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Prof. Kun Yan Zhu
Kansas State University

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0 RNA interference
0 Insecticide resistance
0 insect toxicology
0 chitin biosynthesis
0 chitin metabolism

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RNA interference
Insecticide resistance
chitin biosynthesis
chitin metabolism
insect toxicology

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Original article
Published: 04 August 2021 in Insect Science
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Rab proteins constitute the largest family of small GTPases, which play pivotal roles in intracellular membrane trafficking in all eukaryotes. A number of Rab genes have been identified in eukaryotes; however, very little information about these genes has been reported in insects. In the current study, for the first time we identified and characterized 27 Rab family genes from Locusta migratoria. Phylogenetic analysis and comparison of domain architecture indicated that Rab family genes are highly conserved among insect species. Tissue-dependent expression profiles indicated that expression of Rab genes was highest in the ovary, except for LmRab3, which was most highly expressed in hemolymph. The biological function of each Rab gene was investigated using RNA interference (RNAi). Double-stranded RNA targeting each Rab gene was injected into the hemocoel of nymphs and revealed that suppression of two Rab genes (LmRab5 and LmRab11A) caused 100% mortality. In addition, nymphs injected with dsLmRab5 exhibited severe phenotypic defects in the gastric caeca and midgut, while dsLmRab11A arrested the molting process. We then applied the RNAi of RNAi technique to test if silencing either of these two genes would affect the suppression of the lethal giant larvae (LmLgl) reporter gene and found that suppression of LmRab5 diminished the RNAi efficiency of LmLgl, whereas suppression of LmRab11A enhanced RNAi efficiency of LmLgl. These results indicate that Rab genes contribute differently to RNAi efficiency in different tissues. Our study provides a foundation for further functional investigations of Rab genes and their contributions to RNAi efficiency in L. migratoria.

ACS Style

Mureed Abbas; Yun‐He Fan; Xue‐Kai Shi; Lu Gao; Yan‐Li Wang; Tao Li; Anastasia M.W. Cooper; Kristopher Silver; Kun Yan Zhu; Jian‐Zhen Zhang. Identification of Rab family genes and functional analyses of LmRab5 and LmRab11A in the development and RNA interference of Locusta migratoria. Insect Science 2021, 1 .

AMA Style

Mureed Abbas, Yun‐He Fan, Xue‐Kai Shi, Lu Gao, Yan‐Li Wang, Tao Li, Anastasia M.W. Cooper, Kristopher Silver, Kun Yan Zhu, Jian‐Zhen Zhang. Identification of Rab family genes and functional analyses of LmRab5 and LmRab11A in the development and RNA interference of Locusta migratoria. Insect Science. 2021; ():1.

Chicago/Turabian Style

Mureed Abbas; Yun‐He Fan; Xue‐Kai Shi; Lu Gao; Yan‐Li Wang; Tao Li; Anastasia M.W. Cooper; Kristopher Silver; Kun Yan Zhu; Jian‐Zhen Zhang. 2021. "Identification of Rab family genes and functional analyses of LmRab5 and LmRab11A in the development and RNA interference of Locusta migratoria." Insect Science , no. : 1.

Research article
Published: 19 April 2021 in Archives of Insect Biochemistry and Physiology
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High specificity for silencing target genes and single‐copy target genes that yield clear phenotypes are two important factors for the success of RNA interference (RNAi). The lethal giant larvae (Lgl) gene appears to be an ideal gene for RNAi because RNAi can effectively suppress its expression and results in molting defects and mortality in Tribolium castaneum. To investigate the suitability of this gene for RNAi in other insects, we identified and characterized DvLgl from the western corn rootworm, Diabrotica virgifera virgifera, a species exhibiting high RNAi efficiency. DvLgl was expressed in all developmental stages and tissues investigated. The deduced DvLgl protein showed high amino‐acid sequence identities and similar domain architecture to Lgls from other insect species. Despite many similarities among insect Lgls, RNAi‐mediated suppression of DvLgl failed to produce a phenotype in D. v. virgifera adults. The difference in developing phenotypes could be attributed greatly to the level of gene suppression and the insect developmental stages for RNAi. These results highlight the variability in RNAi response among insects and showcase the importance of screening multiple target genes when conducting RNAi studies. Our findings are expected to help the design of future RNAi studies and future investigations of Lgl in insects.

ACS Style

Anastasia M. W. Cooper; Huifang Song; Xuekai Shi; Zhitao Yu; Young Ho Kim; Kristopher Silver; Jianzhen Zhang; Kun Yan Zhu. Molecular characterization and RNA interference responses of the lethal giant larvae gene in Diabrotica virgifera virgifera adults. Archives of Insect Biochemistry and Physiology 2021, 107, e21787 .

AMA Style

Anastasia M. W. Cooper, Huifang Song, Xuekai Shi, Zhitao Yu, Young Ho Kim, Kristopher Silver, Jianzhen Zhang, Kun Yan Zhu. Molecular characterization and RNA interference responses of the lethal giant larvae gene in Diabrotica virgifera virgifera adults. Archives of Insect Biochemistry and Physiology. 2021; 107 (2):e21787.

Chicago/Turabian Style

Anastasia M. W. Cooper; Huifang Song; Xuekai Shi; Zhitao Yu; Young Ho Kim; Kristopher Silver; Jianzhen Zhang; Kun Yan Zhu. 2021. "Molecular characterization and RNA interference responses of the lethal giant larvae gene in Diabrotica virgifera virgifera adults." Archives of Insect Biochemistry and Physiology 107, no. 2: e21787.

