Development of an RNA interference tool, characterization of its target, and an ecological test of caste differentiation in the eusocial wasp polistes

• Published in: PloS one Vol. 6; no. 11; p. e26641
• Main Authors: Hunt, James H, Mutti, Navdeep S, Havukainen, Heli, Henshaw, Michael T, Amdam, Gro V
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.11.2011; Public Library of Science (PLoS)
• Subjects: Amino Acid Sequence; Animal behavior; Animals; Apis mellifera; Base Sequence; Behavioral biology; Biochemistry; Biological Evolution; Biology; Caste differentiation; Castes; Colonies; Data acquisition; Deglycosylation; Double-stranded RNA; Ecological research; Ecology; Evolution; Females; Field tests; Food science; Gene expression; Gene silencing; Genetic engineering; Genomics; Glycosylation; Hemolymph; Honey; Hymenoptera; Insect Proteins - antagonists & inhibitors; Insect Proteins - genetics; Insects; Interference; Laboratories; Larva - genetics; Larva - growth & development; Larvae; Larval development; Life sciences; Molecular Sequence Data; Ovaries; Phenotype; Phosphorylation; Physics; Physiology; Polistes; Proteins; Proteomics; Ribonucleic acid; RNA; RNA Interference; RNA, Double-Stranded - genetics; RNA-mediated interference; Social Dominance; Solenopsis invicta; Spectrometry, Mass, Electrospray Ionization; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Storage; Storage proteins; Studies; Tribolium; Vespidae; Wasps; Wasps - genetics; Norway; United States > US; Arizona
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0026641

Recent advancements in genomics provide new tools for evolutionary ecological research. The paper wasp genus Polistes is a model for social insect evolution and behavioral ecology. We developed RNA interference (RNAi)-mediated gene silencing to explore proposed connections between expression of hexameric storage proteins and worker vs. gyne (potential future foundress) castes in naturally-founded colonies of P. metricus. We extended four fragments of putative hexamerin-encoding P. metricus transcripts acquired from a previous study and fully sequenced a gene that encodes Hexamerin 2, one of two proposed hexameric storage proteins of P. metricus. MALDI-TOF/TOF, LC-MSMS, deglycosylation, and detection of phosphorylation assays showed that the two putative hexamerins diverge in peptide sequence and biochemistry. We targeted the hexamerin 2 gene in 5(th) (last)-instar larvae by feeding RNAi-inducing double-stranded hexamerin 2 RNA directly to larvae in naturally-founded colonies in the field. Larval development and adult traits were not significantly altered in hexamerin 2 knockdowns, but there were suggestive trends toward increased developmental time and less developed ovaries, which are gyne characteristics. By demonstrating how data acquisition from 454/Roche pyrosequencing can be combined with biochemical and proteomics assays and how RNAi can be deployed successfully in field experiments on Polistes, our results pave the way for functional genomic research that can contribute significantly to learning the interactions of environment, development, and the roles they play in paper wasp evolution and behavioral ecology.