Enhancement of metabolizing herbicides in young tubers of transgenic potato plants with the rat CYP1A1 gene

Abstract

A rat P450 monooxygenase gene ( CYP1A1) was introduced into potato plants to enhance the metabolism of the environmental contaminants in subterranean organs. The CYP1A1 gene was kept under the control of the potato patatin promoter to enhance tuber-specific expression. A total of 106 transgenic plants (PAT1A1 plants) were obtained following selection by a resistance test to kanamycin and PCR analysis. PAT1A1 plants treated with 10% exogenous sucrose showed a higher activity of monooxgenase in the leaves than the non-transgenic plants. This indicated that the activity enhanced by 10% sucrose was due to the patatin promoter containing the sucrose-inducted elements. One representative transgenic plant, Ag2197, was selected on the basis of monooxgenase activity in the leaves and Western blot analysis. Ag2197 was found to accumulate a large amount of CYP1A1 mRNA and protein in the developing tuber but not in the mature tuber. The residual herbicides, atrazine and chlortoluron, were analyzed in the micro-tubers of Ag2197 and non-transgenic plants. The amount of residual herbicides in Ag2197 was much lower than that in the non-transgenic plant, indicating that the transgenic plant metabolized the herbicides to a detoxified form. The transgenic plants produced in this study might be useful for the phytoremediation of chemical pollution in the soil.

Biodegradation of atrazine in transgenic plants expressing a modified bacterial atrazine chlorohydrolase (atzA) gene

“…Although other transgenic plants that transform atrazine have been constructed previously (Inui et al ., 1999, 2001; Yamada et al ., 2002; Bode et al ., 2003), to our knowledge, this is the first example of the incorporation and expression of a substrate‐specific bacterial dechlorinating gene in plants that results in the complete detoxification of atrazine and its conversion to a single non‐chlorinated product. Although trichloroethylene‐transforming transgenic tobacco plants expressing mammalian cytochrome P450 2E1 have been reported, the primary degradation products were halogenated: chloral (2,2,2‐trichloroacetaldehyde) and trichloroethanol (Doty et al ., 2000).…”

Phytoremediation—An Overview

“…Initial attempts to engineer herbicide-tolerant plants utilized P450 cDNA from bacteria and mammals because of a lack of relevant plant genes (Morant et al, 2003). Transgenic rice (Oryza sativa) expressing human cytochrome P450 monooxygenases and transgenic potato (Solanum tuberosum) expressing either human or rat cytochrome P450 monooxygenases have shown enhanced metabolism and tolerance to a variety of herbicides (acetochlor, atrazine, chlorsulfuron, chlortoluron, imazosulfuron, methabenzthiazuron, metolachlor, norflurazon, pyributicarb), relative to nontransformed plants (Inui et al, 2000Ohkawa et al, 2001;Yamada et al, 2002). Introduction of human cytochrome P450 2E1, an enzyme that oxidizes a wide range of important halogenated hydrocarbon pollutants, into tobacco plants resulted in enhanced metabolism of trichloroethylene (TCE) and ethylene dibromide, widespread groundwater contaminants.…”

Genetically modified organisms and risks of their introduction

“…To secure atrazine resistance, potato and tobacco plants are modified by insertion into their genomes a P450 cytochrome CYP1A1 gene [82,83]. There are many reports on carcinogenic, immunotoxic, and embryotoxic properties of this compound (e.g., [84,85]).…”