Inheritance and expression of Bt cry1Ba3 gene in progeny from transformed cabbage plants

Stable inheritance and expression of transgene are important parameters for successful use of a transgenic crop. We previously transformed a Bt cry1Ba3 gene into cabbage inbred line CA21-3. To evaluate the stability of our Bt cabbage lineages, transgene inheritance and expression were examined in four successive generations under greenhouse conditions. In our study, T₁, T₂ and T₃ progenies of the three independent transgenic lineages (YA-1, YA-2 and YA-3) were generated and then the inheritance and expression of cry1Ba3 were analyzed in sexually derived progeny. Segregation ratio of 2.81:1, 3.27:1 and 3.07:1 was found in T₁ progeny of lineages YA-1, YA-2 and YA-3, respectively. Chi-square analysis indicated that these segregation ratios of corresponding population fit the 3:1 ratio. Segregation ratios of the transgene in T₂ progeny showed either 3:1 or all expression of cry1Ba3. These data suggest that cry1Ba3 in CA21-3 can be inherited in a Mendelian manner. ELISA analysis of transgenic plants from four generations demonstrated that cry1Ba3 had been stably transmitted to the T₃ progeny. Additionally, under artificial infestation conditions, the homozygous T₃-YA-1-2-1 line exhibited excellent resistance to Plutella xylostella as compared with un-transformed CA21-3. All these results imply that the three cabbage lineages are genetically stable and can be used to inhibit damage on cabbage caused by P. xylostella.