In maize,co-expression of GAT and GR79-EPSPS provides high glyphosate resistance,along with low glyphosate residues  

作　　者：Shengyan Li Pengcheng Li Xiangyin Li Ning Wen Yinxiao Wang Wei Lu Min Lin Zhihong Lang 

机构地区：[1]Biotechnology Research Institute,Chinese Academy of Agricultural Sciences,Beijing,China [2]National Nanfan Research Institute(Sanya),Chinese Academy of Agricultural Sciences,Sanya,Hainan,China

出　　处：《aBIOTECH》2023年第4期277-290,共14页生物技术通报（英文版）

基　　金：supported by the National Transgenic Major Program of China(2016ZX08003001),。

摘　　要：Herbicide tolerance has been the dominant trait introduced during the global commercialization of genetically modified(GM)crops.Herbicide-tolerant crops,especially glyphosate-resistant crops,offer great advantages for weed management;however,despite these benefits,glyphosate-resistant maize(Zea mays L.)has not yet been commercially deployed in China.To develop a new bio-breeding resource for glyphosate-resistant maize,we introduced a codon-optimized glyphosate N-acetyltransferase gene,gat,and the enolpyruvyl-shikimate-3-phosphate synthase gene,gr79-epsps,into the maize variety B104.We selected a genetically stable high glyphosate resistance(GR)transgenic event,designated GG2,from the transgenic maize population through screening with high doses of glyphosate.A molecular analysis demonstrated that single copy of gat and gr79-epsps were integrated into the maize genome,and these two genes were stably transcribed and translated.Field trials showed that the transgenic event GG2 could tolerate 9000 g acid equivalent(a.e.)glyphosate per ha with no effect on phenotype or yield.A gas chromatography-mass spectrometry(GC–MS)analysis revealed that,shortly after glyphosate application,the glyphosate(PMG)and aminomethylphosphonic acid(AMPA)residues in GG2 leaves decreased by more than 90%compared to their levels in HGK60 transgenic plants,which only harbored the epsps gene.Additionally,PMG and its metabolic residues(AMPA and N-acetyl-PMG)were not detected in the silage or seeds of GG2,even when far more than the recommended agricultural dose of glyphosate was applied.The co-expression of gat and gr79-epsps,therefore,confers GG2 with high GR and a low risk of herbicide residue accumulation,making this germplasm a valuable GR event in herbicide-tolerant maize breeding.

关 键 词：Transgenic maize Glyphosate resistance Gr79-epsps gene Gat gene Low residues 

分 类 号：S513[农业科学—作物学]