Generation Of Novel Reporter Systems For The Indication Of Non-doxin-like PCBs&Ankin

Polychlorinated biphenyls (PCBs) are persistent organic pollutants damaging to human health and the environment. Techniques to indicate PCB contamination in planta are of great interest to phytoremediation.PCBs can be divided into two groups:dioxin-like PCBs and non-dioxin-like PCBs. In mammalian cells DL-PCBs are recognized by the aryl hydrocarbon receptor (AHR) system, while NDL-PCBs are recognized by pregnane Ⅹ receptor (PXR) system. Monitoring of DL-PCBs in transgenic plants carrying the mammalian AHR receptor has been reported previously. Herein, we report the biomonitoring of NDL-PCBs using the mammalian PXR receptor. In the transgenic Arabidopsis designated NDL-PCB Reporter, the EGFP-GUS reporter gene was driven by a promoter containing18repeats of the xenobiotic response elements, while PXR and its binding partner retinoid Ⅹ receptor (RXR) were coexpressed. Results showed that the expression of reporter gene was insensitive to endogenous lignans, carotenoids and flavonoids, but responded to all tested NDL-PCBs in a dose-and time-dependent manner. Two types of putative PCB metabolites, hydroxy-PCBs and methoxy-PCBs, displayed altered activation properties. The vascular tissues seemed unable to transport NDL-PCBs. Taken together, the reporter system may serve as a useful tool for biomonitoring the uptake and metabolism of NDL-PCBs in plants.Since the NDL-PCBs reporting system can monitor NDL-PCBs efficiently, we reconstruct the ligand binding domain(LBD) of PXR using the SOE PCR(gene splicing by overlap extension PCR) method. Replaced the LBD of PXR with an aunxin binding domain from the auxin receptor TIR1, aiming to develop a novol method to indicate auxin concentration in vivo.