Study On Oligotrophic Fungi In Understory Litter

The Greater Hinggan mountains have a broad forest coverage area.A large number of undeveloped fungal resources under the forest,and their secondary metabolites are very rich.Oligotrophic fungi are one kind of the important microorganisms,which not only play a special role in regulating the ecosystem,but also are important usable resources.There are abundant resources of oligotrophic fungi in China,but they are rarely researched.Based on the above research background,this study carried out a study on the oligotrophic fungi of litters under the forests of Greater Hinggan mountains,and evaluated their taxonomy,activity and secondary metabolic potential,in an attempt to obtain active fungal resources with deserving research potential.In this study,104 litter samples were collected from the Greater Hinggan forest,340 strains of fungi were isolated,and 50 oligotrophic fungi were obtained after screening and identification.They belonged to 35 genera and 39 taxa.Of them,seven suspected new strains were found.According to the results of antimicrobial activity and antioxidant activity,five strains of fungi were found to be active.With respect to the antimicrobial activity,the strains SGSF052,SGSF130 and SGSF178 had the activity.With respect to the antioxidant activity,the strains SGSF115 and SGSF058 had the strongest activity,and they had 2 and 3 antioxidant compounds,respectively.Two of the 5 active strains(SGSF052 and SGSF130)were further studied.The strain SGSF052 was named as Myxotrichum albicans sp.nov..According to its exclusive white colony,the strain SGSF052 had hyaline and dichotomously branched conidiophores and hyaline and cylindrical conidia.Moreover,pH value(pH 4.0-10.0)had no significant influence on its growth of colony.The strain SGSF130 was a new species of Parapyenchaeta genus.In conventional fermentation,it could produce at least four major secondary metabolites.By genomics research,it had 71 biosythetic gene clusters for secondary metabolites.Sixteen of them could be identified as its type.NPRS and T1 PKS were the main types.The chemical structures of the four secondary metabolites were predicted.This indicates that the most biosythetic gene clusters for secondary metabolites of strain SGSF130 should be cryptic,which needs to be activated and further explored.In this study,7 new oligotrophic litter fungi were found and cultured.Five of them had antimicrobial or antioxidant activities.A new taxonomic fungal species Myxotrichum albicans was erected.Parapyenchaeta sp.SGSF130,an active fungus with good potential of secondary metabolism,was cultured and found.It provided an alternative strain for the further development and utilization of oligotrophic litter fungi.