Isolation, Identification And Diversity Analysis Of The Contaminating Fungi From The Edible Mushroom-growing Synthetic Wood Logs

Guizhou province and Liaoning province are the areas where the cultivation and production of edible fungi in our country are developing very fast,causing serious problems due to fungal contamination or disease.In this paper,from the geographical differences in Tongren City,Guizhou Provinc and Liaoning Province different places,collected Auricularia heimuer,Hypsizygus marmoreus,Grifola frondosa,Lentinula edodes,Pleurotus ostreatus,Pholiota microspora,Flammulina velutipes,in total 7 kinds of edible mushroom susceptible samples of 61,the disease tissue of the fungal separation and purification of culture,through morphological and molecular biology methods were used to identify and analysis of species diversity.The aim was to reveal the populations and hazards of contaminated or pathogenic fungi in the edible mushroom of the two provinces,and to provide theoretical basis for prevention and control of disease in edible mushroom cultivation and production.By means of sample's dilution plate and diseased tissue inoculation on medium for fungal isolation,totally 213 fungal isolates were generated,and further identified,they morphologically belong to 52 species of 23 genera,including 13 species of the genus Penicillium,8 species of Trichoderma,7 species of Aspergillus,2 species of Fusarium,2species of Sporothrix and 20 species of other genera.By rDNA-ITS and tubulin ?-tubulin gene sequence analysis,these 52 species were identified as 25 fungal genera,including 4undetermined species of the genera Phaeoisaria,Trichoderma,Fusarium and Calocera.The results of morphological and molecular identification implied that these fungi includes 7newly recorded species of China,namely Penicillium meridianum,Rhinocladiella similis,Graphium jumulu,Sporothrix variecibatus,S.stylites,Hawksworthiomyces lignivwora and Xenoacremonium falcatum,of which the two genera of Hawksworthiomyces and Xenoacremonium were newly recorded in China.The statistic analysis of the identified fungi showed that the diseased synthetic wood logs of the edible mushroom cultivation in the investigated areas of Guizhou and Liaoning provinces were mainly caused by 13 species of Penicillium,8 species of Trichoderma and 7species of Aspergillus.In terms of fungal isolation rate,the genus of Trichoderma accounted for 37.56%,which was the predominant infectious fungal group,followed by Penicillium(15.02%),Aspergillus(10.33%),Fusarium(8.45%),Sporothrix(4.70%)and Neurospora(4.23%),the other groups of fungi were responsible for the left 19.71% isolation rate.The results indicated that diverse fungi were associated with the fungal infection or contamination of the synthetic wood logs growing various edible mushrooms on the levels of fungal generaand species.It was also found that the contaminating or infectious fungi showed certain level of preference for the growing edible mushroom species and the synthetic wood logs,which were different in stuff composition.The three species of the genera Sporothrix and Sporothrix-like Hawksworthiomyces were firstly reported from the mushroom-growing synthetic wood logs in the world.These three species showed difference in preference for the edible mushrooms,in rank of priority of Flammulina velutipes,Pholiota microspora,Auricularia heimuer and Lentinula edodes.It was also found that the compositions of contaminating or infectious fungi were different in the Lentinula edodes-growing synthetic wood logs in Guizhou and Liaoning provinces.