Department of Agricultural Chemistry, C-3 Building, Campus of Rabanales, and Agroalimentary Excellence Campus, ceiA3, University of Córdoba, E-14071 Córdoba, Spain.
Phytochemistry. 2013 Dec;96:117-22. doi: 10.1016/j.phytochem.2013.10.008. Epub 2013 Nov 1.
The resistance to glufosinate of two lines-genetically modified (GM) and unmodified (T-590 and T-549, respectively)-of Triticum aestivum has been studied. In the GM line, the bar gene was introduced to increase the resistance to glufosinate. Experiments in a controlled growth chamber showed that line T-590 presented a high resistance to glufosinate with an ED50 value of 478.59 g active ingredient per hectare (g ai ha(-1)) versus 32.65 g ai ha(-1) for line T-549. The activity of glutamine synthetase (GS) in leaf extracts from both lines was investigated. The I50 for line T-590 was 694.10 μM glufosinate versus 55.46 μM for line T-549, with a resistance factor of 12.51. Metabolism studies showed a higher and faster penetration of glufosinate in line T-549 than in line T-590. LC-TOF/MS analysis of glufosinate metabolism at 48 h after herbicide treatment (300 g ai ha(-1)) revealed an 83.4% conversion of the herbicide (66.5% in N-acetyl-glufosinate metabolite), while in line T-549 conversion of the herbicide was about 40% (0% to N-acetyl-glufosinate). These results suggest that metabolism of glufosinate by the bar gene is a key mechanism of resistance in line T-590 that explains such high levels of herbicide tolerated by the plant, together with other mechanisms due to unmodified pathway, absorption and loss of glufosinate affinity for its target site.
研究了两种小麦（分别为转基因（GM）和非转基因（T-590 和 T-549）的抗草铵膦性。在 GM 系中，引入 bar 基因以提高对草铵膦的抗性。在可控生长室的实验表明，T-590 系对草铵膦表现出高抗性，ED50 值为 478.59 克有效成分/公顷（g ai ha(-1))，而 T-549 系为 32.65 g ai ha(-1)。研究了来自两条系的叶提取物中谷氨酰胺合成酶（GS）的活性。T-590 系的 I50 值为 694.10 μM 草铵膦，而 T-549 系为 55.46 μM，抗性系数为 12.51。代谢研究表明，草铵膦在 T-549 系中的渗透速度和渗透量均高于 T-590 系。在施药后 48 小时（300 g ai ha(-1))用 LC-TOF/MS 分析草铵膦代谢，发现除草剂的转化率为 83.4%（66.5%为 N-乙酰草铵膦代谢物），而在 T-549 系中，除草剂的转化率约为 40%（0%为 N-乙酰草铵膦）。这些结果表明，bar 基因对草铵膦的代谢是 T-590 系抗性的关键机制，解释了该系能够耐受如此高剂量的除草剂，同时还存在其他非修饰途径、吸收和降低草铵膦与靶标结合亲和力的机制。
