Research On Community Structure Of Ectomycorrhizal Fungi And Relationships With Environmental Characteristics In Abies Fanjingshanensis

Abies fanjingshanensis has garnered significant attention due to its unique habitat and limited population size.Studying the ectomycorrhizal fungi(ECMF)in the soil of A.fanjingshanensis is of great significance for understanding its growth and ecological adaptation mechanisms.This study focused on A.fanjingshanensis trees in young,middle-aged,and mature forests.High-throughput sequencing technology was employed to analyze the ECMF community in the soil,along with its relationship with plant community structure and soil physicochemical properties.The research results not only address the knowledge gaps regarding ECMF in A.fanjingshanensis but also provide a foundation for understanding the mycorrhizal symbiosis system,aiding in the conservation of this rare and endangered species.Furthermore,these findings offer valuable data support for the development of a suitable mycorrhizal ecological domain for the protection of A.fanjingshanensis.The main research findings are as follows:(1)A total of 1871 ECMF amplicon sequence variants(ASVs)were detected in the soil of A.fanjingshanensis.These sequences were classified into 3 phyla,5 classes,13 orders,34 families,and 60 genera.Basidiomycetes was the dominant phylum,Agaricomycetes was the dominant class,Agaricales was the dominant order,while Inocybaceae and Thelephoraceae were the dominant families.Inocybe and Tomentella were the dominant genera.(2)The soil of A.fanjingshanensis forests in the young,middle-aged,and mature stages yielded a total of 812,883,and 841 ASVs,respectively.Basidiomycota was the dominant phylum across all age classes,while Agaricomycetes,Agaricales,Inocybaceae,and Inocybe were the dominant class,order,family,and genus,respectively.LEf Se analysis revealed that Entolomataceae and Entoloma were significant ECMF groups in the soil of the young forest,whereas Hydnangiaceae and Laccaria were significant ECMF groups in the soil of the middle-aged forest.Tomentellopsis was a distinct ECMF group in the soil of the mature forest.(3)There were significant differences in the ECMF community among the young,middle-aged,and mature A.fanjingshanensis forests.The Bray-Curtis heterogeneity index of the ECMF community in the mature forest soil was significantly higher than that in the young forest soil.The richness index,Shannon index,Simpson index,and Pielou index of the ECMF community varied significantly between the young,middle-aged,and mature forests.The richness and Pielou index were significantly higher in the young forest compared to the mature forest,while the Shannon index was higher in the young forest compared to the mature forest.The Simpson index was higher in both the young and middle-aged forests compared to the mature forest.(4)Coexistence network analysis revealed that Inocybe had the highest degree of connectivity in the ECMF community network of the young forest,while Entoloma had the highest degree of connectivity in the network of both the middle-aged and mature forests.Additionally,the ECMF community network in the young forest exhibited the highest stability.The neutral community model indicated that the ECMF community construction in the soil of the middle-aged and mature forests of A.fanjingshanensis was more likely to be influenced by deterministic processes compared to the young forest.The C-score model confirmed that the ECMF community construction patterns in the soil of the young,middle-aged,and mature forests of A.fanjingshanensis were non-random.(5)The primary factors influencing the richness and diversity of the ECMF community in the young,middle-aged,and mature forests of A.fanjingshanensis differed.Plant richness was the primary factor affecting ECMF community richness across all age classes.Soil available phosphorus(P)was the primary factor influencing the Simpson index and Pielou index in the young and mature forests,while it affected the Shannon index in the young forest.Soil p H was the primary factor influencing the Shannon index in the middle-aged and mature forests,as well as the Pielou index in the middle-aged and mature forests.Soil carbon-to-nitrogen ratio(C/N ratio)was the primary factor affecting the Simpson index in the mature forest.(6)The factors significantly influencing the ECMF community structure in the soil varied among the young forest,middle-aged forests,and mature forests.In the young forest,Shannon index and plant richness,as well as soil available nitrogen,potassium,and phosphorus,significantly affected the ECMF community.In the mature forest,plant Shannon index and richness,along with soil total phosphorus and C/N ratio,significantly influenced the ECMF community.In the middle-aged forest,soil p H,available phosphorus,and available potassium significantly affected the ECMF community.These results indicate that soil available nutrients and plant community structure have a greater impact on the ECMF community in the young forest,while soil total nutrients and plant community structure play a more significant role in the mature forest,and soil factors affect the ECMF community in the middle-aged forest.