Abstract
Arbuscular mycorrhizal fungi (AMF) have the potential to enhance plant tolerance to abiotic stresses. However, the impact of AMF on the rhizosphere bacterial community of tobacco under conditions of low nutrient availability remains unclear. This study investigated the influence of inoculating Claroideoglomus etunicatum on the tobacco rhizosphere bacterial community and the microbial mechanisms by which AMF enhanced plants antioxidant capacity, employing Illumina MiSeq high-throughput sequencing. The findings indicated that AMF significantly increased both the aboveground and belowground fresh weight, as well as the plant height of tobacco. AMF inoculation led to elevated activities of catalase (CAT) and superoxide dismutase (SOD), a reduction in malondialdehyde (MDA) content, and an overall enhancement of the plants antioxidant capacity. Phylogenetic analysis demonstrated that AMF modified the bacterial community structure and significantly enriched beneficial rhizosphere bacteria, predominantly from the phyla Proteobacteria, Chloroflexi, Actinobacteriota, and Myxococcota, thereby facilitating tobacco growth. The network analysis revealed that the incorporation of arbuscular mycorrhizal fungi (AMF) contributed to increased stability within the bacterial community, enriched species diversity, and more intricate ecological networks. AMF enhanced interactions and positive correlations among bacterial species, indicating that heightened microbial synergy is associated with improved symbiotic relationships. Furthermore, the structural equation model demonstrated that AMF bolstered the plants antioxidant capacity by modulating the rhizosphere bacterial community. This study elucidates the impact of AMF on the tobacco rhizosphere bacterial community, providing a theoretical basis for promoting tobacco growth.