Abstract:

To study on some sites related to glyphosate-tolerance in glyphosate N-acetyhransferase （GAT） with high glyphosate-tolerance, the high glyphosate-tolerant gatl gene and the gat2 gene nearly without glyphosate-tolerance were used to directed evolution by DNA shuffling. As a result, fourteen gatl mutants containing lower glyphosatetolerance than wild-type gatl were obtained by selection with different concentrations of glyphosate （5 mmol · L^-1 to 50 mmol · L^- 1 ）. Ten of them were single site mutated, three ones were double sites mutated, while one was three sites mutated. Among them, the glyyphosate-tolerance of mutants MTGAT3 （ H41Q ）, MTGAT5 （ S52P ）, MTGAT6 （I53M） ,MTGAT7 （F56L） ,MTGAT8 （R82G） ,MTGAT11 （I19T/P22L） and MTGAT14（Y70H/L98P/K119E） were almost lost. This research work has laid a foundation for further studying the relationship between GAT1 protein structure andd its function.

Key words: glyphosate, glyphosate N-acetyltransferase , DNA shuffling , site mutant

摘要：

为研究高抗草甘膦N-乙酰转移酶（glyphosateN—acetyhransferase，GAT）的草甘膦抗性相关位点，以高抗草甘膦的gatl基因和不具草甘膦抗性的gat2基因为出发基因，通过一轮双基因DNAshuffling，获得了抗性较野生型gatl下降的突变体14个：10个单位点突变，3个双位点突变，1个3位点突变。其中，MTGAT3（H41Q）、MTGAT5（$52P）、MTGATT6（153M）、MTGAT7（F56L）、MTGAT8（R82G）、MTGAT11（119T／1722L）和MTGAT14（Y70H／L98P／K119E）7个突变体的草甘膦抗性几乎丧失。本工作为深入研究GAT1蛋白分子结构与功能之间的关系奠定了基础。

关键词: 草甘膦 草甘膦N-乙酰转移酶 DNA shuffling 点突变