Taxonomic And Phylogenetic Studies Of Bambusicolous Roussoellaceae Fungi In Chengdu Area

The terrain of Chengdu slopes from northwest to southeast,forming a unique geomorphic feature of 1/3 hill,1/3 mountain and 1/3 plain.Its complex climatic conditions,with high rainfall and a humid year-round climate,make the area rich in natural resources,while nurturing a wide range of bamboo forests and the corresponding fungal groups.Some Bamboo fungi species can cause plant pathogen,the saprophytic and endogenetic fungi species play an important role in the ecological material cycle.The study of bamboo fungi is not only beneficial to the prevention and control of bamboo fungal diseases,but also to maintain the diversity and stability of regional ecological environment.Based on this,this paper selected 10 districts(counties and county-level cities)in Chengdu to collect relevant samples of bamboo fungi,and conducted traditional morphological study through microscopy,photographic records and plate making.The pure culture was obtained by single cell separation,DNA was extracted,and the corresponding sequences of ITS,LSU,SSU,rpb2 and tef1-α were obtained by PCR(Polymerase Chain Reaction).The maximum likelihood method and Bayesian analysis were completed by using relevant software,and the multi-gene phylogenetic tree was constructed to synthesize morphological characteristics and gene data.Determine the taxonomic status of fungi.The results are as follows: 1)In this thesis,a total of more than300 specimens were collected,and 349 pure cultures were obtained.After PCR amplification,319 ITS sequences were obtained.Gnen Bank sequence comparison showed that the species of Dothideomycetes were significantly more than that of coprochetes,including 3 orders(Pleosporales,Botryosphaeriales and Patellariales).More than 95% of the fungi were from Pleosporales.In the order Roussoellaceae,Roussoellaceae accounts for the largest proportion,and the species in this family are distributed worldwide,reflecting the geographical distribution of fungi in this family;2)Morphological analysis and multi-gene sequence alignment of 35 strains of Roussoellaceae were conducted in this study,and 21 different fungi from 3 genera were found,including 13 new species.Three known species(Roussoella hysterioides,R.neopustulans,R.yunnanensis)and five newly recorded species(R.japanensis;R.padinae,R.doimaesalongensis;New asexual species: R.siamensis;The new host species,Neoroussoella solani,increased the species diversity of the family by 20%;3)Host bias exists in some species,such as: Bambusicolaceae and Occultibambusaceae fungi parasitize bamboos obligately.Therefore,6 species closely related to bamboos were selected to be classified and found to contain 1 new genus(Pseudokeissleriella)and 6new species.In this thesis,bamboo fungi in Chengdu were collected extensively,and strains were classified and identified by the method of combining morphology and polygenetic phylogenetics,which enriched the resources of bamboo fungi in Chengdu and provided research basis and theoretical basis for further development and utilization.