Multiple dsRNases Involved in Exogenous dsRNA Degradation of Fall Armyworm Spodoptera frugiperda

Abstract

RNAi is regarded as a promising technology for pest control. However, not all insects are sensitive to RNAi. Studies have confirmed that insect dsRNases are one of key factors affecting RNAi efficiency. In the current study, we identified four genes coding for dsRNases from the Spodoptera frugiperda genome. Spatial and temporal expression analysis showed that those dsRNases were highly expressed in the midgut and old larvae. Then a delivery method was applied for inducing efficient RNAi based on dsRNA encapsulated by liposome. Furthermore, we assessed degradation efficiency by incubation with dsRNA with gut juice or hemocoel to characterize potential roles of different SfdsRNases after suppression of SfdsRNase. The result showed that interferenced with any sfdsRNase reduced the degradation of exogenous dsRNA in midgut, interfered with sfdsRNase1 and sfdsRNase3 slowed down the degradation of exogenous dsRNA in hemolymph. Our data suggest the evolutionary expansion and multiple high activity dsRNase genes would take part in the RNAi obstinate in S. frugiperda, besides we also provide an efficient RNAi method for better use of RNAi in S. frugiperda.

RNA interference (RNAi) applications to the management of fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae): Its current trends and future prospects

“…Similarly, dsRNases clearly define why the RNAi response is limited in Spodopteran species, including S. frugiperda ( Guan et al, 2018 ; Peng et al, 2019 ; Yao et al, 2022 ). Degradation of dsRNA by dsRNases is thought to contribute to the variability in RNAi efficiency observed among insects ( Peng et al, 2019 ; Wang et al, 2019 ).…”

“…The level of dsRNases expression determines the extent of dsRNA degradation and/or RNAi efficiency in spodopteran species ( Guan et al, 2018 ; Peng et al, 2019 ). In other words, the extent of dsRNA expression can be influenced by various factors, including the types of dsRNases, insect growth stage, tissues, target genes, feed, and dsRNA delivery methods ( Peng et al, 2019 ; Yao et al, 2022 ). For instance, the level of expression of the same or different dsRNases varies across the growth stage or larval instars of Spodoptera litura , showing the variable level of dsRNases in response to the changes in the growth stage (larval instars) of insects.…”

“…Moreover, the authors recognized six genes, namely, dsRNase1, dsRNase2, EndoG, dsRNase3, dsRNase4, and dsRNase5, from S. litura . Recent studies proved that multiple dsRNases encoded by the lepidopteran genome could contribute to the lower and inconsistent RNAi efficiency in this insect group in a broad sense ( Ruo-Bing et al, 2018 ; Peng et al, 2019 ; Yao et al, 2022 ). Interestingly, Yao et al (2022) demonstrated the involvement of multiple dsRNases in exogenous dsRNA degradation in S. frugiperda larvae.…”

“…Recent studies proved that multiple dsRNases encoded by the lepidopteran genome could contribute to the lower and inconsistent RNAi efficiency in this insect group in a broad sense ( Ruo-Bing et al, 2018 ; Peng et al, 2019 ; Yao et al, 2022 ). Interestingly, Yao et al (2022) demonstrated the involvement of multiple dsRNases in exogenous dsRNA degradation in S. frugiperda larvae. This evidence provides a significant implication in the manipulation of dsRNases and/or influencing factors to reduce dsRNA degradation and increase the RNAi efficiency against S. frugiperda.…”

Silenciamento gênico de >i<Diatraea saccharalis>/i< utilizando a técnica de RNA de interferência (RNAi)

“…Essa abordagem levou a uma eficácia de RNAi significativamente aprimorada para genes essenciais em coleópteros [Tribolium castaneum (Peng et al, 2020a), Cylas puncticollis , Leptinotarsa decemlineata e Anthonomus grandis (Garcia et al, 2017)], ortópteros [Locusta migratoria Song et al, 2018) e Schistocerca gregaria ] e dípteros [Bactrocera tryoni (Tayler et al, 2019) e Drosophila suzukii (Yoon et al, 2021)]. Resultados semelhantes também foram observados em pragas sugadoras como o hemíptero Bemisia tabaci (Luo et al, 2017), e mastigadores, como os lepidópteros Ostrinia furnacalis Fan et al, 2021), O. nubilalis , Spodoptera litura (Peng et al, 2020b), Plutella xylostella (Chen et al, 2021), Spodoptera frugiperda (Yao et al, 2022) e Cnaphalocrocis medinalis .…”