RNAi‐mediated knockdown of a <i>Spodoptera frugiperda</i> trypsin‐like serine‐protease gene reduces susceptibility to a <i>Bacillus thuringiensis</i> Cry1Ca1 protoxin

Rodríguez-Cabrera, Lianet; Trujillo-Bacallao, Damian; Borrás‐Hidalgo, Orlando; Wright, Denis J.; Ayra‐Pardo, Camilo

doi:10.1111/j.1462-2920.2010.02259.x

Cited by 66 publications

(41 citation statements)

References 49 publications

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“…11). Similar results were also found in the study of Rodriguez-Cabrera et al [58], which showed the RNAi of a trypsin-like serine-protease gene reduced the susceptibility of Spodoptera frugiperda to a Bacillus thuringiensis protoxin. In Manduca sexta , serpins have been proven to inhibit the PO activity in a dose-dependent manner [19], [59], however, in our findings, RNAi-mediated knockdown of serpins significantly increased the total PO activity measured by using dopamine as a substrate in the larvae of P. xylostella (Fig.…”

Section: Discussionsupporting

confidence: 89%

RNAi-Mediated Knockdown of Serine Protease Inhibitor Genes Increases the Mortality of Plutella xylostella Challenged by Destruxin A

et al. 2014

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Destruxin A is a mycotoxin that is secreted by entomopathogenic fungi which has a broad-spectrum insecticidal effect. Previous transcript and protein profiling analysis showed that destruxin A has significant effects on the expression of serine protease inhibitor genes (serpin-2, 4, 5) in the larvae of Plutella xylostella. In the current study, we aimed to understand the role of serpins under application of destruxin A. We obtained two full-length cDNA sequences of P. xylostella serpins, named serpin-4 and serpin-5, and cloned the serpin-2 gene whose full-length has already been published. Phylogenetic analysis indicated that these two serpin genes were highly clustered with other serpins associated with the immune response in other insects. The temporal and spatial expression of serpin-2, serpin-4 and serpin-5 were determined to be the highest in the fat body and hemolymph of 4th larval stage using qRT-PCR and western blot detection techniques. RNA interference (RNAi) mediated knockdown of P. xylostella serpin genes was carried out by microinjection of double-stranded RNA (dsRNA). The expression levels of serpins decreased significantly after RNAi. Results showed that the depletion of serpins induced cecropins expression, increased phenoloxidase (PO) activity, body melanization and mortality in the larvae of P. xylostella under the same lethal concentration of destruxin A. The superimposed effects of serpins RNAi were similar with the destruxin A treatment upon mortality of P. xylostella larvae. We discovered for the first time that serpins play indispensable role in P. xylostella when challenged by destruxin A and deduced the possible function mechanism of destruxin A. Our findings are conducive to fully understanding the potential insecticidal mechanism of destruxin A and constitute a well-defined potential molecular target for novel insecticides.

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Section: Discussionsupporting

confidence: 89%

RNAi-Mediated Knockdown of Serine Protease Inhibitor Genes Increases the Mortality of Plutella xylostella Challenged by Destruxin A

et al. 2014

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“…Reflecting the response of other beetles, successful control of WCR via knockdown of important genes by transgenic crops expressing dsRNAs was reported ten years ago [6]. In contrast, successful expression knockdown of a FAW gene target via laboratory dsRNA feeding has only been reported twice [45, 46], and has not been reported for SGSB. Differences between characteristics of the core RNAi machinery have not been extensively explored as a potential contributor to the observed responses in these species.…”

Section: Discussionmentioning

confidence: 99%

Identification and comparison of key RNA interference machinery from western corn rootworm, fall armyworm, and southern green stink bug

et al. 2018

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RNA interference (RNAi)-based technology shows great potential for use in agriculture, particularly for management of costly insect pests. In the decade since the insecticidal effects of environmentally-introduced RNA were first reported, this treatment has been applied to several types of insect pests. Through the course of those efforts, it has become apparent that different insects exhibit a range of sensitivity to environmentally-introduced RNAs. The variation in responses across insect is not well-understood, with differences in the underlying RNAi mechanisms being one explanation. This study evaluates eight proteins among three agricultural pests whose responses to environmental RNAi are known to differ: western corn rootworm (Diabrotica virgifera virgifera), fall armyworm (Spodoptera frugiperda), and southern green stink bug (Nezara viridula). These proteins have been identified in various organisms as centrally involved in facilitating the microRNA- and small interfering-RNA-mediated interference responses. Various bioinformatics tools, as well as gene expression profiling, were used to identify and evaluate putative homologues for characteristics that may contribute to the differing responses of these insects, such as the absence of critical functional domains within expressed sequences, the absence of entire gene sequences, or unusually low or undetectable expression of critical genes. Though many similarities were observed, the number of isoforms and expression levels of double-stranded RNA-binding and argonaute proteins varied across insect. Differences among key RNAi machinery genes of these three pests may impact the function of their RNAi pathways, and therefore, their respective responses to exogenous RNAs.

