<p style="text-align: justify;">Maize line MON809 was produced by biolistic transformation of embryogenic maize cells with a mixture of DNA from two plasmids, PV-ZMBK07 and PV-ZMGT10. Plasmid PV-ZMBK07 contained the synthetic <i>cr1Ab</i> gene regulated by the enhanced duplicated cauliflower mosaic virus 35S promoter (CaMV E35S) and the maize hsp70 heat shock protein intron. The polyadenylation signal was from the <i>Agrobacterium tumefaciens</i> nopaline synthase (<i>nos</i>) gene. Plasmid PV-ZMBK07 also contained sequences from <i>lac</i>Z operon (a partial <i>E. coli</i> <i>lac</i>I coding sequence, the promoter <i>plac</i> and a partial coding sequence for beta-galactosidase from pUC119), ori-pUC (replication origin for pUC plasmids), and the <i>neo</i> gene, which encodes neomycin phosphotransferase II (NPT II) that imparts resistance to the antibiotic kanamycin. The second plasmid, PV-AMGT10, contained genes encoding the CP4 EPSPS enzyme from the common soil bacterium, <i>A. tumefaciens</i> sp. CP4, and glyphosate oxidoreductase (<i>goxv247</i>) from <i>Ochrobactrum anthropi</i>. The expression of these genes was used as a selectable marker to identify transformed plants on medium containing glyphosate but was not sufficient to provide field level tolerance to glyphosate containing herbicides. Constitutive expression of these genes in plant cells was under the control of the CaMV E35S promoter, the hsp70 intron, and <i>nos</i> 3&#39; terminator. Post-translational targeting of the CP4 EPSPS and glyphosate oxidoreductase enzymes to the chloroplast was accomplished by fusion of the 5&#39;-terminal coding sequences with the chloroplast transit peptide DNA sequences from the <i>Arabidopsis thaliana</i> EPSPS gene (CTP2) and from <i>A. thaliana</i> SSU1A gene (CTP1), respectively. Plasmid PV-ZMGT10 also contained sequences from the <i>lac</i>Z operon, ori-pUC and the <i>neo</i> gene. The <i>neo</i> gene on both plasmids was included as a selectable marker to identify bacteria transformed with recombinant plasmid DNAs. Expression of the <i>neo</i> gene was regulated by a bacterial promoter and therefore is not functional in plants.</p>
