Metolachlor rice plants

Pesticides (aldicarb, carbofuran, isoproturon, chlorotoluron, metolachlor, mecc op, dichlorprop, MCPA, 2,4-D, methoxychlor, TDE, DDT, dieldrin, and DDE) in drinking water Bacterial endotoxins (lipopolysaccharides) in protein complexation Fungicide validamycin A in rice plants... 

Kawahigashi H, Hirose S, Ohkawa H, Ohkawa Y (2006) Phytoremediation of the herbicides atrazine and metolachlor by transgenic rice plants expressing human CYPlAl, CYP2B6, and CYP2C19. J Agric Food Chem 54 2985-2991... 

We also analyzed the metabolism of metolachlor in CYP2B6 rice plants. Metolachor was rapidly metabolized into its demetiiylated conqiounds in these plants and was subsequentiy metabolized into its conjugated conqiounds. These results showed that botii CYPlAl and CYP2B6 rice plants decreased the herbicide recidues in tiie plants more than tiie nontransgenic control plants. 

Analysis of Residual Metolachlor in CYP2B6 Rice Plants... 

Residual metolachlor in plants and in culture medium was analyzed by GC/MS and HPLC. Ten-day-old rice seedlings were transferred into a plant-box filled with 80 mL of MS liquid medium containing 30 pM metolachlor. After 1, 3, and 6 days of incubation under light at 27 °C, the amount of metolachlor in the plants and culture medium was analyzed. 

In this small-scale experiment, only a small portion of the added metolachlor was detected in toe plants most of toe metolachlor remained in toe culture medium. But CYP2B6 rice plants degraded toe metolachlor in toe culture medium and decreased its concentration rapidly. On toe sixth day of culture, toe amount of metolachlor degraded by toe CYP2B6 rice plants was 1.6 times that degraded by nontransgenic Nipponbare rice plants (Fig. 4). 

Figure 4. Analysis of metolachlor remaining in culture medium by gas chromatography. Ten-day-old rice plants were incubated in medium containing 30 pM metolachlor for 1-6 days.

We analyzed residual metolachlor in diree-month-old plants diemselves as well which were cultured with 9 L of medium containing 12 pM (3.4 ppm) metolachlor. Metolachlor was absorbed by the roots and accumulated in bodi CYP2B6 and nontransgenic rice plants. However, the amount of metolachlor in stems and leaves of CYP2B6 rice plants was only about one-third of that in nontransgenic Nipponbare rice plants (Table II). 

Transgenic rice plants expressing CYP2B6 rapidly decreased the amount of metolachlor present in both the plants themselves and the culture medium. Thus, such transgenic plants should be inq>ortant not only for developing herbicide-tolerant cultivars, but also for decreasing herbicide residues in rice. 

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