Maize Bt176 is resistant to lepidopteran species, in particular to the European corn borer (Ostrinia nubilalis).
Bt176 was produced by biolistic co-transformation with the plasmids pCIB3064 and pCIB4431 into the proprietary inbreed line CG00526.
Resistance to lepidopteran species is conferred by expression of CS-cry1Ab-BACTU from Bacillus thuringiensis subsp. kurstaki strain HD1.
Bt176 also expresses CS-bar-STRHY from the bacterium Streptomyces hygroscopicus which confers increased tolerance to the herbicide phosphinothricin (glufosinate). However, CS-bar-STRHY was only used as a selectable marker for successful plant transformation and the level of expression is insufficient to confer tolerance to commercial applications of phosphinothricin.
No information could be found on whether vector backbone sequences were integrated into the maize genome.
Southern blot analyses indicated the integration of possibly six copies of the cry gene and at least two copies of the bar gene.
Backcrossing experiments revealed a 1:1 phenotypic segregation ratio for phosphinothricin tolerance and lepidopteran resistance indicating a single insertion site of the recombinant constructs. This result could be corroborated by Restriction Fragment Length Polymorphism (RFLP) and it was shown that the recombinant constructs integrated on Chromosome 1 of maize.