Pyrosequencing reveals bacterial communities and enzyme activities differences after application of novel chiral insecticide Paichongding in aerobic soils

- The degradation characteristics and mechanism of IPP in soil C and H were studied.
- Soil enzyme activities and microbial population were studied after IPP application.
- The community composition differed in phyla and genus level after IPP-spraying.
- The increased and decreased genus in soils were different after IPP-spraying.

Paichongding (IPP) is a novel chiral insecticide developed in China. It has two chiral carbon centers, which lead to four stereoisomers (RR-IPP, SS-IPP, RS-IPP, SR-IPP). Large amount of insecticide application in modern agricultural production can lead to insecticide residues and pollution in soils, which can affect soil enzyme activity, microbial population, bacterial community and their composition. In this study, desalting muddy polder soil (soil C) and yellow paddy soil (soil H) were employed to investigate IPP degradation process, the effect on sole enzymatic activity and bacterial community in soils through pyrosequencing of 16S rRNA gene amplicons. The degradation rates of RS/SR-IPP were higher than RR/SS-IPP in soils. Moreover, after inoculation of IPP-degrading strain Sphingobacterium sp. P1-3 in soil C and H, degradation ratio of RR- and SS- IPP increased significantly. IPP had a serious impact on soil microbes. The microbial diversity decreased in soil C, while in H soil, the microbial diversity increased. The community composition also differed both in phyla and genus levels in soils. The phyla of Bacteroidetes was the most abundant phylum in soil C (66.2%) and H (44.1%) and the genus of Pseudomonas and Pseudorhodoferax increased in soil C, while Pseudomonas, Mycrovirga, and Brevundimonas were stimulated to increase in soil H after IPP application, respectively.