Studies On Culturable Fungi And Their Biological Activities In The Litter Of Xing'an Larch Forest

Fungi are important biological resources in nature with multiple biological activities.Therefore,they are used in crop pest control,cellulose and lignin degradation,biofertilizer,medical antibiotics,cosmetics,health products and other fields.There are unique and rich creatures in the forest of the Greater Hinggan Mountains,and in the forest litter there are still a large number of unexploited fungi.In this study,we isolated 30 culturable fungal strains from the litter of the forest of the Greater Hinggan Mountains using the particle dilution and used fungi ITS sequences to identify them.It was found that they belonged to 3 phyla,7 orders,11 classes,23 families,27 genera and 28 taxonomic units,and 8 strains of 30 ones were≤98.5% similar to known fungal ITS sequences.And these fungi have been undescribed before,and this study has witnessed the first-time report of their anti-phytopathogenic activity,free radical scavenging activities,and cellulose-degrading activities.We have performed biological activity screenings of the 30 strains.Five strains of phytopathogenic bacteria and fungi were used to test the antibacterial activity of six fermented crude extracts of the 30 strains.We found 23 ones have antibacterial activities,four of which,strain SGSF836（Paraconiothyrium cyclothyrioides）had stronger antibacterial activities and broader antibacterial spectrum.The antioxidant activity of six fermentation crude extracts of the 30 ones was tested by using DPPH radical scavenging method,and for the first time,strains SGSF445（Pyrenochaeta sp.,95% ITS similarity）,SGSF953（Umbelopsis vinacea）,SGSF961（Peyronellaea prosopidis）and SGSF980（Xylomelasma sordida）had been found of strong free radical scavenging activities.Of which,strain SGSF953 had two active compounds（Rf values:0.78,0.89）.By using Congo red staining,strain SGSF982（Rhinocladiella atrovirens,93% ITS similarity）was found to have strong cellulose degrading activity for the first time,and the ratio of hydrolytic circle to colony diameter was the largest for this strain（1.92±0.75）.Through the screening of phosphate-solubilizing activities six fungal strains were found to have phosphate-solubilizing activities,and for the first time,the strain SGSF806（Leptosphaeria biglobosa）and the strain SGSF830（Phacidium dicosmoanum）were found to have stronger phosphate-solubilizing activities.In this study,several strains were identified to have good biological activities,including new activities of undescribed fungi and new activities of known species.It is expected to provide alternative strains and theoretical basis for further research on the biological activities of fungi and the exploitation of fungal resources in the forest of Greater Hinggan Mountains.