Persistence of double-stranded RNA in insect hemolymph as a potential determiner of RNA interference success: Evidence from Manduca sexta and Blattella germanica

Developing an in vivo toxicity assay for RNAi risk assessment in honey bees, Apis mellifera L

“…A variety of factors including nucleases in the midgut (Liu et al, 2013), salivary secretions (Allen and Walker, 2012;Christiaens et al, 2014) and haemolymph (Garbutt et al, 2013;Christiaens et al, 2014) have shown to degrade dsRNA in different insect orders and may be important in determining specificity. The results from the diet stability experiment suggest that dsRNA enzymatic barriers are most likely occurring after ingestion since no dsRNA degradation was observed from salivary secretions released in both larval and adult diet (Fig.…”

Diet-delivered RNAi in Helicoverpa armigera – Progresses and challenges

“…Reports indicate possible nuclease activity in the saliva, midgut and haemolymph of certain lepidopteran species. DNase/RNase non-specific activity distinct from that of Dicer has been reported in haemolymph of M. sexta (Garbutt et al, 2013). dsRNase activity in the digestive juices of Bombyx mori has been described (Arimatsu et al, 2007;Liu et al, 2012), with dsRNA degradation occurring within minutes of incubation with midgut juice, while greater stability was achieved for haemolymph .…”

“…Incubation with midgut juice and haemolymph of H. armigera resulted in rapid degradation of dsRNA -whether this phenomenon is due to dsRNase or Dicer activity remains unclear (Yang and Han, 2014a). It has been suggested that dsRNases developed in lepidopteran body fluids as an alternative/complementary mechanism to anti-viral defence, due to the higher susceptibility of lepidopteran species to viruses compared to other insect orders (Garbutt et al, 2013). …”

Non-Invasive Delivery of dsGST Is Lethal to the Sweet Potato Whitefly, Bemisia tabaci (G.) (Hemiptera: Aleyrodidae)

“…It is known that few factors are critical for exogenous dsRNA-mediated gene silencing in insects such as physiological importance of the target genes, concentration of cognate dsRNA, frequency of administration, and presence or absence of key core components for systemic RNAi machinery such as systemic interference defective (sid-1) and RNA-dependent RNA polymerase (RdRp), which are less understood in insects [75,76]). As far as target genes are concerned, our results showed that BtGSTs could potentially serve as a target for developing novel insect pest management strategy.…”