Characteristics and Influencing Factors of Rhizosphere Microbial Communities of Tuber himalayense-Corylus heterophylla Ectomycorrhizosphere

Microbial diversity plays a crucial role within the plant rhizosphere ecosystem, serving as a pivotal indicator of plant health and stability. In order to explore the correlation between the growth of mycorrhizal seedlings and the nutrition and microbial diversity of the ectomycorrhizosphere, the soil of the ectomycorrhizosphere with different growth conditions was used as the research object, and the ITS1 region and 16S rRNA high-throughput sequencing technology were used to explore the inter-relationship. The findings indicated that the primary phyla within the rhizosphere soil microbial communities of various mycorrhizal seedlings were comparable, although their relative abundances varied. The relative abundance of Tuberaceae in good-growing mycorrhizal seedlings (CHTG) was 17.87% and 15.58% higher than in medium-growing (CHTM) and bad-growing (CHTB), respectively. Comparing the diversity indexes Chao1, Shannon and Simpson, it was found that CHTG had the lowest richness. Redundancy analysis (RDA)/canonical correspondence analysis (CCA) analysis revealed that Tuber was positively correlated with soil pH and negatively correlated with available nitrogen, organic matter, total nitrogen, total phosphorus, total potassium, available potassium, and available phosphorus. Rhizosphere core species analysis showed that symbiotic Ascomycota dominated the rhizosphere soil fungi, and the bacterial community was composed mainly of Proteobacteria. There was a positive correlation between most genera of bacteria and fungi. This study proved that in the bionic cultivation of Tuber himalayense-Corylus heterophylla, the growth of mycorrhizal seedlings can be promoted by adjusting the pH to weakly alkaline and enhancing the advantages of Plectosphaerella in the soil flora, without adding other nutrients, which provides a theoretical basis for the establishment of truffle plantations, soil improvement and ecosystem stability.