Jiangsu Key Laboratory of Pesticide Science, College of Sciences, Nanjing Agricultural University , Nanjing 210095, China.
State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University , Nanjing 210095, China.
Environ Sci Technol. 2017 Oct 3;51(19):11258-11268. doi: 10.1021/acs.est.7b02346. Epub 2017 Sep 20.
Atrazine (ATZ) residue in farmland is one of the environmental contaminants seriously affecting crop production and food safety. Understanding the regulatory mechanism for ATZ metabolism and degradation in plants is important to help reduce ATZ potential toxicity to both plants and human health. Here, we report our newly developed engineered rice overexpressing a novel Phase II metabolic enzyme glycosyltransfearse1 (ARGT1) responsible for transformation of ATZ residues in rice. Our results showed that transformed lines, when exposed to environmentally realistic ATZ concentration (0.2-0.8 mg/L), displayed significantly high tolerance, with 8-27% biomass and 36-56% chlorophyll content higher, but 37-69% plasma membrane injury lower than untransformed lines. Such results were well confirmed by ARGT1 expression in Arabidopsis. ARGT1-transformed rice took up 1.6-2.7 fold ATZ from its growth medium compared to its wild type (WT) and accumulated ATZ 10%-43% less than that of WT. A long-term study also showed that ATZ in the grains of ARGT1-transformed rice was reduced by 30-40% compared to WT. The ATZ-degraded products were characterized by UPLC/Q-TOF-MS/MS. More ATZ metabolites and conjugates accumulated in ARGT1-transformed rice than in WT. Eight ATZ metabolites for Phase I reaction and 10 conjugates for Phase II reaction in rice were identified, with three ATZ-glycosylated conjugates that have never been reported before. These results indicate that ARGT1 expression can facilitate uptake of ATZ from environment and metabolism in rice plants.
农田中的莠去津（ATZ）残留是严重影响作物生产和食品安全的环境污染物之一。了解 ATZ 在植物中的代谢和降解的调控机制对于帮助降低 ATZ 对植物和人类健康的潜在毒性非常重要。在这里，我们报告了我们新开发的工程水稻，该水稻过表达了一种新型的 II 相代谢酶糖基转移酶 1（ARGT1），该酶负责 ATZ 残留在水稻中的转化。我们的结果表明，转化系在暴露于环境现实浓度的 ATZ（0.2-0.8 mg/L）时，表现出明显的高耐受性，生物量增加 8-27%，叶绿素含量增加 36-56%，而质膜损伤降低 37-69%，与未转化系相比。这些结果在拟南芥中的 ARGT1 表达得到了很好的证实。与野生型（WT）相比，ARGT1 转化的水稻从其生长培养基中吸收的 ATZ 增加了 1.6-2.7 倍，积累的 ATZ 比 WT 少 10%-43%。一项长期研究还表明，与 WT 相比，ARGT1 转化水稻的谷粒中 ATZ 减少了 30-40%。利用 UPLC/Q-TOF-MS/MS 对 ATZ 降解产物进行了表征。与 WT 相比，ARGT1 转化水稻中积累了更多的 ATZ 代谢物和轭合物。在水稻中鉴定出 8 种 ATZ 代谢产物的 I 相反应和 10 种轭合物的 II 相反应，其中有 3 种 ATZ-糖基化轭合物以前从未报道过。这些结果表明，ARGT1 的表达可以促进 ATZ 在水稻中的吸收和代谢。
