Background 
Application A1281 seeks approval for the sale and use of food derived from corn line DP910521 that has been genetically modified (GM) for tolerance to the herbicide glufosinate and protection from lepidopteran insect pests. Protection against insect pests is conferred by the expression of the cry1B.34 gene, which is a chimeric gene composed of DNA sequences from the following Bacillus thuringiensis genes: (1) a cry1B-class gene; (2) the cry1Ca1 gene; and (3) the cry9Db1 gene. The encoded Cry1B.34 protein causes damage to the midgut epithelium of certain lepidopteran insect larvae, resulting in insect death. Tolerance to the herbicide glufosinate is achieved by expression of the maize-optimised mopat gene, derived from the bacterium Streptomyces viridochromogenes, encoding the enzyme phosphinothricin acetyltransferase (PAT). DP910521 also expresses the phosphomannose isomerase (PMI) protein from Escherichia coli strain K-12 as a selectable marker. The PAT and PMI proteins have been assessed previously by FSANZ, but this is the first time FSANZ has assessed the Cry1B.34 protein. This safety assessment addresses food safety and nutritional issues associated with the GM food. It therefore does not address: • risks related to the environmental release of GM plants used in food production • risks to animals that may consume feed derived from GM plants • the safety of food derived from the non-GM (conventional) plant. 

History of use 
Corn has a long history of safe use in the food supply. Corn-derived products are routinely used in a large number and diverse range of foods e.g. cornflour, starch products, breakfast cereals and high fructose corn syrup. 

Molecular characterisation 
The genes encoding Cry1B.34 (cry1B.34), PAT (mo-pat), and PMI (pmi) were introduced into corn line DP910521 via a two-step transformation process. Molecular analyses indicate that a single copy of each of the linked cry1B.34, mo-pat, and pmi cassettes is present at a single insertion site in the DP910521 genome. There are no extraneous plasmid sequences or antibiotic resistance marker genes present in this line. The introduced genetic elements were shown by molecular techniques and phenotypic analyses to be present within a single locus and stably inherited across multiple generations. 

Characterisation and safety assessment of new substances 
All three novel proteins (Cry1B.34, PAT and PMI) are expressed throughout DP910521. Expression levels are low in grain. Bioinformatic studies confirmed a lack of any significant amino acid sequence similarity between Cry1B.34 and known protein toxins or allergens. Laboratory studies demonstrated that the Cry1B.34 protein is susceptible to the action of digestive enzymes and would be thoroughly degraded before being absorbed during passage through the gastrointestinal tract. Cry1B.34 is also susceptible to heat inactivation at the high temperatures typically used in food processing. Characterisation studies confirmed that the PAT and PMI proteins were identical to proteins previously assessed by FSANZ. Updated bioinformatic analyses for the PAT and PMI proteins were consistent with previous analyses showing that neither of these proteins shared any meaningful homology with any known allergens or toxins. Taken together, the evidence supports the conclusion that Cry1B.34, PAT and PMI are not toxic or allergenic to humans. 

Herbicide metabolites 
For PAT, the metabolic profiles resulting from the protein/herbicide interaction have been established through a significant history of use. There are no concerns that the spraying of corn line DP910521 with glufosinate would result in the production of metabolites that are not also produced in non-GM crops sprayed with the same herbicide and already used in the food supply. 

Compositional analyses 
Detailed compositional analyses were performed on DP910521. Statistically significant differences were found between grain from DP910521 and the non-GM control for 4 of the 66 analytes evaluated, however these differences were small and all within the range established for existing commercial non-GM corn cultivars. Overall, the compositional data support the conclusion that there are no biologically significant differences in the levels of key constituents in grain from DP910521 compared to non-GM corn cultivars available on the market. 

Conclusion
No potential public health and safety concerns have been identified in the assessment of herbicide-tolerant and insect-protected corn line DP910521. On the basis of the data provided in the present application and other available information, food derived from DP910521 is considered to be as safe for human consumption as food derived from non-GM corn cultivars.