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“…In lepidopterans, analysis of proteinase activities from gut extracts have shown the lack of trypsin-like and of chymotrypsin-like activity in Bt-resistant strains [20]. Furthermore, the role of proteases in resistance to Bt toxin Cry1Ca1 was demonstrated in the caterpillar Spodoptera frugiperda where a serine-protease gene under-transcribed in the midgut of intoxicated larvae was further shown by RNAi-mediated knockdown to be involved in both reduced protoxin activation in the midgut and reduced susceptibility of caterpillars to toxins in bioassays [24]. …”

Section: Discussionmentioning

confidence: 99%

Gene expression patterns and sequence polymorphisms associated with mosquito resistance to Bacillus thuringiensis israelensis toxins

et al. 2014

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BackgroundDespite the intensive use of Bacillus thuringiensis israelensis (Bti) toxins for mosquito control, little is known about the long term effect of exposure to this cocktail of toxins on target mosquito populations. In contrast to the many cases of resistance to Bacillus thuringiensis Cry toxins observed in other insects, there is no evidence so far for Bti resistance evolution in field mosquito populations. High fitness costs measured in a Bti selected mosquito laboratory strain suggest that evolving resistance to Bti is costly. The aim of the present study was to identify transcription level and polymorphism variations associated with resistance to Bti toxins in the dengue vector Aedes aegypti. We used RNA sequencing (RNA-seq) for comparing a laboratory-selected strain showing elevated resistance to Bti toxins and its parental non-selected susceptible strain. As the resistant strain displayed two marked larval development phenotypes (slow and normal), each phenotype was analyzed separately in order to evidence potential links between resistance mechanisms and mosquito life-history traits.ResultsA total of 12,458 genes were detected of which 844 were differentially transcribed between the resistant and susceptible strains. Polymorphism analysis revealed a total of 68,541 SNPs of which 12,571 SNPs exhibited more than 40% frequency difference between the resistant and susceptible strains, affecting 2,953 genes. Bti resistance is associated with changes in the transcription level of enzymes involved in detoxification and chitin metabolism. Among previously described Bti-toxin receptors, four alkaline phosphatases (ALPs) were differentially transcribed between resistant and susceptible larvae, and non-synonymous changes affected the protein sequence of one cadherin, six aminopeptidases (APNs) and four α-amylases. Other putative Cry receptors located in lipid rafts, such as flotillin and glycoside hydrolases, were under-transcribed and/or contained non-synonymous substitutions. Finally, immunity-related genes showed contrasted transcription and polymorphisms patterns between the two developmental resistant phenotypes, suggesting the existence of trade-offs between Bti-resistance, life-history traits and immunity.ConclusionsThe present study is the first to analyze the whole transcriptome of Bti-resistant mosquitoes by RNA-seq, shedding light on the importance of studying both transcription levels and sequence polymorphism variations to get a comprehensive view of insecticide resistance.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-926) contains supplementary material, which is available to authorized users.

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RNAi‐mediated knockdown of a Spodoptera frugiperda trypsin‐like serine‐protease gene reduces susceptibility to a Bacillus thuringiensis Cry1Ca1 protoxin

Cited by 66 publications

References 49 publications

RNAi-Mediated Knockdown of Serine Protease Inhibitor Genes Increases the Mortality of Plutella xylostella Challenged by Destruxin A

RNAi-Mediated Knockdown of Serine Protease Inhibitor Genes Increases the Mortality of Plutella xylostella Challenged by Destruxin A

Identification and comparison of key RNA interference machinery from western corn rootworm, fall armyworm, and southern green stink bug

Gene expression patterns and sequence polymorphisms associated with mosquito resistance to Bacillus thuringiensis israelensis toxins

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