First Evidence of Feeding-Induced RNAi in Banana Weevil via Exogenous Application of dsRNA
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Date
2022
Journal Title
Journal ISSN
Volume Title
Publisher
Insects
Abstract
Banana weevil (Cosmopolites sordidus) is the most devastating pest of banana and plantain
worldwide, yet current control measures are neither effective, sustainable, nor environmentally sound,
and no resistant farmer-preferred cultivars are known to date. In this paper, we examined the ability
to induce RNA interference (RNAi) in the banana weevil via feeding. We first developed an agar- and
banana corm (rhizome) flour-based artificial diet in a multi-well plate setup that allowed the banana
weevils to complete their life cycle from egg through the larval instars to the pupal stage in an average
period of 53 days. Adults emerged about 20 days later. The artificial diet allowed the tunneling and
burrowing habits of the larvae and successful metamorphosis up to adult eclosion. Adding dsRNA
for laccase2 to the artificial diet resulted in albino phenotypes, confirming gene-silencing. Finally,
C. sordidus was fed with dsRNA against a selection of essential target genes: snf7, rps13, mad1, vha-a,
vha-d, and lgl for a period of 45 days. 100% mortality within 9–16 days was realized with dssnf7,
dsrps13, and dsmad1 at 200 ng/mL artificial diet, and this corresponded to a strong reduction in
gene expression. Feeding the dsRNA targeting the two vha genes resulted in 100% mortality after
about 3–4 weeks, while treatment with dslgl resulted in no mortality above the dsgfp-control and the
water-control. Our results have implications for the development of RNAi approaches for managing
important crop pests, in that banana weevils can be controlled based on the silencing of essential
target genes as snf7, rps13, and mad1. They also highlight the need for research into the development
of RNAi for banana protection, eventually the engineering of host-induced gene-silencing (HIGS)
cultivars, given the high RNAi efficacy and its species-specific mode of action, adding the RNAi
approach to the armory of integrated pest management (IPM).
Description
Keywords
RNA interference (RNAi), Cosmopolites sordidus, Banana weevil, Artificial diet, Pest control, dsRNA feeding
Citation
Mwaka, H.S.; Christiaens, O.; Bwesigye, P.N.; Kubiriba, J.; Tushemereirwe,W.K.; Gheysen, G.; Smagghe, G. First Evidence of Feeding-Induced RNAi in BananaWeevil via Exogenous Application of dsRNA. Insects 2022, 13, 40. https://doi.org/10.3390/ insects13010040