Serendipita\nindica Drives\nSulfur-Related Microbiota in Enhancing Growth of Hyperaccumulator Sedum alfredii and Facilitating Soil Cadmium Remediation

Endophytic fungus Serendipita indica can bolster plant growth and confer protection against various biotic\nand abiotic stresses. However, S. indica<i>-</i>reshaped rhizosphere microecology interactions\nand root–soil interface processes in situ at the submicrometer\nscale remain poorly understood. We combined amplicon sequencing and\nhigh-resolution nano X-ray fluorescence (nano-XRF) imaging of the\nroot-soil interface to reveal cadmium (Cd) rhizosphere processes. S. indica can successfully colonize the roots of Sedum alfredii Hance, which induces a remarkable\nincrease in shoot biomass by 211.32% and Cd accumulation by 235.72%.\nNano-XRF images showed that S. indica colonization altered the Cd distribution in the rhizosphere and\nfacilitated the proximity of more Cd and sulfur (S) to enter the roots\nand transport to the shoot. Furthermore, the rhizosphere-enriched\nmicrobiota demonstrated a more stable network structure after the S. indica inoculation. Keystone species were strongly\nassociated with growth promotion and Cd absorption. For example, Comamonadaceae\nare closely related to the organic acid cycle and S bioavailability,\nwhich could facilitate Cd and S accumulation in plants. Meanwhile,\nSphingomonadaceae could release auxin and boost plant biomass. In\nsummary, we construct a mutualism system for beneficial fungi and\nhyperaccumulation plants, which facilitates high-efficient remediation\nof Cd-contaminated soils by restructuring the rhizosphere microbiota.