Effects of dibutyl phthalate on microbial community and the carbon cycle in salinized soil

Dibutyl phthalate (DBP), a typical persistent organic pollutant, is of extensive attention because of its universal detection in soils and its impact on soil ecology. However, the ecological effects of DBP on ecologically fragile salinized soils are unclear, especially as soil salinization can result in soil degradation and thus affect the soil carbon cycle. Therefore, in this study, a typical salinized soil (agricultural soil in the Yellow River Delta) was selected and treated with DBP at different doses (1.0, 10, and 50 mg kg -1) and incubated for 30 d. The results revealed that DBP exposure significantly decreased the abundance of soil microorganisms. Molecular ecological network analysis showed that some taxa related to the carbon cycle gradually became key taxa in the network, changing the composition and structure of the bacterial community. The decrease of cbbLG, cbbLR and cex, and the increase of sga, glx and mcrA functional gene abundance affected carbon conversion. Molecular docking indicated that DBP could bind to soil invertase and beta-glucosidase proteins, and change the enzyme activity. These results emphasized the critical impact of DBP on microbial communities and carbon cycling in salinized soils, and will play an essential role in DBP ecological risk assessment.