RNAi in the cereal weevil Sitophilus spp: systemic gene knockdown in the bacteriome tissue.
BACKGROUND
The weevils Sitophilus spp. are among the most important cosmopolitan pests of stored cereal grains. However, their biology and physiology are poorly understood, mainly because the insect developmental stages take place within cereal grains and because of the lack of gene specific molecular manipulation.


RESULTS
To gain access to the different insect developmental stages, weevil females were allowed to lay their eggs on starch pellets and hatched embryos were collected by dissolving starch with water. Embryos were transferred between two Glass Plates filled with packed Flour (GPF) to mimic compact texture of the cereal grain, and this system allowed us to recover specific developmental stages. To knockdown the gene expressed in the bacteria-bearing organ (the bacteriome), whole larvae were injected with dsRNA to target the wpgrp1 gene and they were then left to develop for a further 4 days period. Quantitative RT-PCR and Western blot analyses on the bacteriome of these animals revealed a down-regulation of the wpgrp1 expression, both at transcript and protein levels.


CONCLUSIONS
These results demonstrate that whole larval injection with dsRNA results in a high and systemic decrease of both mRNA and protein in the bacteriome tissue. This, along with the possibility of access to the insect developmental stages, opens up a new research avenue for exploring gene specific functions in the cereal weevils.
Vallier
Agnès
A
Université de Lyon, INRA, INSA-Lyon, IFR-41, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, 20 ave A Einstein, F-69621 Villeurbanne, France. agnes.vallier@insa-lyon.fr
Vincent-Monégat
Carole
C
Laurençon
Anne
A
Heddi
Abdelaziz
A
D000818:Animals; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D017344:Genes, Insect; D007814:Larva / Q000235:genetics; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D048889:Weevils / Q000235:genetics*
D012330:RNA, Double-Stranded; D012333:RNA, Messenger