Gene silencing of two acetylcholinesterases reveals their cholinergic and non‐cholinergic functions in Rhopalosiphum padi and Sitobion avenae

BACKGROUD The function of acetylcholinesterase ( AChE ) is to terminate synaptic transmission by hydrolysing the neurotransmitter acetylcholine ( ACh ) in the synaptic cleft, and thus it is an effective target for organophosphate ( OP ) and carbamate ( CB ) insecticides. RESULTS The transcript levels of the four Ace genes were dramatically suppressed by injection of their respective dsRNA in Rhopalosiphum padi and Sitobion avenae . However, the AChE activity changes in the Ace1 knockdown aphids were consistent with the significant transcript level changes of Ace1 genes in these aphids, but not for Ace2 . Bioassay results indicated that the suppression of RpAce1 increased its susceptibilities to pirimicarb and malathion, and SaAce1 silencing also increased susceptibility to pirimicarb in S. avenae , whereas the knockdowns of RpAce2 and SaAce2 had a slight effect on their susceptibilities. The knockdown of Ace1 genes also caused significant reductions in fecundity in the aphids of their parental generation. CONCLUSIONS These results suggest that AChE1 is a predominant cholinergic enzyme and is the target of anticholinesterase insecticides in both R. padi and S. avenae . It also plays a non‐cholinergic role in fecundity of these aphids. AChE2 may also be important for the toxicological function, although its importance appeared to be lower than that of AChE1 . © 2014 Society of Chemical Industry