title: Transgenic plants over-expressing insect-specific microRNA acquire insecticidal activity against Helicoverpa armigera: an alternative to Bt-toxin technology.
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.
authors.affiliation: International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067, India.
authors.forename: Aditi
authors.initials: A
authors.lastname: Agrawal
authors.affiliation: International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067, India.
authors.forename: Vijayalakshmi
authors.initials: V
authors.lastname: Rajamani
authors.affiliation: International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067, India.
authors.forename: Vanga Siva
authors.initials: VS
authors.lastname: Reddy
authors.affiliation: Department of Genetics, University of Delhi, New Delhi, 110021, India.
authors.forename: Sunil Kumar
authors.initials: SK
authors.lastname: Mukherjee
authors.affiliation: International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067, India. raj@icgeb.res.in.
authors.forename: Raj K
authors.initials: RK
authors.lastname: Bhatnagar
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000378:metabolism; D001427:Bacterial Toxins / Q000494:pharmacology; D007313:Insecta / Q000254:growth & development / Q000472:pathogenicity*; D007814:Larva / Q000472:pathogenicity*; D035683:MicroRNAs / Q000235:genetics*; D009036:Moths / Q000472:pathogenicity*; D010572:Pest Control, Biological; D030821:Plants, Genetically Modified / Q000235:genetics*; D014026:Nicotiana / Q000235:genetics
chemical_list: D001427:Bacterial Toxins; D035683:MicroRNAs
keywords: Agrobacterium; Artificial miRNA; Insect bioassay; Insecticidal; Transgenic tobacco