Diversity And Phylogeography Of Keratinophilic Fungi In Southern Chin

Keratinophilic fungi is a kind of special fungal consortium that prefers various keratin-rich substrates and could use keratin as the only carbon and nitrogen source.Because of its ability to secrete keratinases that efficiently degrade keratin substrates,it often plays an important role in ecosystems and also has important potential applications in industrial,environmental protection and medical fields.These fungi are widely distributed and are especially abundant in soils with high human and/or animal activity.Because of their keratinophilic physiological functions,these microbes are often at the top of the trophic cascade of soil microbiota,and their composition and dynamics will have an important impact on soil biodiversity and ecological service functions.Many of these members are free-living taxa in soil,which provides an ideal model system for exploring the origin and evolution of such fungi.This study combination of hair baiting techniques and culture methods,the rDNA-ITS markers and morphological characterization were used(i)to analyze the species diversity of keratinophilic fungi in southern China,(ii)to explore the geographical distribution patterns,centers of origin and possible pathways of population expansion of free-living fungi using Purpureocillium lilacinum with high isolation frequency as a model,(iii)to explore the potential association between phylogenetic diversity and phylogeographical using the Arthrodermataceae as a model,(iv)to discover a large number of the new taxa through the addition of environmental stressor.The main results are as follows:(1)Species diversity of keratinophilic fungi in urban soils of southern ChinaIn this study,11,916 keratinophilic fungi were isolated,which belonged to 160 species in 4 phyla,10 classes,23 orders,42 families and 76 genera.The dominant species are Nannizzia gypsea and Chrysosporium pannicola,the dominant genera are Nannizzia and Chrysosporium,and the dominant families are Arthrodermataceae and Onygenaceae,all of these taxa are typical of keratinophilic fungi.The diversity analysis showed that the usage of chicken feathers as environmental stressor altered the fungal community composition in the samples,and reduced the diversity and evenness of fungal species in the samples and reducing the similarity of the communities.Correlation analysis showed that fungal community diversity was positively correlated with pH and C:N,but negatively correlated with TP,TN,SOM and OC.(2)Phylogeography of Purpureocillium lilacinumThis study estimated the genetic diversity of P.lilacinum and its geographic distribution pattern based on the global ITS dataset.At the intercontinental and climate zone levels,the highest genetic diversity at the Asia and the northern temperate zone,respectively.Divergence time estimation indicated that Hap 5,Hap 9,Hap 31 and Hap 32 from the Hainan,Guangdong,Jiangxi,Fujian regions of China in Asia were early divergence haplotypes.The neutrality test indicated that P.lilacinum is undergoing population expansion.These results supported that the southeastern coastal region of China is the original center of P.lilacinum,while the East Asian region adjacent to this origin is the center of the genetic diversity of P.lilacinum.The geographical distribution pattern of P.lilacinum showed that only one haplotype(Hap 1)was globally distributed,most haplotypes were distributed in Asia,while the few remaining haplotypes were scattered on other continents.(3)Phylogeny and phylogeography of the ArthrodermataceaeBased on 6577 sequences,serial analysis revealed that the genera Ctenomyces,Epidermophyton,Guarromyces,Lophophyton,Microsporum,and Paraphyton were all monophyletic groups,whereas Arthroderma,Nannizzia,and Trichophyton were polyphyletic.Among them,Arthroderma included at least four different lineages,except for Arthroderma Ⅱ,Arthroderma Ⅰ,Arthroderma Ⅲ and Arthroderma Ⅳshould be new lineage in Arthrodermataceae.Nannizzia contained at least two different lineages,Nannizzia Ⅰ and Nannizzia Ⅱ,but Nannizzia Ⅱ should be a new lineage in Arthrodermataceae.Trichophyton was divided into three clusters including T.benhamiae(Trichophyton Ⅰ),T.rubrum(Trichophyton Ⅱ)and T.mentagrophytes(Trichophyton Ⅲ)complexes;however,since Trichophyton Ⅱ and Ⅲ should be new lineages in Arthrodermataceae.The unclassified group,distributed in Japan and India,was incorrectly identified;it should be also a new lineage in Arthrodermataceae.In addition,the phylogenetic split network based on the ITS sequences provided strong support for the true relationships among the lineages in the reconstructed phylogenetic tree.A haplotype phylogenetic network based on the ITS sequences was used to visualize species evolution and geographic lineages relationships in all genera except Trichophyton.(4)Taxonomic study on new taxa of keratinophilic fungiChicken feathers,as environmental stressors,altered the composition of the microbiota in samples,selectively up-regulated the consortium of keratinophilic fungi and their position in the trophic cascade,thus made the acquisition of difficult-to-isolate and low-abundance taxa possible.Combining morphological characteristics and molecular phylogeny for accurate identification of potential new taxon,and using the new genera Solomyces Zhi.Y Zhang,Y.F.Han&Z.Q.Liang and Zongqia Zhi.Y.Zhang&Y.F.Han as examples,we explored the ecological specificity of the new taxonomic.The results showed that 28 new taxa were defined in this study,including two 2 genera and 26 new species.Among them,1 belonged to the Dothideomy cete s,6 belonged to the Eurotiomycetes,12 belonged to the Leotiomycetes,and 7 belonged to the Sordariomycetes.Ecologically,there are some differences between the genus Solomyces and the genus Zongqia and their related genus.In conclusion,the abundance of keratinophilic fungi in urban environments with close human activities is the result of their ecological adaptation,which also points to the direction of mining such resources.P.lilacinum originated along the southeast coast of China,and the neighboring East Asia is the center of genetic diversity of P.lilacinum,which lays the foundation for in-depth research on resource excavation and genetic conservation of this species.There are still polyphyletic taxa under the Arthrodermataceae.The new framework provided here for the phylogeny and taxonomy of Arthrodermataceae should prove to be useful for evaluating the results of preventive measures and interventions,as well as for conducting epidemiological studies.In addition,in phylogenetic analysis,phylogenetic splitting networks and haplotype phylogenetic networks can be an important complement to phylogenetic trees.In this study,a number of new taxa of fungi were isolated and classified using enrichment culture methods,which will help to resolve the diversity of fungal species in nature.