Transgenic sugarcane harboring cry1Ab and vip3Aa Bt genes for the management of Diatraea saccharalis.

The sugarcane borer (Diatraea saccharalis) is a major pest of sugarcane in the Americas, causing significant yield and quality losses. Genetic transformation using Bacillus thuringiensis (Bt) genes represents an effective strategy for integrated pest management. In this study, cry1Ab and vip3Aa genes were co-introduced into embryogenic calli of the commercial sugarcane variety TUC 03-12 using microprojectile bombardment to generate pyramided Bt events. Transgene integration was confirmed by PCR, with 247 regenerated lines testing positive for at least one transgene. Based on the total number of bombarded embryogenic calli, the overall transformation efficiency was 6.24%. Protein expression screening using lateral flow immunoassays showed that 76.6% of PCR-positive lines expressed detectable Cry1Ab protein, whereas Vip3Aa protein was detected in 33.3% of the double-positive lines. Phenotypic bioassays under controlled conditions demonstrated high larval mortality of D. saccharalis, exceeding 80% in several transgenic lines expressing both proteins. Quantification of Cry1Ab protein by ELISA revealed variability among independent lines and supported the functional relevance of protein accumulation for insect resistance. RT-qPCR analysis showed 3-140-fold and 2-1400-fold increases in cry1Ab and vip3Aa transcript levels, respectively, compared with non-transformed plants. A strong positive correlation was observed between cry1Ab transcript levels and protein accumulation, indicating that transcriptional activity is a major determinant of toxin levels. These results demonstrate that several transgenic lines exhibit enhanced resistance to D. saccharalis under controlled conditions, including lines expressing both Cry1Ab and Vip3Aa proteins. These findings support the potential of pyramided Bt sugarcane as a promising strategy for D. saccharalis management.