A Systematic Study Of The Genus Humicola And Its Genus Thermomyces

Humicola Traaen and Thermomyces Tsiklinsky belong to Deuteromycotina, Hyphomycetes,Moniliales, Dematiaceae. Only morphological comparison could not distinguish them very well,and some morphological characters are easily affected by environmental factors, thus it is difficult to reflect their real natural evolutionary relationship. In addition, the criteria of morphology do not form a standard classification system to differentiate these species. With the rapid development of computer technology and molecular biology, fungal research based on DNA sequences has being a prevailing method. Through combined molecular systematics with morphology comparison, a new classification system can be established to redefine the two genera, and clarify the taxonomic placement of cryptic or similar species in the fungal groups.Seventy-six Humicola-like strains were attained from Shandong Agricultural University, but only 31 strains belong to Humicola after ITS sequence-BLAST. Meanwhile, we still isolated and purified approximately different colony morphology 73 strains(including 11 thermophiles fungi)from 200 soil samples by using the agar plate dilution method which included 27 Aspergillus strains, 12 Penicillium strains, 7 Paecilomyces strains, 4 Fusarium strains, 4 Thermomyces strains,3 Corynascus strain, 2 Scytalidium strains, 2 Thermoascus strains, 2 Cochliobolus strains, 2Humicola strains, one Cunninghamella strain, one Anthostomella strain, one Cladosporium strain,one Diaporthe strain, one Nectria strain, one Myrothecium strain, one Malbranchea strain and one Mortierellomycotina strain based on ITS sequence-BLAST.The placement of Humicola genus was discussed using single gene(ITS) and mulit-genes(ITS, LSU, TUB) phylogenetic analysis and results indicated that it belonged to the family Chaetomiaceae. Furthermore, these Humicola strains were divided into two indepedent clades(genera), and one was still kept the old name as Humicola because of type species of Humicola,Humicola fuscoatra var. fascoatra(ex-type culture) and the sexual stages were Farrowia, and another was named after Neohumicola gen. nov., which sexual stage was some species of the Chaetomium. In our study, 11 Humicola strains were identified as 7 species, Humicola verruculosa?H. irregularis sp. nov.?H. brachypadi sp. nov.?H. pedunclensis sp. nov., three undetermined taxa, HSAUP 1915?HGUP 0905 and HGUP 1001. The new genus Neohumicola included 22 strains but they only were identified as 2 species, N. grisea var. grisea comb. nov.and N. jilongensis comb. nov. Four thermophiles strains were identified as Thermomyces lanuginosus, Eurotiomycetes, Eurotiales, Trichocomaceae based on morphological comparison and ITS sequence analysis.Combined molecular phylogeny with morphologic comparison, author made two taxonomic keys: one was to solve the classification of Humicola and Neohumicola in Chaetomiacceae on gneric level; the other was to clarify Humicola and Neohumicola spp. on species level. All specimens and cultures are deposited in the HGUP(Herbarium Guizhou University, Plant Pathology).