Biodegrading Two Pesticide Residues in Paddy Plants and the Environment by a Genetically Engineered Approach

Abstract

Accumulating pesticide (and herbicide) residues in soils have become a serious environmental problem. This study focused on identifying the removal of two widely used pesticides, isoproturon (IPU) and acetochlor (ACT), by a genetically developed paddy (or rice) plant overexpressing an uncharacterized glycosyltransferase (IRGT1). IRGT1 conferred plant resistance to isoproturon–acetochlor, which was manifested by attenuated cellular injury and alleviated toxicity of rice under isoproturon–acetochlor stress. A short-term study showed that IRGT1-transformed lines removed 33.3–48.3% of isoproturon and 39.8–53.5% of acetochlor from the growth medium, with only 59.5–72.1 and 58.9–70.4% of the isoproturon and acetochlor remaining in the plants compared with the levels in untransformed rice. This phenotype was confirmed by IRGT1-expression in yeast (Pichia pastoris) which grew better and contained less isoproturon–acetochlor than the control cells. A long-term study showed that isoproturon–acetochlor concentrations at all developmental stages were significantly lower in the transformed rice, which contain only 59.3–69.2% (isoproturon) and 51.7–57.4% (acetochlor) of the levels in wild type. In contrast, UPLC-Q-TOF-MS/MS analysis revealed that more isoproturon–acetochlor metabolites were detected in the transformed rice. Sixteen metabolites of isoproturon and 19 metabolites of acetochlor were characterized in rice for Phase I reactions, and 9 isoproturon and 13 acetochlor conjugates were characterized for Phase II reactions in rice; of these, 7 isoproturon and 6 acetochlor metabolites and conjugates were reported in plants for the first time.

Degradation of acetochlor and beneficial effect of phosphate-solubilizing Bacillus sp. ACD-9 on maize seedlings

“…Hence, these bacteria may be suitable for the treatment of wastewater with high acetochlor concentrations. Acetochlor is commonly applied to maize farmland at the recommended rate of 2.2 kg/ha (Oliveira et al 2013), 1.05-1.47 kg ai/ha (Norsworthy et al 2019) or 0.52-0.98 mg/kg (Su et al 2019). Hence, the acetochlor concentration in the natural environment is relatively low.…”

S-Glycosylation of Fluensulfone in Tomatoes: An Important Way of Fluensulfone Metabolism

“…This is similar to the symptoms caused by pesticide stress such as atrazine, isoproturon, and acetochlor. 9,14 On the contrary, after exposure for 7 d, the growth of the shoots was more inhibited than the roots, especially the fresh weight of the stems and leaves. After exposure to 2 mg/L FSF for 7 d, the chlorophyll content was significantly reduced, and the stems shrank and turned brown (Figure 1C,E).…”

“…Tomato (Solanum lycopersicum "Ailsa Craig") seeds were surface-sterilized with 5% H 2 O 2 . 9 After germination, seedlings were hydroponically grown in Hoagland's nutrient solution at a temperature of 25/20 °C (day/ night), a light intensity of 200 μmol m −2 s −1 , and a 12/12 h day/night rhythm. 12 Six tomato seedlings with approximative growth at two-leaf stage were transplanted in each 2 L plastic pot; the nutrient solution was renewed every 2 days.…”

“…7 For example, isoproturon, an herbicide, proceeds O-and Nglycosylation in rice and wheat. 8,9 According to the reasonable reaction site of FSF, S-glycosylation is more likely to occur. 7 Sglycosylation is a conjugation with less reports.…”

“…In plants, xenobiotics with hydroxyl, carboxyl, or amino groups can lose a water molecule through glycosylation to form a conjugate to increase their solubility in the cytoplasm for transport and sequestration . For example, isoproturon, an herbicide, proceeds O - and N -glycosylation in rice and wheat. , According to the reasonable reaction site of FSF, S -glycosylation is more likely to occur …”