| Cantharellus cibarius is a kind of precious ectomycorrhizal fungi belonging to basidiomycetes,which has important medical and food value,economic value and ecological benefits,and is widely distributed in many areas of China.The unique evolutionary history and substantial economic value of C.cibarius has attracted considerable researchers to focus on its ecology,physiology and phylogeny.The study shows that bacteria exist widely in the process of isolation and different growth stages of C.cibarius,but its specific mechanism and function are not clear.In this paper,we studied the community diversity and composition of the symbiotic bacteria in the fruit bodies and mycosphere soil samples collected from Yangchang township,Wudang District,Mengguan township and Gaopo Township,Huaxi Distric,Guiyang City,Guizhou Province,using traditional isolation and culture methods combined with high-throughput sequencing technology.At the same time,the core microbiome method was used to identify the members of the core bacterial taxa in different parts of C.cibarius and analyze their composition and potential function differences,so as to clarify the distribution and potential function differences of the bacteria in different parts of the C.cibarius.In addition,the diversity and community composition of culturable bacteria in fruiting bodies and mycosphere soil samples were analyzed,and the potential functional strains of nitrogen fixation and phosphorus solubilization were screened.The main results are as follows:(1)There were abundant bacterial communities in fruit bodies and mycosphere soil of wild C.cibarius in different regions,but there were significant differences in species composition,core bacterial taxa membership identification and potential functional groups.Based on high-throughput sequencing technology,the bacterial community composition and diversity of fruit bodies and mycosphere soil in three different areas of Guiyang city,Guizhou Province,China were studied.The results showed that the main bacterial taxa colonizing fruit bodies were Proteobacteria and Bacteroidetes.The main complex species were Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium and Chitinophaga.Proteobacteria and Actinobacteria were the main bacteria in the mycosphere soil.Bradyrhizobium and Mycobacterium were more dominant genera.Meta Co MET platform was used to identify the core bacterial group members,and it was found that there were mainly 30 genera in the fruit bodies of wild C.cibarius,while there were up to 190 core bacterial taxa members in the mycosphere soil,which showed a great difference in composition.The functional groups of the core bacterial taxa in the fruit bodies were more concentrated in nitrogen nutrition and aromatic compounds degradation to support their own growth and development;bacterial taxa of the mycosphere soil preferred to decompose complex organic matter and absorb mineral nutrients,and this might prevent the infestation of pests and diseases in the soil environment to ensure the differentiation and growth of fruit bodies.Based on the traditional classical isolation method,the community composition and diversity of culturable bacteria in the fruit bodies and mycosphere soil of C.cibarius in three areas were analyzed.The results showed that the composition of bacterial community isolated from the fruit bodies of C.cibarius was highly similar,with the most bacteria of Pseudomonas,while the culturable bacteria in mycosphere soil was Bacillus.The potential functional groups of culturable bacteria in fruit bodies and mycosphere soil were similar to those of core bacteria taxa,and there was a trend of functional differentiation.(2)The bacteria community(diversity,relative abundance of dominant genera,isolation frequency of culturable bacteria and core bacteria)of fruit bodies and mycosphere soil in different regions were correlated with soil physical and chemical properties in different degrees.The results showed that soil p H value,available phosphorus(AP)and total phosphorus(TP)were most closely related to culturable bacteria,high-throughput dominant genera and core bacteria in fruit bodies and mycosphere soil,followed by organic matter(SOM).The abundance of Proteobacteria in the fruit bodies of C.cibarius is as high as73.12%,which is twice as high as that in the mycosphere soil.This difference may be related to the fact that the nutritional status of the mycosphere soil is lower than that produced by the fruit bodies.Redundancy analysis showed that the Shannon index and Simpson index of culturable bacteria and high-throughput bacteria in fruiting body were only positively correlated with soil p H,total nitrogen(TN),total phosphorus(TP)and available phosphorus(AP),and negatively correlated with total potassium(TK),available potassium(AK)and organic matter(SOM).However,the Shannon index of culturable bacteria and high-throughput sequencing bacteria community in mycosphere soil was positively correlated with organic matter(SOM),total nitrogen(TN),total potassium(TK),available nitrogen(AN),available potassium(AK)and available phosphorus(AP),and negatively correlated with p H value.The results showed that the bacterial diversity of fruit bodies was mainly affected by environmental physical and chemical factors such as p H,N and P,while the bacterial community diversity of mycosphere soil was affected by more soil physical and chemical factors.(3)There are abundant strains of nitrogen-fixing and phosphorus-solubilizing bacteria in fruit bodies and mycosphere soil.287 culturable bacteria were isolated from fruit bodies and mycosphere soil,of which 9 strains could grow stably on Burk’s nitrogen-free medium.The quantitative nitrogen fixation ability of N2 strain was determined preliminarily.It was found that N2 strain had the highest nitrogen fixation value(27.1768mg/L),followed by N4(24.2228 mg/L),N6(23.9274 mg/L),N7(23.9274 mg/L)and N8 strain(20.9734mg/L).Most of them belong to Pantoea,Klebsiella,Enterobacter,Paenibacillus,Pseudomonas and Rhizobium,indicating that they may have potential nitrogen fixation function.In this study,seven bacterial strains with the ability to degrade inorganic phosphorus were isolated by transparent circle method.Among them,strain P4 had the highest amount of phosphorus degradation(144.965 mg/L),followed by P2(123.96 mg/L),P5(111.595 mg/L)and P1(99.59 mg/L).They belong to Ewingella americana(P4),P.agglomerans(P2),P.fluorescens(P5)and E.asburiae(P1).It may play a certain role in promoting the growth and development of C.cibarius.In summary,this study revealed the community structure,diversity,core bacterial taxa,potential ecological functions and their relationship with soil physical and chemical properties of bacteria in different parts of the wild C.cibarius,and preliminarily screened some strains with the functions of nitrogen fixation,phosphorus solubilization and promoting growth,which provided basic information supplement and scientific basis for further explaining the relationship between C.cibarius and bacteria. |
PDF Full Text Request