Colonization of phthalate-degrading endophytic bacterial consortium altered bacterial community and enzyme activity...

Phthalates (PAEs) are widely distributed hazardous organic compounds that pose threats to ecosystems and human health. Endophytic bacteria can effectively eliminate PAEs contamination risk. However, limited information is available regarding the impact of endophytic bacterial colonization on bacterial communities within plants. In this study, the endophytic bacterial consortium EN was colonized in lettuce by seed soaking, root irrigation, leaf spraying, and combined spraying-irrigation, resulting in a marked improvement in plant growth. The findings revealed that consortium EN colonization through combined spraying-irrigation exhibited superior degradation capability with 40.54% PAEs removal from soil. Meanwhile, the residual PAEs in lettuce decreased by 94.05% compared with the uninoculated treatment. High-throughput sequencing analysis indicated that colonization of consortium EN altered the bacterial community in lettuce. Specifically, the relative abundance of the dominant genus Pseudomonas was significantly higher than that in the uninoculated control (P < 0.01). Additionally, colonization enhanced the activities of peroxidase and catalase in lettuce, thereby improving plant resistance. This work offers a theoretical foundation for comprehending the mechanism underlying the bioremediation of PAEs contamination by endophytic bacteria in soil-plant system.