Shifts in indigenous microbial communities during the anaerobic degradation of pentachlorophenol in upland and paddy soils from southern China

Abstract

Pentachlorophenol (PCP) is a common persistent pesticide in soil that has generated a significant environmental problem worldwide. Therefore, anaerobic degradation of PCP by the soil indigenous microbial community has gained increasing attention. However, little information is available concerning the functional microorganisms and the potential shifts in the microbial community associated with PCP degradation. In this study, we conducted a set of experiments to determine which components of the indigenous microbial community were capable of degrading PCP in soils of two land use types (upland and paddy soils) in southern China. Our results showed that the PCP degradation rate was significantly higher in paddy soils than that in upland soils. 16S ribosomal RNA (rRNA) high-throughput sequencing revealed significant differences in microbial taxonomic composition between the soil with PCP and blank (soil without PCP) with Acinetobacter, Clostridium, Coprococcus, Oxobacter, and Sedimentibacter dominating the PCP-affected communities. Acinetobacter was also apparently enriched in the paddy soils with PCP (up to 52.2 %) indicated this genus is likely to play an important role in PCP degradation. Additionally, the Fe(III)-reducing bacteria Clostridium may also be involved in PCP degradation. Our data further revealed hitherto unknown metabolisms of potential PCP degradation by microorganisms including Coprococcus, Oxobacter, and Ruminiclostridium. Overall, these findings indicated that land use types may affect the PCP anaerobic degradation rate via the activities of indigenous bacterial populations and extend our knowledge of the bacterial populations responsible for PCP degradation.

Microbial Community’s Dynamic Response to Fomesafen Usage in Chernozems of Northeast China

“…The application of a pesticide can effectively prevent disastrous losses of grain yield and promote economic growth in the agricultural industry, but its degradation is affected by many factors, including soil type, pH, organic matter content and soil microbial communities. We speculate that there is consistency in the effects of fomesafen [7,8]. Previous authors have reported a residual half-life of fomesafen of 133 days when used in a soybean field of anthrosols in Hangzhou, and of 14.2 days when used in a soybean field of anthrosols in Chuzhou [9].…”

“…The pH was determined via the potassium chloride leaching solution method. The organic matter content was determined via the potassium dichromate heating oxidation method [7]. The whole nitrogen used was potassium borate with copper sulfate as the selenium powder, and the automatic analyzer used was determined by nitrogen analysis.…”