Maize event MON810 has been genetically modified to resist certain lepidopteran insects (European corn borer: Ostrinia nubilalis).

MON810 was developed by microprojectile bombardment of embryogenic maize tissue with plasmids PVZMBK07 and PV-ZMGT10 simutaneously. However, plasmid vector PV-ZMGT10 was not integrated into the plant genome. Between the right and left borders, plasmid PVZMBK07 contained:

• The cry1Ab gene cassette. This synthetic version of the cry1Ab gene, isolated from the soil bacterium Bacillus thuringiensis (Bt) was modified to enhance the expression of the Cry1Ab protein in plants, which confers resistance to certain lepidopteran insects.

Molecular studies demonstrated that a single truncated copy of the cryIAb coding sequence was integrated into the maize genome along with the enhanced Cauliflower mosaic virus 35S promoter (P-e35S), and the hsp 70 intron (I-Hsp70). The nos terminator was not integrated into MON810 due to a truncation of the 3’ end of the gene cassette.

Western analysis confirmed that a truncated Cry1Ab protein of approximately 91 kD was inserted into the genome. Southern blot analysis indicated that the genes for glyphosate tolerance (CP4 EPSPS) and antibiotic resistance (neo) derived from PV-ZMGT10 were not transferred to event MON810 and the absence of the CP4 EPSPS and gox gene products was also confirmed by Western blotting. The CP4 EPSPS and GOX protein encoding genes were presumed to have been inserted into the initial transformant at a separate genetic loci from the cry1Ab gene and then subsequently lost through segregation during the crossing events leading to event MON810.

Southern analysis confirms that the nptII gene (originally present in PVZMBK07 and PV-ZMGT10) is not present in MON810.

Source: BCH