Variability in expression of insecticidal Cry1Ab gene in Indica Basmati rice

Abstract

The expression of an insecticidal gene cry1Ab, under three differentpromoters was studied in leaves, stem and panicles to determineorgan-specificity in Basmati rice. Enhanced resistance against twoLepidopteran insects, stem bore (Scripophaga incertulas) and leaffolder (Cnaphalocrocis medinalis) was observed. The result of westernhybridization and insect bioassays demonstrated that all these promotersexpress the cry1Ab gene at similar levels in leaves and panicles. Thecry1Ab gene was expressed in stems at 0.05% of the total protein underthe control of the PEPC promoter alone or in combination with thepollen-specific promoter. On the other hand it was expressed at 0.15%under the control of the ubiquitin promoter. Southern blot hybridization ofthese plants indicated integration of the complete plant transcriptional unitat multiple insertion sites. These results demonstrated that a specificpromoter could be used to limit the expression of cry1Ab gene in thedesired parts of Basmati rice plants.