Abstract
The success of Bt transgenics in controlling predation of crops has been tempered by sporadic emergence of resistance in targeted insect larvae. Such emerging threats have prompted the search for novel insecticidal molecules that are specific and could be expressed through plants. We have resorted to small RNA-based technology for an investigative search and focused our attention to an insect-specific miRNA that interferes with the insect molting process resulting in the death of the larvae. In this study, we report the designing of a vector that produces artificial microRNA (amiR), namely amiR-24, which targets the chitinase gene of Helicoverpa armigera. This vector was used as transgene in tobacco. Northern blot and real-time analysis revealed the high level expression of amiR-24 in transgenic tobacco plants. Larvae feeding on the transgenic plants ceased to molt further and eventually died. Our results demonstrate that transgenic tobacco plants can express amiR-24 insectice specific to H. armigera.
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Acknowledgments
We acknowledge the financial support from National Agriculture Innovation project (NAIP) of ICAR (Indian Council for Agricultural Research), India (Grant No. RNAi-2012). We acknowledge the assistance of Dr. Anil Sharma during the statistical analysis. We sincerely thank Tara Ram for technical assistance during rearing of H. armigera larvae.
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Supplemental Fig. 1
Insect bioassays of transgenic tobacco plants with (a) wild type plant (b) amiR-24C construct (c) amiR-24 construct (TIFF 2377 kb)
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Agrawal, A., Rajamani, V., Reddy, V.S. et al. Transgenic plants over-expressing insect-specific microRNA acquire insecticidal activity against Helicoverpa armigera: an alternative to Bt-toxin technology. Transgenic Res 24, 791–801 (2015). https://doi.org/10.1007/s11248-015-9880-x
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DOI: https://doi.org/10.1007/s11248-015-9880-x