribution were analyzed based on 411 specimens of Tremella s.l.and related groups.Muti-gene(ITS,n LSU,mt SSU,RPB1,RPB2 and TEF1)of the studied specimens were amplified by polymerase chain reaction.Based on the results of multi-gene phylogeny and morphological studies,the taxonomy of Tremellales was revised.The phylogeny was constructed for Phaeotremella and Tremella s.s.based on the combined ITS+n LSU+TEF1 dataset.Phylogenetic relationships within the two genera were outlined.The dried specimens were stained with a mixture of 2%Phloxine b and 5% KOH for photograph on taxonomic characteristics.Phylogenetic trees were constructed via Cipres Science Gateway(https://www.phylo.org),PAUP* 4.0b10,RAx Ml v7.2.6 and Mr Bayes 3.1.2 etc.The main results of this study were as follows:(1)Accordding to the phylogeny of Tremellales,14 families including three new families,Biatoropsisaceae fam.nov.,Lichenotremellaceae fam.nov.and Genolevuriaceae fam.nov.,were recognized;33 genera including three new genera,Bullertremella gen.nov.,Lichenotremella gen.nov.and Tremellopsis gen.nov.,were accepted;25 new combinations were proposed.(2)Species in Tremella s.l.were divided into eleven genera including Biatoropsis,Bullera,Bullertremella,Carcinomyces,Carlosrosaea,Lichenotremella,Naematelia,Phaeotremella,Pseudotremella,Tremella s.s.and Tremellopsis,and the phylogenetic relationships among these genera were analyzed.(3)Based on the results of morphological and molecular phylogeny,eleven species of Phaeotremella were identified including six new species,and their phylogenetic relationships were demonstrated.(4)30 species were identified in Tremella s.s.including 15 new species and their phylogenetic relationships were outlined.(5)Carcinomyces polyporinus,Naematelia aurantialba and Pseudotremella nivalis were identified and re-decribed based on studied materials.