Crop Biotech Update

Novel AroA Gene from a Soil Bacterium Confers Tobacco Plant with High Glyphosate Tolerance

May 27, 2011

Glyphosate is a non-selective broad-spectrum herbicide that blocks 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS, aka AroA), a key enzyme in the biosynthesis of aromatic amino acids in plants and microorganisms. Hai-Qin Yan of Peking University in China, together with other scientists, previously isolated a glyphosate-tolerant AroA from Pseudomonas putida, a soil bacterium. This was subsequently screened in a glyphosate-sensitive Escherichia coli strain, producing a novel aRoA gene (PpaRoA1). Then they tested if the optimized gene and its expressed enzyme can provide tolerance to glyphosate in transgenic tobacco plants.

The optimized gene was introduced to tobacco plants using Agrobacterium-mediated transformation. Results of their study showed that the novel enzyme can confer tolerance to glyphosate. Furthermore, overexpression of the gene led to high glyphosate tolerance, which may imply that the novel enzyme could be used in producing new generation of glyphosate-tolerant crops.

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