RNA silencing of hormonal biosynthetic genes impairs larval growth and development in cotton bollworm, Helicoverpa armig
- PDF / 4,659,780 Bytes
- 14 Pages / 595.276 x 790.866 pts Page_size
- 85 Downloads / 151 Views
Ó Indian Academy of Sciences (0123456789().,-volV) (0123456789().,-volV)
RNA silencing of hormonal biosynthetic genes impairs larval growth and development in cotton bollworm, Helicoverpa armigera ANJALI JAIWAL1,3, KALLEDA NATARAJASWAMY1,2 and MANCHIKATLA VENKAT RAJAM1* 1
Department of Genetics, University of Delhi – South Campus, Benito Juarez Road, New Delhi 110021, India
2
Present Address: IZKF Research Laboratory, Department of Medicine II and Pediatrics, Wuerzburg University Hospital, Wuerzburg, Germany
3
Present Address: Department of Biotechnology, Indian Institute of Madras, Chennai 600036, India *Corresponding author (Email, [email protected])
The cotton bollworm, Helicoverpa armigera, is a highly polyphagous pest, causing enormous losses to various economically important crops. The identification and in vitro functional validation of target genes of a pest is a prerequisite to combat pest via host-mediated RNA interference (RNAi). In the present study, six hormonal biosynthesis genes of H. armigera were chosen and evaluated by feeding insect larvae with dsRNAs corresponding to each target gene, viz., juvenile hormone acid methyltransferase (HaJHAMT), prothoracicotropic hormone (HaPTTH), pheromone biosynthesis-activating peptide (HaPBAP), molt regulating transcription factor (HaHR3), activated protein 4 (HaAP-4) and eclosion hormone precursor (HaEHP). The loss of function phenotypes for these hormonal genes were observed by releasing second instar larvae on to artificial diet containing target gene-specific dsRNAs. Ingestion of dsRNAs resulted in mortality ranging from 60% to 90%, reduced larval weight, phenotypic deformities and delayed pupation. The quantitative real-time PCR (qRT-PCR) analysis showed that the target gene transcript levels were decreased drastically (31% to 77%) as compared to control or unrelated control (GFP-dsRNA), and correlated well with the mortality and developmental defects of larvae. Also, a comparison of the silencing efficacy of un-diced long HaPTTH-dsRNA with RNase III diced HaPTTHdsRNA (siRNAs) revealed that long dsRNAs were more efficient in silencing the target gene. These results indicated that the hormonal biosynthesis genes have varied sensitivity towards RNAi and could be the vital targets for insect resistance in crop plants like cotton which are infested by H. armigera. Keywords. dsRNA; gene silencing; Helicoverpa armigera; hormonal biosynthesis genes; insect resistance; RNA interference
1. Introduction Helicoverpa (Heliothis) armigera (Hubner) (Lepidoptera: Noctuidae), commonly known as cotton bollworm, is a highly polyphagous and cosmopolitan
This article is part of the Topical Collection: Genetic Intervention in Plants: Mechanisms and Benefits.
agricultural pest. It causes significant losses to several agriculturally important crops, including cotton, chickpea, pigeon pea, tomato and castor (El-Wakeil 2007). In fact, it is considered to be the world’s worst pest because of its high reproductive potential and polyphagous nature. Although various conventional me
Data Loading...
