Effect Of Several Medicinal Herbs On The Fungal Community Structure In A Hospital Grassplot Soil

As a common habitat for humans and microorganisms,the microbial composition of soil ecosystems is closely related to human health.In particular,the hospital grassplot soil is an important species repository of pathogenic fungi exposed in the hospital environment.Airborne transmission of these soil particles and dust carrying fungal spores increases the risk of nosocomial fungal infections,which has become an increasingly serious public health problem.Based on the view that soil microorganism and plant are closely related and regarded as the whole holobiont,it is of great scientific and practical significance to manipulate the composition and function of fungal community by changing plant species in hospital grassplot soil.In this study,five medicinal plants referring to Mirabilis jalapa,Artemisia argyi,Viola philippica,Plantago depressa and Perilla frutescens,which are rich in active metabolites and have a natural antibiotic action on human pathogenic fungi,were cultivated into the pot with hospital grassplot soil.Combined with plate isolation and culture and high-throughput sequencing methods,we observed the difference of fungal community composition and diversity and the changes of human potential pathogenic fungi in hospital grassplot soil during the three development stages of the tested plants(growing period,flowering stage and withering stage).Meanwhile,the differences of ecological guilds of the hub taxa of fungal communities in the hospital grassplot soil planted with different medical plants were analyzed.The aim is to find one or more medicinal plants that have a good control effect on the fungal community of hospital grassplot soil,especially the human potential pathogen,and to provide a reference for the introduction of specific plants to enhance the soil health of hospital grassplot and maintain public health safety in hospitals.The main research results are as follows:(1)Fusarium solani(33.33%)was the dominant species of culturable fungi community in the primary hospital grassplot soil,and Metarhizium(60.94%)was the dominant genus based on highthroughput sequencing.Through pot experiment,planting medicinal plants can significantly change the composition of fungal community in hospital grassplot soil,and significantly improve the community diversity.The composition of fungal community in hospital grassplot soil with different plants was different.At flowering stage,the dominant species of culturable fungi were Paecilomyces lilacinum(13.79%)and Humicola philophoroides(16.67%),respectively,in the soil samples planted with P.depressa and P.frutescens.Based on high-throughput sequencing,the dominant genera of each community were an unspecified genus of Xylariales(18.37%)and Mortierella(21.34%).There were also dynamic changes in the composition of fungal community in the three growth stages of the same plant.The dominant species of culturable fungal communities in the three development stages of P.frutescens were Cylindrocarpon olidum(16.67%),Humicola philophoroides(16.67%)and Talaromyces annesophieae(15.69%).Based on high-throughput sequencing,the dominant genera of each community were Mortierella(21.34%),an unspecified genus of Didymellaceae(47.22%)and an unspecified genus of Sordariales(12.67%).(2)Through pot experiment,the potential pathogenic fungi in the fungal community of hospital grassplot soil changed significantly.The results based on ISHAM-ITS sequence database annotated culturable fungi showed that the isolation frequency of potential pathogens in the samples planted with P.frutescens,M.jalapa and P.depressa in each growth period was lower than 46.67% of the primary hospital grassplot soil.FUNGuild platform was used to analyze highthroughput sequencing fungal community.The results showed that the relative abundance of animal pathogen(Including human potential pathogens)in each growth period of five medicinal plants was lower than 61.36% of the primary hospital grassplot soil.The results of ecological guild analysis of the hub taxa showed that only P.frutescens and P.depressa samples of 5 medicinal plants had no animal pathogen-associated guilds in the dominant and sub-dominant ecological guilds.(3)The characteristics of hospital grassplot soil physicochemical factors were changed after planting 5 kinds of medicinal plants in pot experiment.The changes of soil physicochemical factors were different with different medicinal herbs.Among them,p H,organic matter,total phosphorus,available phosphorus,total potassium and available potassium showed a downward trend,while total nitrogen and available nitrogen showed an upward trend.Correlation analysis revealed that hospital grassplot soil physicochemical factors were significantly correlated with a number of potential human pathogens,animal pathogen-associated guild and some hub taxa,suggesting to some extent that causing changes in soil properties is an important way for medicinal plants to regulate the composition and function of fungal community.In conclusion,all 5 tested medicinal plants had a moderating effect on fungal community composition in hospital grassplot soil,among them,P.frutescens and P.depressa have more obvious effect on pathogenic fungal communities and could be used as the alternative plants for the bioremediation of hospital grassplot soil in the future.