Development of AtMYB12-expressing transgenic tobacco callus culture for production of rutin with biopesticidal potential

Flavonoids synthesized by the phenylpropanoid pathway participate in a number of physiological and biochemical processes in plants. Flavonols, among flavonoids, are considered as health-protective components in functional foods and they protect plants against certain insect pests. There have been efforts to develop strategies for the enhanced production of flavonols in plants, but limited success was achieved due to complex regulation and poor substrate availability. In the present study, we have developed and optimized method for callus cultures for transgenic tobacco line expressing a flavonol-specific transcription factor, AtMYB12, with an objective to use callus as an alternative source of rutin. Transgenic callus displayed enhanced expression of genes related to biosynthetic pathway leading to increased accumulation of flavonols, especially rutin. At each time point of callus growth, the rutin content of transgenic callus was several folds higher than that of wild-type tobacco callus. Supplementation of semi-synthetic diet with extract from transgenic callus as well as purified rutin led to mortality and growth reduction in the Spodoptera litura and Helicoverpa armigera larvae. This study suggests the biotechnological potential of AtMYB12-expressing callus cultures for the production of rutin, which can be used for biopesticide formulations against insect pests. Tobacco callus cultures expressing AtMYB12 accumulate enhanced content of rutin and can be used as a potential alternative source of rutin as well as biopesticides against insect pests.