The Multi-gene Phylogeny And Classification Of Chaetomiaceae

The fungi of Chaetomiaceae are widely distributed resource ascomycetes. Most of themcan produce cellulase, xylanase and laccase to decompose cellulose and lignin, and somespecies with the ability to produce biologically active substances which are effective againsttumor cells and as biocontrol materials, a few kinds can cause woody plant diseases or skindiseases for human being. The classification of Chaetomiaceae has an important theoreticalsignificance for effective utilization of such resources.In this study,1139plant residues, and196soil surface samples and animal feces indifferent ecological environment were collected in the17provinces including Shaanxi,Xinjiang, Beijing, Gansu, Inner Mongolia, Tibet and oth areas.Combined morphological characters and phylogenetic analysis of18S rDNA gene,28SrDNA gene, rDNA-ITS gene, EF-1α gene and cytb gene, phylogentics relationships havebeen carried out among the members of Chaetomiaceae. The main results as follows.1.139isolated strains were classified based on the morphological characters. There are19species belonging to Chaetomiaceae, among them16species were the members ofChaetomium,1of Corynascus, and the rest of Achaetomium.4new species and3new-recorded species were discovered, and29new combinations of Chaetomiaceae wereestablished in this study. In all the strains, Ch. globosum ranked first, account for61.87%ofthe total, the numbers of Ch. bostrychodes and Ch. murorum were the second, respectivelyaccount for7.91%and5.76%. The four new species, which were Ch. beijiangensis sp. nov.,Ch. chiifengensis sp. nov., A. microsporum sp. nov. and A. stellatis sp. nov., have beenidentified and described.2. Based on the phylogenetics analysis of18S rDNA gene,28S rDNA gene, rDNA-ITSgene, EF-1α gene and cytb gene, the phylogenetic relations among the species ofChaetomiaceae have revealed, in which the species of Chaetomium, Achaetomium,Corynascus, Thielavia, and Chaetomidium should be members of Chaetomiaceae. Thephylogenetic trees of multi-gene sequences revealed that Chaetomium, Thielavia, andChaetomidium did not belong to a evolution of single-source phylogenetically. Theclassification at present in genus level in Chaetomiaceae could not reflect natural phylogenetic relationships. New criteria for genus level in Chaetomiaceae should beestablished.3. The phylogenetic analysis of multi-gene sequences revealed that there was a closerelationship between the shape of ascoma/ascospores and molecular phylogeny. Therefore,the shape of ascoma and ascospores can be used as the main basis for the establishment of thegenera. The secretions and their color when the species were trained in petri dishes hadsomething to do with the phylogeny. The orifice of ascoma, the types and distribution of hair,and the shape of asci had nothing to do with the phylogeny. They should not be treated astraits for generic classification4. The morphological characteristics and multi-gene sequence phylogenetic traits revealedthat there were similar morphological characteristics in their ascomata, asci, ascospores andhairs among Chaetomium, Thielavia and Chaetomidium. Thielavia and Chaetomidium werethe same as Chaetomium of non-ostiolate. Based on the supporting of morphologicalcharacteristics and multi-gene sequences, Chaetomium, Thielavia and Chaetomidium shouldbe merged to form a new genus taxon. Chaetomium newly should be re-defined and re-described.5. The multi-gene sequence phylogenetics showed that there were different nucleotidesequence in the different strains of Ch. globosum. The different strains of Ch. globosum, non-single evolution group, were in the different branches of the phylogenetic trees. Present Ch.globosum is a species complex including different species.6. Ch. caprinum Bainier and Ch. bostrychodes were highly different in the palisade cellstructure and culture traits. They were also in the different branches of the multi-genesequence phylogenetic trees. Therefore Ch. caprinum Bainier and Ch. bostrychodes should beclassified in two species and restored its early independent status of species.7. There were considerable variation of the gene sequences of rDNA-ITS and EF-1α geneof Chaetomiaceae. Both of them could be used for phylogenetics of the group. Cytb genesequences is conserved in some extend between species, is not recommended as a kind of traitof the interspecific phylogenetic studies.