Production and evaluation of transgenic tobacco carrying Cry1Ab gene

Abstract

Agrobacterium-mediated transformation was performed to transfer Cry1Ab gene encoding for delta endotoxin of Bacillus thuringiensis into tobacco plant variety K326. Transgenic lines expressing Cry1Ab gene were obtained and polymerase chain reaction (PCR) analysis indicated that this gene was integrated into plant genome. Envirologix Quickstix strip test revealed the successful expression of Cry1Ab gene in transgenic tobacco plants. The morphological characteristics showed that there was no significant difference between improved lines and the control in plant height, leaf number, leaf size and stem diameter. Insecticidal activity against the leaf folder, Cnaphalocrosis medinalis (Lepidoptera: Pyralidae) was demonstrated in insect feeding bioassay. 5 days after third-instar larvae of C. medinalis fed on transgenic tobacco leaves, their body weight increased 13.93% which was much less than the control larvae fed on wild type plants. The mortality rate reached 70% was also observed. These findings suggest that Cry1Ab gene can be applied to improve resistance to C. medinalis and transgenic tobacco carrying Bt gene can be applied to tobacco plant breeding program.

Key words: Agrobacterium, Cry1Ab gene, transgenic tobacco, insect feeding bioassay