title: Core RNAi machinery and gene knockdown in the emerald ash borer (Agrilus planipennis).
abstract: The RNA interference (RNAi) technology has been widely used in insect functional genomics research and provides an alternative approach for insect pest management. To understand whether the emerald ash borer (Agrilus planipennis), an invasive and destructive coleopteran insect pest of ash tree (Fraxinus spp.), possesses a strong RNAi machinery that is capable of degrading target mRNA as a response to exogenous double-stranded RNA (dsRNA) induction, we identified three RNAi pathway core component genes, Dicer-2, Argonaute-2 and R2D2, from the A. planipennis genome sequence. Characterization of these core components revealed that they contain conserved domains essential for the proteins to function in the RNAi pathway. Phylogenetic analyses showed that they are closely related to homologs derived from other coleopteran species. We also delivered the dsRNA fragment of AplaScrB-2, a β-fructofuranosidase-encoding gene horizontally acquired by A. planipennis as we reported previously, into A. planipennis adults through microinjection. Quantitative real-time PCR analysis on the dsRNA-treated beetles demonstrated a significantly decreased gene expression level of AplaScrB-2 appearing on day 2 and lasting until at least day 6. This study is the first record of RNAi applied in A. planipennis.
authors.affiliation: Department of Entomology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, OH 44691, USA.
authors.forename: Chaoyang
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Department of Entomology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, OH 44691, USA.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Alvarez Gonzales
authors.affiliation: U.S. Forest Service, Northern Research Station, East Lansing, MI 48823, USA.
authors.forename: Therese M
authors.initials: TM
authors.lastname: Poland
authors.affiliation: Department of Entomology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, OH 44691, USA. Electronic address: mittapalli1@osu.edu.
authors.forename: Omprakash
authors.initials: O
authors.lastname: Mittapalli
mesh_terms: D000818:Animals; D001517:Coleoptera / Q000201:enzymology / Q000235:genetics*; D015870:Gene Expression; D055785:Gene Knockdown Techniques; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D008845:Microinjections; D010802:Phylogeny; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D043324:beta-Fructofuranosidase / Q000235:genetics
chemical_list: D019476:Insect Proteins; D012330:RNA, Double-Stranded; D012333:RNA, Messenger; D043324:beta-Fructofuranosidase
keywords: Agrilus planipennis; Argonaute-2; Dicer-2; R2D2; RNA interference; ScrB