Transformation of EPSP Synthetase Gene from Allium macrostemon Bunge into Tobacco and Improvement of Resistance in Transgenic Plants to Glyphosate

EPSPs (5-enolppyruvylshikimate-3-phosphate synthetase) is an important enzyme involved in the synthesis of the aromatic amino acids in all plants, which catalyzes phosphoenolpyruvate and shikimate 3-phophate to form 5-enolpyruvlshimimate-3-phosphate and phosphate.Glyphosate is a chemical with similar structure of phosphoenolpyruvate, which combines enzyme to inhibit the activity of EPSPs, so it is a broad spectrum herbicide to control weeds.Breeding glyphosate tolerance or resistance crops will be an effective way to control weeds.In the study, a gene cDNA (EPSPsA) isolated from Allium macrostemon Bunge was ligated with vector pWM101 to construct a recombinant vector.The recombinant gene was transformed into WS38 via Agrobacterium-mediated way to obtain transgenic tobacco seedlings.Transgenic seedlings were screened with ordinary antibiotics.PCR analysis showed that EPSPsA was successfully integrated into the tobacco genome in all the transgenic seedlings.The result of RT-PCR also validated that EPSPsA was transcripted at mRNA leve1.At 60 d after spraying 200 mg L -1 glyphosate, the transgenic tobacco plants grew better than the untransformed plants.The average fresh weight of aerial parts in transgenic plants had a significant increase compared with those in untransformed control plants.The average chlorophyll content in transgenic plants was 5.54 mg g -1 , while that in the control only 1.16 mg g -1 .In the treatment with 400 mg L -1 glyphosate, the untransformed plants died while the transgenic ones grew well in the treatment with 1 000 mg L -1 glyphosate.These results proved that the EP-SPsA can improve the glyphosate tolerance in tobacco.