Peñaloza-Vazquez A, Mena G L, Herrera-Estrella L, Bailey A M
Departamento de Ingeniería Genética de Plantas CINVESTAV-IPN Unidad Irapuato, Mexico.
Appl Environ Microbiol. 1995 Feb;61(2):538-43. doi: 10.1128/aem.61.2.538-543.1995.
Thirty-four strains of Pseudomonas pseudomallei isolated from soil were selected for their ability to degrade the phosphonate herbicide glyphosate. All strains tested were able to grow on glyphosate as the only phosphorus source without the addition of aromatic amino acids. One of these strains, P. pseudomallei 22, showed 50% glyphosate degradation in 40 h in glyphosate medium. From a genomic library of this strain constructed in pUC19, we have isolated a plasmid carrying a 3.0-kb DNA fragment which confers to E. coli the ability to use glyphosate as a phosphorus source. This 3.0-kb DNA fragment from P. pseudomallei contained two open reading frames (glpA and glpB) which are involved in glyphosate tolerance and in the modification of glyphosate to a substrate of the Escherichia coli carbon-phosphorus lyase. glpA exhibited significant homology with the E. coli hygromycin phosphotransferase gene. It was also found that the hygromycin phosphotransferase genes from both P. pseudomallei and E. coli confer tolerance to glyphosate.
从土壤中分离出34株假鼻疽假单胞菌，根据它们降解膦酸酯除草剂草甘膦的能力进行筛选。所有测试菌株在不添加芳香族氨基酸的情况下，都能够以草甘膦作为唯一的磷源生长。其中一株菌株，假鼻疽假单胞菌22，在草甘膦培养基中40小时内可降解50%的草甘膦。从该菌株构建于pUC19的基因组文库中，我们分离出一个携带3.0 kb DNA片段的质粒，该片段赋予大肠杆菌利用草甘膦作为磷源的能力。来自假鼻疽假单胞菌的这个3.0 kb DNA片段包含两个开放阅读框（glpA和glpB），它们参与草甘膦耐受性以及将草甘膦修饰为大肠杆菌碳-磷裂解酶的底物。glpA与大肠杆菌潮霉素磷酸转移酶基因具有显著同源性。还发现来自假鼻疽假单胞菌和大肠杆菌的潮霉素磷酸转移酶基因都赋予对草甘膦的耐受性。
