RNAi-mediated gene silencing in Rhynchophorus ferrugineus (Oliver) (Coleoptera: Curculionidae)

Abstract

RNA interference (RNAi) is a powerful strategy for gene function analysis, and it is also widely studied in view of a promising use in pest control. The red palm weevil, Rhynchophorus ferrugineus (Oliver) (Coleoptera: Curculionidae), is one of the most devastating pests of palm in the world. Conventional pest management practices are not adequate to control this insect, thus the development of efficient approaches with minimal environmental impact are needed. In this work, the potential of RNAi in R. ferrugineus has been investigated through the silencing of three different genes (alpha-amylase, V-ATPase, Ecdysone receptor). For each gene we tested two different doses (1,500 and 5,500 ng) and two delivery techniques (injection and ingestion), evaluating both gene knockdown and mortality on insects. Results show that RNAi mediated gene silencing in R. ferrugineus varies from gene to gene, and that the response is dose-dependent, with stronger effects when dsRNA was administered by injection. In parallel, the same study was carried out with the model organism Tribolium castaneum Herbst (Coleoptera: Tenebrionidae), with results showing a different pattern of response, although the two insects belong to the same order

Delivery of gene‐specific dsRNA by microinjection and feeding induces RNAi response in Sri Lanka weevil, Myllocerus undecimpustulatus undatus Marshall

“…11,49,50 The level of sensitivity to RNAi by microinjection and oral exposure can be variable among insects within the same order. For example, in the Coleoptera order, D. virgifera virgifera, T. castaneum, Leptinotarsa decemlineata, Meligethes aeneus, Rhynchophorus ferrugineus, C. puncticollis, C. brunneus and A. planipennis are sensitive to both methods of dsRNA delivery, 29,30,49,[51][52][53][54][55] whereas Anthonomus grandis, Anthonomus eugenii and Aethina tumida are recalcitrant to RNAi by oral exposure. [56][57][58] These studies demonstrate the importance of evaluating the RNAi sensitivity by microinjection as well as by feeding in the target insect species since it is not possible to predict the RNAi effectiveness based on the RNAi response found in other insects, even in closely related species.…”

Pectin Digestion in Herbivorous Beetles: Impact of Pseudoenzymes Exceeds That of Their Active Counterparts

“…In plants, starch is the main storage polysaccharide and the major source of carbohydrate-based energy in herbivorous insects. Fitness costs, such as developmental delay resulting from altered starch digestion in insects either through the ingestion of plant α-amylase inhibitors or the knockdown of amylase genes, illustrate the importance of carbohydrate accessibility (Pueyo et al, 1995; Borzoui et al, 2017; Laudani et al, 2017).…”

Pectin digestion in herbivorous beetles: Impact of pseudoenzymes exceeds that of their active counterparts

“…In plants, starch is the main storage polysaccharide and the major source of carbohydrate-based energy in herbivorous insects. Fitness costs, such as developmental delay resulting from altered starch digestion in insects either through the ingestion of plant α-amylase inhibitors or the knockdown of amylase genes, illustrate the importance of carbohydrate accessibility [49][50][51]. There is another potential carbohydrate source that is omnipresent in a herbivore´s diet but often overlooked: the plant cell wall (PCW).…”