Effect of chlorpyrifos on bacterial community structure in pepper rhizosphere

Abstract:

[Objective] To understand the effects of chlorpyrifos (CPF) on soil bacterial community structure. [Methods] Both cultivable and uncultured bacterial communities were studied by plate method and terminal restriction fragment length polymorphism (T-RFLP). PRIMER-E was used to analyze the data generated by T-RFLP. [Results] At the first 30 days, cultivable bacteria in CPF-treated group were significant different from the control group (P<0.05). The numbers of cultivable bacteria were recovered after the 30th day. Based on the analyzed of T-RFLP data by PRIMER-E, bacterial community was mostly changed (Hae III: C3 (the control group on 30th day), Y0 (the 15 μg/g CPF-treated group on the first day), Z2 (the 150 μg/g CPF-treated group on the 20th day); HhaⅠ: Z0 (the 150 μg/g CPF-treated group on the first day)). ANOSIM indicated that no significant differences were found between different chlorpyrifos concentrations (Hae Ⅲ: Global R=0.041, P=0.168; HhaⅠ: Global R=–0.04, P=0.842), while significant differences were found between different sampling time (Hae Ⅲ: Global R=0.304, P=0.001; HhaⅠ: Global R=0.28, P=0.001). TRF239, TRF240 and TRF241 made the largest contributions to community abundance. Several representative bacterial communities such as Bacillus sp., Clostridium sp., Staphylococcus sp., Sarcina sp., Pseudomonas sp. were achieved by online blasting. [Conclusion] High concentrations of chlorpyrifos will have a great disturbance on soil bacterial community, which will inhibit the growth of rhizosphere bacteria and may suppress the growth of plants. Thus we should reduce the harm caused by repeated use of chlorpyrifos in time.