Department of Genetics and Plant Breeding, School of Agriculture, Aristotle University of Thessaloniki, P.O. Box 261, Thessaloniki GR-54124, Greece.
J Biotechnol. 2010 Oct 1;150(1):195-201. doi: 10.1016/j.jbiotec.2010.07.011. Epub 2010 Jul 16.
Plant glutathione transferases (GSTs) superfamily consists of multifunctional enzymes and forms a major part of the plants herbicide detoxification enzyme network. The tau class GST isoenzyme GmGSTU4 from soybean, exhibits catalytic activity towards the diphenyl ether herbicide fluorodifen and is active as glutathione-dependent peroxidase (GPOX). Transgenic tobacco plants of Basmas cultivar were generated via Agrobacterium transformation. The aim was to evaluate in planta, GmGSTU4's role in detoxifying the diphenyl ether herbicides fluorodifen and oxyfluorfen and the chloroacetanilides alachlor and metolachlor. Transgenic tobacco plants were verified by PCR and Southern blot hybridization and expression of GmGSTU4 was determined by RT-PCR. Leaf extracts from transgenic plants showed moderate increase in GST activity towards CDNB and a significant increase towards fluorodifen and alachlor, and at the same time an increased GPOX activity towards cumene hydroperoxide. GmGSTU4 overexpressing plants when treated with 200 μM fluorodifen or oxyfluorfen exhibited reduced relative electrolyte leakage compared to wild type plants. Moreover all GmGSTU4 overexpressing lines exhibited significantly increased tolerance towards alachlor when grown in vitro at 7.5 mg/L alachlor compared to wild type plants. No significant increased tolerance was observed to metolachlor. These results confirm the contribution of this particular GmGSTU4 isoenzyme from soybean in the detoxification of fluorodifen and alachlor, and provide the basis towards the development of transgenic plants with improved phytoremediation capabilities for future use in environmental cleanup of herbicides.
植物谷胱甘肽转移酶（GST）超家族由多功能酶组成，是植物除草剂解毒酶网络的主要组成部分。大豆中的 tau 类 GST 同工酶 GmGSTU4 对二苯醚除草剂氟草烟表现出催化活性，并且是谷胱甘肽依赖性过氧化物酶（GPOX）的活性形式。通过根癌农杆菌转化生成了 Basmas 品种的转基因烟草植物。目的是评估 GmGSTU4 在体内解毒二苯醚除草剂氟草烟和乙氧氟草醚以及氯代乙酰胺类除草剂甲草胺和异丙甲草胺中的作用。通过 PCR 和 Southern 印迹杂交验证了转基因烟草植物，并通过 RT-PCR 确定了 GmGSTU4 的表达。来自转基因植物的叶片提取物显示出对 CDNB 的 GST 活性适度增加，对氟草烟和甲草胺的显著增加，同时对 cumene hydroperoxide 的 GPOX 活性增加。与野生型植物相比，用 200 μM 氟草烟或乙氧氟草醚处理的 GmGSTU4 过表达植物表现出相对电解质泄漏减少。此外，与野生型植物相比，所有 GmGSTU4 过表达系在体外以 7.5 mg/L 甲草胺生长时对甲草胺的耐受性显著增加，而对异丙甲草胺的耐受性没有显著增加。这些结果证实了大豆中这种特定的 GmGSTU4 同工酶在氟草烟和甲草胺解毒中的作用，并为开发具有改善的植物修复能力的转基因植物提供了基础，以用于未来环境中除草剂的清理。
