Functional characterization of the ABC transporter TaPdr2 in the tolerance of biocontrol the fungus Trichoderma atroviride T23 to dichlorvos stress

Abstract For successful biological control interactions, biological control organisms need to tolerate toxic chemical pesticides present in the environment. Dichlorvos (DDVP) is one of the most widely used organophosphorus pesticides and is also used as a model organophosphorus pesticide to understand the tolerance mechanism of biocontrol agent to chemical fungicides. In this study, we focused on the contribution of one ATP-binding cassette (ABC) transporter in Trichoderma atroviride that results in tolerance to DDVP stress. The gene encoding the protein, designated TaPdr2, was amplified from the T. atroviride T23 genome using homologous cloning and identified by induction to DDVP exposure. The sequence analysis of TaPdr2 predicted that this gene was a typical ABC-G transporter and may have functions, such as serving as a pleiotropic drug resistance protein (PDR) phenotype for xenobiotic tolerance and biocontrol traits. The key role of this gene in the tolerance to DDVP was demonstrated by the characterization of deletion mutants obtained by the ATMT-mediated knockout of homologous recombination. By analyzing the difference in growth phenotype between Δ TaPdr2 and the wild type (WT) strain, we found that Δ TaPdr2 led to a significant decline in Trichoderma tolerance to DDVP. Similarly, the ergosterol content in the Δ TaPdr2 cell membrane was also significantly reduced compared with the WT strain. The electrolyte leakage rate of the WT and Δ TaPdr2 under DDVP stress was higher than that of DDVP-free treatment. However, the electrolyte leakage rate was not significantly different between the mutant Δ TaPdr2 and the WT in the presence of DDVP. These data showed that the transporter TaPdr2 contributes to DDVP tolerance in T. atroviride T23.