| In this study,based on the traditional microbial plate isolation and culture and high-throughputsequencing technology analysis,this paper analyzed the composition of the fungal communities from the tree-hole soils in Huaxi District,Guiyang City and Qixingguan District,Bijie City in Guizhou Province.By the correlation analysis combining the biological factors and environmental factors,the differences of the fungal community composition among the tree-hole soils,endophytic fungi and the corresponding subsurface soil were explored,and the effects of different epiphytes and environmental physico-chemical factors on the composition of the fungal community of Robinia pseudoacacia,the following conclusions were as follows:There are obvious differences in culturable fungal community between the soil suspended in tree holes and the subsurface soils of Robinia pseudoacacia in Huaxi District,Guiyang city,Guizhou Province.Based on tthe morphological characteristics and molecular identification,the results showed that 315 fungal isolates were obtained from the soil suspended in the tree holes,which belonged to 19 species in 7 genera.Penicillium commune was the main dominant species,whose isolation frequency(IF)was 81.11% of the total isolates.In addition,totally 156 fungal isolates belonging to 18 species in 6 genera were obtained in subsurface soil.The results indicated that the fungal quantity and composition in the soil suspended of tree holes were obviously more than those in subsurface soil.Although Penicillium commune was also dominant species in the subsurface soil,whose IF was only 24.93% of the total isolates.Indexes of fungal diversity in the soil suspended,including Shanon-Wiener index(H=0.8291),Simpson index(D=0.3373),pielou index(J=0.2815)and richness index(R=1.33),were lower than those in subsurface soil.Some unique fungi,such as Cunringhamella elegans,Chaetopyrena penicillata,Humicola nivea,were isolated from the soil suspended in tree holes,not from the subsurface soil.By means of the statistical analysis,the similarity coefficient between the soil suspended and subsurface soil was low(CJ=0.2300).Based on high-throughput sequencing methods,the community composition and correlation analysis among the endophytic fungi,fungi from tree-hole suspended soil and from the subsurface soil of Robinia pseudoacacia in Huaxi,Guiyang,Guizhou Province were analyzed.The results showed that the dominant genus was Metarhizium in tree-hole suspended soil,and its relative abundance was 39.75%.The dominant genus of endophytic fungi is a genus with unclassified genus,and the relative abundance is 83.23%.However,the dominant genus of the subsurface soil is Mortierella,with a relative abundance of 38.58%.Analysis by FUNGuild software platform showed that the endophytes of Robinia pseudoacacia included the following ecological functional groups: plant pathogens,animal pathogens,endophytic fungi,fungal parasites,lichen fungi,fecal fungi,wood rot fungi andundecided saprophytic fungi.In addition,Mortierella,Fusarium,Metarhizium,and Phialophora were also found in the endophytic fungi of Robinia pseudoacacia,tree-hole suspended soil,and subsurface soil,which indicated that there exist a certain correlation between fungi of the tree-hole soils and subsurface soil.Based on the DNA metabarcoding technology,the fungi from the tree-hole soil samples of Robinia pseudoacacia holes with three epiphytes were studied and sequenced.123557 valid sequences were obtained and belonged to 7 phyla,19 classes,48 orders,89 families,146 genera and 196 species through the cluster analysis.The results indicated that different epiphytes have the obvious effect on the fungal community and the relative abundance of tree hole soil samples.On the order level,among the soil sample with Hydrangea chinensis as the epiphyte(H4),the main dominant order was Boliniaceae and its relative abundance was 86.47%;the next was Pleosporales and its relative abundance was 7.18%.Among the soil sample with Cichprium endivia as the epiphyte(H5),the main dominant order was Hypocreales and its relative abundance was 34.46%;the next was Cystofilobasidiales and its relative abundance was 33.15%.Among the soil sample with Achyranthes bidentata as the epiphyte(H6),the main dominant order was Hypocreales and its relative abundance was 39.38%;the next was Pleosporales and its relative abundance was 13.72%.Further comparison analysis showed that the fungal diversity of H5 and H6 were richer than that of H4.On the genus level,the common fungal genera from the tree-hole soil samples with three epiphytes were up to 65,of which,some fungi related to human and animal diseases were included,such as Trichosporon,Guehomyces,Cryptococcus,Cladophialophora,Rhinocladiella,Exophiala,Pseudallescheria and Veronaea;moreover,some fungi parasitizing insects or nematodes existed,such as Beauveria,Metarhizium,Acremonium,Clonostachys and Pochonia.The highest and lowest shannon diversity index of H4,H5 and H6 were H6(3.1697)> H5(2.4834)> H4(0.7090),and the highest and lowest simpson diversity index was H4(0.7521)> H5(0.1609)> H6(0.0650).The highest diversity was samples of H6,while the lowest diversity was samples of H4.There are a certain correlation of fungal community between soil suspended in tree holes and soil properties.The structures of fungal community from tree-hole soils in the same area were similar.The fungal communities of the samples collected in Huaxi and Bijie have similar clusters,respectively.Correlation analysis showed that some pathogens had obvious correlation with physicochemical factors.Cladophialophora had a significant positive correlation with TP,and Rhinocladiella had a significant positive correlation with TP.Mortierella and Penicillium were significantly and positively correlated with TN.Fusicolla genus and TK showed a significant positive correlation.Through the CCA analysis,there was a positive correlation between samples H4,H5 and pH,H1 were positively correlated with TP and TK,and H2 & H3 and H6 were positively correlated with TN. |
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