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Over-expression of the Gr5 aroA gene from glyphosate-contaminated soil confers high tolerance to glyphosate in tobacco

Wang, Jin, Zuo, Kaijing, Lu, Wei, Zhu, Yu, Ye, Chun, Lin, Min, Tang, Kexuan
Molecular breeding 2014 v.33 no.1 pp. 197-208
gene overexpression, genes, glyphosate, herbicide resistance, open reading frames, phylogeny, soil, tobacco, transgenic plants
Herbicide resistance is the most widely used transgenic crop trait for broad-spectrum control of weeds. Here we report a novel 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene (Gr5 ₐᵣₒA) isolated from glyphosate-contaminated soil. The full Gr5 ₐᵣₒA gene was 1,819 bp and contained a 1,341-bp open reading frame encoding a 47-kDa protein. Phylogenetic analysis showed that Gr5ₐᵣₒAis a class I EPSPS even though most such enzymes are naturally sensitive to glyphosate. Interestingly, Gr5ₐᵣₒAprotein contained highly conserved PEP and S3P binding residues (Glu-351) and several motifs insensitive to glyphosate. Transgenic Gr5 ₐᵣₒA plants (T₀) grew normally and produced seeds which we treated with a high-glyphosate solution (4× recommended spray). Analysis of the T₁progenies showed that Gr5 ₐᵣₒA was inherited at a Mendelian 3:1 segregation ratios and that glyphosate tolerance in T₁plants was unchanged. Our results show the Gr5 ₐᵣₒA gene to be a promising candidate for the development of commercial transgenic crops with high glyphosate tolerance.