Cupriavidus pinatubonensis AEO106 deals with copper-induced oxidative stress before engaging in biodegradation of the herbicide 4-chloro-2-methylphenoxyacetic acid

BMC Microbiology

Research Article

Danilo Pérez-Pantoja¹  Nanna Bygvraa Svenningsen²  Maria Rasmussen²  Ole Nybroe²  Mette Haubjerg Nicolaisen²  Mette Damgaard² 

[1] Programa Institucional de Fomento a la Investigación, Desarrollo e Innovación, Universidad Tecnológica Metropolitana, Ignacio Valdivieso 2409, San Joaquín, Santiago, Chile;Section for Microbial Ecology and Biotechnology, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C, Denmark;

关键词: Oxidative stress;    ROS;    ohr;    Copper;    PA degradation;    Cupriavidus pinatubonensis;   

DOI  :  10.1186/s12866-017-1119-y

 received in 2017-07-05, accepted in 2017-10-19,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundMicrobial degradation of phenoxy acid (PA) herbicides in agricultural soils is important to minimize herbicide leaching to groundwater reservoirs. Degradation may, however, be hampered by exposure of the degrader bacteria to toxic metals as copper (Cu) in the soil environment. Exposure to Cu leads to accumulation of intracellular reactive oxygen species (ROS) in some bacteria, but it is not known how Cu-derived ROS and an ensuing oxidative stress affect the degradation of PA herbicides. Based on the previously proposed paradigm that bacteria deal with environmental stress before they engage in biodegradation, we studied how the degradation of the PA herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA) by the model PA degrader Cupriavidus pinatubonensis AEO106 was affected by Cu exposure.ResultsExposure of C. pinatubonensis in batch culture to sublethal concentrations of Cu increased accumulation of ROS measured by the oxidant sensing probe 2,7-dichlorodihydrofluorescein diacetate and flow cytometry, and resulted in upregulation of a gene encoding a protein belong to the Ohr/OsmC protein family. The ohr/osmC gene was also highly induced by H2O2 exposure suggesting that it is involved in the oxidative stress response in C. pinatubonensis. The increased ROS accumulation and increased expression of the oxidative stress defense coincided with a delay in the catabolic performance, since both expression of the catabolic tfdA gene and MCPA mineralization were delayed compared to unexposed control cells.ConclusionsThe current study suggests that Cu-induced ROS accumulation in C. pinatubonensis activates a stress response involving the product of the ohr/osmC gene. Further, the stress response is launched before induction of the catabolic tfdA gene and mineralization occurs.

【 授权许可】

CC BY   
© The Author(s). 2017