title: Establishing an in vivo assay system to identify components involved in environmental RNA interference in the western corn rootworm.
abstract: The discovery of environmental RNA interference (RNAi), in which gene expression is suppressed via feeding with double-stranded RNA (dsRNA) molecules, opened the door to the practical application of RNAi-based techniques in crop pest management. The western corn rootworm (WCR, Diabrotica virgifera virgifera) is one of the most devastating corn pests in North America. Interestingly, WCR displays a robust environmental RNAi response, raising the possibility of applying an RNAi-based pest management strategy to this pest. Understanding the molecular mechanisms involved in the WCR environmental RNAi process will allow for determining the rate limiting steps involved with dsRNA toxicity and potential dsRNA resistance mechanisms in WCR. In this study, we have established a two-step in vivo assay system, which allows us to evaluate the involvement of genes in environmental RNAi in WCR. We show that laccase 2 and ebony, critical cuticle pigmentation/tanning genes, can be used as marker genes in our assay system, with ebony being a more stable marker to monitor RNAi activity. In addition, we optimized the dsRNA dose and length for the assay, and confirmed that this assay system is sensitive to detect well-known RNAi components such as Dicer-2 and Argonaute-2. We also evaluated two WCR sid1- like (sil) genes with this assay system. This system will be useful to quickly survey candidate systemic RNAi genes in WCR, and also will be adaptable for a genome-wide RNAi screening to give us an unbiased view of the environmental/systemic RNAi pathway in WCR.
authors.affiliation: Department of Biology, Miami University, Oxford, Ohio, United States of America.
authors.forename: Keita
authors.initials: K
authors.lastname: Miyata
authors.affiliation: Biotechnology Division, Monsanto Company, Chesterfield, Missouri, United States of America.
authors.forename: Parthasarathy
authors.initials: P
authors.lastname: Ramaseshadri
authors.affiliation: Biotechnology Division, Monsanto Company, Chesterfield, Missouri, United States of America.
authors.forename: Yuanji
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Biotechnology Division, Monsanto Company, Chesterfield, Missouri, United States of America.
authors.forename: Gerrit
authors.initials: G
authors.lastname: Segers
authors.affiliation: Biotechnology Division, Monsanto Company, Chesterfield, Missouri, United States of America.
authors.forename: Renata
authors.initials: R
authors.lastname: Bolognesi
authors.affiliation: Department of Biology, Miami University, Oxford, Ohio, United States of America.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Tomoyasu
mesh_terms: D000818:Animals; D001517:Coleoptera / Q000235:genetics* / Q000254:growth & development; D018628:Gene Dosage; D017344:Genes, Insect; D007300:Insect Control / Q000379:methods; D008018:Life Cycle Stages / Q000235:genetics; D010572:Pest Control, Biological / Q000379:methods; D010641:Phenotype; D034622:RNA Interference; D012330:RNA, Double-Stranded; D015203:Reproducibility of Results
chemical_list: D012330:RNA, Double-Stranded