Molecular Phylogeny And DNA Barcoding Of The Anamorphic Genera Of Orbiliaceae

Fungi in the Orbiliaceae family are ecologically and economically very important, this kind of fungi contain several important anamorphic genera of nematophagous hyphomycete, such as Arthrobotrys, Dactylellina, Drechslerella etc. However, due to the numerous genera and species’names, diverse morphology, and no obvious differences of microstructures among some species, at present, the molecular phylogenetic of this kind fungi is insufficient, there are some problems about the fungal molecular phylogenetic and species identification in this family. Seven genes were selected to constructed the ITS phylogenetic tree, which covered the most number of species, with the combined phylogenetic trees, to identify the phylogenetic species of anamorph genera of Orbiliaceae.Then based on the concept of DNA barcoding, we try to find out the appropriate genes as the supplement ITS genes to identify this kind of fungi. The main results are as follows:1) We selected66species,138strains, which covered5anamorph genera of Orbiliaceae, three of these are nematophagous hyphomycete, Arthrobotrys, Dactylellina and Drechslerella, the other two are non-predatory fungus, Dactylella and Pseudotripoconidium. In total, we got866available DNA sequences of anamorph genera of Orbiliaceae, combining with the related sequences that have been uploaded in NCBI database. Then we used ITS sequences to do the preliminary species identification and phylogenetic analysis, constructed the phylogenetic tree of3gene fragments, RPB2, TUB and TEF. Base on two phylogenetic trees,31new phylogenetic species were identified, which greatly enriched the biological diversity of anamorph genera of Orbiliaceae.2) According to ITS and multiple genes phylogenetic tree analysis, seven problematic strains that existed in the genus level were found, and in the species level, six strains have been mergered into clear species names.3) According to the successful rate of PCR and sequencing, interspecific and intraspecific genetic distances, species identification capability, we found RPB2gene was the best one, its successful rate of amplification and sequencing was moderate, its’ single gene phylogenetic tree topology was similar to multiple genes combination tree, and it shows the highest species identification ability, when used K2p modle to calculate the distribution of interspecific and intraspecific genetic distances in all DNA fragments, just an gap existed in RPB2fragment, and the rest of the fragments were characterized by large scale of overlapping. So we propose RPB2as an candidate gene with ITS, both ITS and RPB2are suggested as the DNA barcode of anamorph genera of Orbiliaceae.