Silencing of HaAce1 gene by host-delivered artificial microRNA disrupts growth and development of Helicoverpa armigera

Abstract

The polyphagous insect-pest, Helicoverpa armigera, is a serious threat to a number of economically important crops. Chemical application and/or cultivation of Bt transgenic crops are the two strategies available now for insect-pest management. However, environmental pollution and long-term sustainability are major concerns against these two options. RNAi is now considered as a promising technology to complement Bt to tackle insect-pests menace. In this study, we report host-delivered silencing of HaAce1 gene, encoding the predominant isoform of H. armigera acetylcholinesterase, by an artificial microRNA, HaAce1-amiR1. Arabidopsis pre-miRNA164b was modified by replacing miR164b/miR164b* sequences with HaAce1-amiR1/HaAce1-amiR1* sequences. The recombinant HaAce1-preamiRNA1 was put under the control of CaMV 35S promoter and NOS terminator of plant binary vector pBI121, and the resultant vector cassette was used for tobacco transformation. Two transgenic tobacco lines expressing HaAce1-amiR1 was used for detached leaf insect feeding bioassays. Larval mortality of 25% and adult deformity of 20% were observed in transgenic treated insect group over that control tobacco treated insect group. The reduction in the steady-state level of HaAce1 mRNA was 70–80% in the defective adults compared to control. Our results demonstrate promise for host-delivered amiRNA-mediated silencing of HaAce1 gene for H. armigera management.

miRNA-Mediated Interactions in and between Plants and Insects

“…Given the role of miRNAs as master regulators of critical physiological processes in insects, using dsRNAi or miRNA mimics in transgenic plants to target insect genes has many potential, exciting applications in agriculture. Present day agriculture is faced with problems concerning current pest management practices, including increased pesticide resistance, environmental pollution, and toxic effects on non-target organisms, including humans [ 97 , 98 ]. In addition, insect devastations are predicted to worsen under future changing climatic conditions [ 99 ].…”

Developments and Prospects in Imperative Underexploited Vegetable Legumes Breeding: A Review

“…RNAi is a potent technology for insect resistance in legumes through silencing genes essential for insect survival. In tobacco, RNAi mediated gene silencing was achieved against Helicoverpa armigera through vector construct carrying HaAce1 gene ( H. armigera acetylcholinesterase) in the backbone of HaAce1 -preamiRNA1 from Arabidopsis controlled by CaMV 35S promoter against H.a armigera [ 167 ]. With the availability of cloned sequences of insect and pathogen genes, a similar approach can be employed in vegetable legumes for insect and pathogen resistance [ 168 ].…”

Identification and validation of potential reference gene for effective dsRNA knockdown analysis in Chilo partellus

“…Whereas insect chitinase plays crucial role in chitin digestion and in the insect gut peritrophic membrane 40 where it facilitates digestion and protects against micro-organism invasion. Silencing of both genes are documented in several insects 41–46 without any prior reference gene validation. Our result highlights the importance of reference gene normalization to avoid false discernment of target gene expression.…”