Mortierella alpina bioinoculant potentiates native microbiota for soil borne disease suppression in Panax notoginseng cultivation.

Mortierella spp. is emerging as a potential biocontrol agent against soil borne diseases due to its antagonistic effects on pathogens and strong environmental adaptability. However, the mechanisms by which it restructures rhizosphere microbial communities to achieve sustained pathogen suppression remain largely unresolved. This study aimed to investigate whether exogenous application of Mortierella alpina could mitigate soil borne diseases through synergistic interactions with indigenous rhizosphere microbiota. To address this objective, we conducted a series of experiments to evaluate dual-season efficacy of M. alpina inoculation on root rot disease incidence, plant growth, and rhizosphere microbiome dynamics. High-throughput sequencing of 16S rRNA and ITS amplicons was employed to characterize microbial community shifts, while network analysis was used to elucidate correlations between community composition and pathogen abundance. Critical functional validation was performed through in vitro antagonism assays and sequential inoculation pot trials to confirm the roles of M. alpina-enriched microbial taxa. Results showed that the introduction of M. alpina reduced the incidence of P. notoginseng root rot by 85.71 % in the first season and increased seedling survival to 82.58 % in the second. This biocontrol effect was associated with the enrichment of Trichoderma spp. and Pseudomonas spp., which suppressed Ilyonectria cyclaminicola by 71.74 % and 54.73 %. Further analysis supported a strong association between M. alpina-modulated microbial communities and the reduction in pathogen abundance and disease severity. Collectively, M. alpina functions as an effective biocontrol agent against P. notoginseng root rot primarily by reprogramming the rhizosphere microbiome. This microbiome-mediated strategy provides a sustainable avenue for enhancing plant health and productivity.