Nymphal RNAi: systemic RNAi mediated gene knockdown in juvenile grasshopper.
BACKGROUND
Grasshopper serves as important model system in neuroscience, development and evolution. Representatives of this primitive insect group are also highly relevant targets of pest control efforts. Unfortunately, the lack of genetics or gene specific molecular manipulation imposes major limitations to the study of grasshopper biology.


RESULTS
We investigated whether juvenile instars of the grasshopper species Schistocerca americana are conducive to gene silencing via the systemic RNAi pathway. Injection of dsRNA corresponding to the eye colour gene vermilion into first instar nymphs triggered suppression of ommochrome formation in the eye lasting through two instars equivalent to 10-14 days in absolute time. QRT-PCR analysis revealed a two fold decrease of target transcript levels in affected animals. Control injections of EGFP dsRNA did not result in detectable phenotypic changes. RT-PCR and in situ hybridization detected ubiquitous expression of the grasshopper homolog of the dsRNA channel protein gene sid-1 in embryos, nymphs and adults.


CONCLUSIONS
Our results demonstrate that systemic dsRNA application elicits specific and long-term gene silencing in juvenile grasshopper instars. The conservation of systemic RNAi in the grasshopper suggests that this pathway can be exploited for gene specific manipulation of juvenile and adult instars in a wide range of primitive insects.
Dong
Ying
Y
Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA. ying.dong@utsouthwestern.edu
Friedrich
Markus
M
D000818:Animals; D001709:Biotechnology / Q000379:methods*; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000235:genetics; D003001:Cloning, Molecular; D005786:Gene Expression Regulation; D015723:Gene Library; D020868:Gene Silencing; D005821:Genetic Techniques; D006110:Grasshoppers / Q000235:genetics*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics; D009154:Mutation; D010641:Phenotype; D017956:Photoreceptor Cells, Invertebrate / Q000378:metabolism; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000737:chemistry; D034741:RNA, Small Interfering / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D029742:Caenorhabditis elegans Proteins; D008565:Membrane Proteins; D012330:RNA, Double-Stranded; D034741:RNA, Small Interfering; C452203:SID-1 protein, C elegans; D049452:Green Fluorescent Proteins