Assays of PCB congeners and organochlorine insecticides with the transgenic Arabidopsis and tobacco plants carrying recombinant guinea pig AhR and GUS reporter genes

Abstract

Certain congeners of polychlorinated biphenyls (PCBs) and organochlorine insecticides are ligands of aryl hydrocarbon receptors (AhRs) in animals. A recombinant guinea pig (g) AhR, XgDV, was constructed by fusing the ligand-binding domain of gAhR, the DNA-binding domain of LexA, and the transactivating domain of VP16. Then, the expression unit of β-glucuronidase (GUS) reporter gene regulated by XgDV was introduced into Arabidopsis and tobacco plants. When the transgenic Arabidopsis XgDV plants were cultured on Murashige–Skoog (MS) medium containing PCB congeners, the GUS activity in the plants increased toxic equivalent (TEQ)-dependently. The GUS activity in the transgenic Arabidopsis XgDV plants cultured on MS medium containing the organochlorine insecticide dieldrin was also induced. On the other hand, in the case of DDT, the GUS activity induced by 3-methylcholanthere in the plants decreased. The transgenic Arabidopsis XgDV plants detected 1000 ng g⁻¹ PCB126 in 1 g of soils. Thus the XgDV plants seemed to be useful for convenient assays of PCB congeners and organochlorine insecticides, without any extraction and purification steps.

Keywords:

• Polychlorinated biphenyl
• organochlorine insecticide
• guinea pig aryl hydrocarbon receptor
• transgenic plants.

Acknowledgments

The Hartley guinea pig liver was donated by Prof. Hitoshi Ashida of Kobe University. Ah-immunoassay kits were kindly provided by Dr. Shigeru Fujimoto of Japan EnviroChemicals, Ltd. This work was supported by Grants-in-Aid for Scientific Research A from the Ministry of Education, Culture, Sports, Science and Technology of Japan (no.17208029) and Bio-oriented Technology Research Advancement Institution.