Effects of truffle inoculation on root physiology and mycor-rhizosphere microbial communities of Carya illinoinensis seedlings

Although they are a valuable class of edible ectomycorrhizal fungus, truffles(Tuber spp.) never-theless face significant difficulties in the development of their scale. As a type of high economic value nut-like economic forest tree, the pecan (Carya illinoinensis) serves as a natural host for truffles. However, the technology for tuberous mycorrhizal synthesis in pecan has not yet been developed, and it is still unclear how certain microbes affect this process. In this study, we inoculated the pecan root system with a suspension of truffle spores and investigated the growth physiology of pecan seedlings with various infestation levels, as well as changes in the soil's physicochemical properties and the makeup of the microbial community at the root level. The findings showed that tuber in-oculation significantly increased the peroxidase activity of the pecan root system, significantly de-creased the PH and effective phosphorus content of mycorrhizosphere soil, while increased the nitrate nitrogen content; and significantly increased the abundance and diversity of the mycor-rhizosphere soil fungal community. Different groups of fungal and bacterial markers were formed in the mycorrhizosphere of pecan seedlings at different levels of infestation; in the highly infested group, Rozellomycota and lasiosphaeriaceae were the difference marker fungi, and Xanthobacteraceae , Rhizobiaceae as well as Streptococcaceae were the difference marker bacteria; in the low-infestation group, sphaerosporella was differential marker fungi, Bacillus and Tumebacillus were differential marker bacteria; The fungal marker flora of the control group consisted of Chaetomium and Gil-maniella. Pseudomonas was the marker bacterial community. Additionally, These fungi included Collarina and Rozellomycota, several bacteria from the genera Pseudomonas, Gemmatimonas, and others showed highly significant relationships with changes in soil pH, effective phosphorus, and nitrate nitrogen. In conclusion, pecan-truffle mycorrhizal seedlings have the potential to create the ideal microbial community structure needed for mycorrhizal growth, and these microorganisms have the potential to significantly alter the PH, effective phosphorus content, and nitrate nitrogen concentration of the mycorrhizosphere soil. This research can contribute to our understanding of how the mycorrhizosphere microbial community evolves when exogenous mycorrhizal fungi infest host plants and can offer some theoretical guidelines for growing pecan-truffle mycorrhizal seed-lings.