Interaction between Rhizophagus intraradices and Mycorrhizal Helper Bacteria in Response to the Control Efficacy against Soybean Root Rot

Soybean is one of the most economically important oil and food crops globally, valued for its rich content of proteins, lipids, vitamins, and multiple mineral nutrients, serving as a vital source of plant-based oil and high-quality protein. However, during cultivation, soybean is highly susceptible to infection by root rot pathogenic fungi. Biological control methods have demonstrated remarkable efficacy in reducing root rot incidence and have emerged as one of the most promising strategies for integrated management of soil-borne diseases. Arbuscular mycorrhizal fungi (AMF) can form symbiotic relationships with over 80% of plant species, effectively reducing disease incidence and severity. Mycorrhiza helper bacteria (MHB) regulate plant hormone signaling pathways, directly antagonize microorganisms harmful to AMF, control soil-borne pathogens. The synergistic interaction between AMF and MHB optimizes nutrient cycling, enhances crop resistance, improves soil ecological functions, and maintains biodiversity. In this study, MHB strains were isolated from the spore walls of Rhizophagus intraradices in soybean rhizosphere soil to investigate their effects on soybean biomass, rhizosphere bacterial community composition, and root transcriptome, as well as to explore the interactive effects of R. intraradices and MHB on soybean root rot suppression.