Arbuscular mycorrhizal fungi promote ginseng biomass, ginsenosides, and shape rhizosphere soil microbial communities to varying degrees under different phosphorus levels

Ginseng (Panax ginseng C. A. Mey.) is a vital medicinal and industrial crop in China. Arbuscular mycorrhizal fungi (AMF) enhance plant phosphorus (P) absorption, but how they respond to varying P supply levels remains unclear. Ginseng as a host was inoculated by Rhizophagus intraradices (RI), Funneliformis mosseae (FM), and their co-inoculation MIX (RI and FM) in compartmented rhizoboxes, and grown under low, medium, and high phosphorus conditions. The mycorrhizal colonization, plant biomass, photosynthetic pigment content, saponin accumulation, phosphatase activity, P uptake and rhizosphere microbial community composition were determined. It was indicated that inoculation with AMF improved the fresh weight, stem length, photosynthetic pigment and saponin content of ginseng significantly. Interestingly, the influence of AMF species on ginseng exhibited variation with distinct gradients of soil phosphorus availability. Meanwhile, AMF symbiosis increased the bacterial and fungal diversity significantly and promoted deterministic processes of rhizosphere microbial community construction. Among them, the dominant groups were Proteobacteria (34.17 %-50.08 %), Acidobacteriota (8.75 %-12.57 %) and Ascomycota (47.44 %-75.22 %), whose abundance variations were significantly correlated with soil phosphorus indicators. Predictions from KEGG and FUNGuild databases revealed that AMF up-regulated amino acid metabolism, signal transduction and lipid metabolism in rhizosphere microorganisms significantly. The results above suggested AMF mediated the activation and turnover of soil phosphorus through mycelial network, which significantly improved the yield and quality of ginseng, and optimized the phosphorus efficiency by regulating the rhizosphere microbial community, and its potential for phosphorus resource management deserves to be explored deeply in green planting of ginseng.