Effect of Arbuscular mycorrhizal fungi (AMF) inoculation on endophytic bacteria of lettuce

AMF have been found to benefit plant growth. However, it still lacks available evidence that AMF inoculation affects endophytic bacteria of lettuce. To complement this knowledge, a pot experiment was carried out to determine the effect of AMF inoculation on growth and the endophytic bacterial community of lettuce. This study investigated the characteristics of the endophytic bacterial community of lettuce roots using Illumina MiSeq high-throughput sequencing. The results showed that AMF increased the plant height (+30%), root length (+64%), root weight (+72%), and stem weight (+68%) of lettuce. The phylogenetic tree showed differences in the community composition of endophytic bacteria in lettuce. LEfSe analysis showed that the endophytic bac-terial communities of lettuce inoculated with AMF exhibited more biomarkers than those of lettuce not inocu-lated with AMF. According to molecular ecological networks, lettuce that had been inoculated with AMF had more stable and complex endophytic bacterial communities than those of lettuce not inoculated with AMF. The functional composition profiles indicated that many functions were enhanced, including environmental adap-tation and cell motility. Structural equation modeling (SEM) showed that inoculation with AMF had a significant effect on lettuce endophytic bacterial network structure and community function, the bacterial network structure being the largest positive contributor to bacterial diversity (P < 0.05). Overall, our findings provide new in-formation on the effects of AMF on the endophytic bacterial communities in the lettuce.