Journal article
Published: 15 April 2021 in Environmental Pollution
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Chronic exposure to pyrethroid insecticides can result in strong selective pressures on non-target species in aquatic systems and drive the evolution of resistance and population-level changes. Characterizing the underlying mechanisms of resistance is essential to better understanding the potential consequences of contaminant-driven microevolution. The current study found that multiple mechanisms enhance the overall tolerance of Hyalella azteca to the pyrethroid permethrin. In H. azteca containing mutations in the voltage-gated sodium channel (VGSC), both adaptation and acclimation played a role in mitigating the adverse effects of pyrethroid exposures. Pyrethroid resistance is primarily attributed to the heritable mutation at a single locus of the VGSC, resulting in reduced target-site sensitivity. However, additional pyrethroid tolerance was conferred through enhanced enzyme-mediated detoxification. Cytochrome P450 monooxygenases (CYP450) and general esterases (GE) significantly contributed to the detoxification of permethrin in H. azteca. Over time, VGSC mutated H. azteca retained most of their pyrethroid resistance, though there was some increased sensitivity from parent to offspring when reared in the absence of pyrethroid exposure. Permethrin median lethal concentrations (LC50s) declined from 1809 ng/L in parent (P0) individuals to 1123 ng/L in the first filial (F1) generation, and this reduction in tolerance was likely related to alterations in acclimation mechanisms, rather than changes to target-site sensitivity. Enzyme bioassays indicated decreased CYP450 and GE activity from P0 to F1, whereas the VGSC mutation was retained. The permethrin LC50s in resistant H. azteca were still two orders-of-magnitude higher than non-resistant populations indicating that the largest proportion of resistance was maintained through the inherited VGSC mutation. Thus, the noted variation in tolerance in H. azteca is likely associated with inducible traits controlling enzyme pathways. A better understanding of the mechanistic and genomic basis of acclimation is necessary to more accurately predict the ecological and evolutionary consequences of contaminant-driven change in H. azteca.

ACS Style

Courtney Y. Fung; Kun Yan Zhu; Kaley Major; Helen C. Poynton; Kara E. Huff Hartz; Gary Wellborn; Michael J. Lydy. The contribution of detoxification pathways to pyrethroid resistance in Hyalella azteca. Environmental Pollution 2021, 284, 117158 .

AMA Style

Courtney Y. Fung, Kun Yan Zhu, Kaley Major, Helen C. Poynton, Kara E. Huff Hartz, Gary Wellborn, Michael J. Lydy. The contribution of detoxification pathways to pyrethroid resistance in Hyalella azteca. Environmental Pollution. 2021; 284 ():117158.

Chicago/Turabian Style

Courtney Y. Fung; Kun Yan Zhu; Kaley Major; Helen C. Poynton; Kara E. Huff Hartz; Gary Wellborn; Michael J. Lydy. 2021. "The contribution of detoxification pathways to pyrethroid resistance in Hyalella azteca." Environmental Pollution 284, no. : 117158.

Journal article
Published: 10 April 2021 in Agronomy
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Dectes texanus larvae girdles the stems of soybean and cultivated sunflowers causing significant yield losses in North America. The soybean Plant Introduction (PI) 165673 exhibits antibiosis resistance to the larval stage. The objectives of this study were: (1) to determine the inheritance of D. texanus resistance in PI165673; (2) evaluate PI165673 antibiosis resistance before 21 d post infestation; (3) evaluate girdling damage in PI16563 at the end of the season. K07-1544/PI165673 F2 and F2:3 populations were tested for resistance to D. texanus in 2011 and 2012, and PI165673 antibiosis resistance and girdling damage were evaluated in 2014. Segregation for resistance to D. texanus and heritability estimates in the F2 and F2:3 populations indicated that resistance was controlled by two genes with dominant and recessive epistasis. Antibiosis evaluations indicated: (1) PI165673 contained lower number of larvae and eggs relative to the number of oviposition punctures at 15 d post infestation; (2) the proportion of first-instar larvae was higher in PI165673 at 15 d post infestation; (3) larvae reach the sixth-instar stage in PI165673. None of the PI165673 plants were girdled at the end of the season. Identification of additional sources of D. texanus resistance is required to impair larval development in the stem.

ACS Style

Lina Aguirre-Rojas; Lawrent Buschman; Brian McCornack; William Schapaugh; Erin Scully; Kun Zhu; Harold Trick; Charles Smith. Inheritance of Antibiosis Resistance to the Dectes Stem Borer, Dectes texanus, in Soybean PI165673. Agronomy 2021, 11, 738 .

AMA Style

Lina Aguirre-Rojas, Lawrent Buschman, Brian McCornack, William Schapaugh, Erin Scully, Kun Zhu, Harold Trick, Charles Smith. Inheritance of Antibiosis Resistance to the Dectes Stem Borer, Dectes texanus, in Soybean PI165673. Agronomy. 2021; 11 (4):738.

Chicago/Turabian Style

Lina Aguirre-Rojas; Lawrent Buschman; Brian McCornack; William Schapaugh; Erin Scully; Kun Zhu; Harold Trick; Charles Smith. 2021. "Inheritance of Antibiosis Resistance to the Dectes Stem Borer, Dectes texanus, in Soybean PI165673." Agronomy 11, no. 4: 738.

Review
Published: 13 January 2021 in Pest Management Science
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Low RNA interference (RNAi) efficiency in many insect pests has significantly prevented its widespread application for insect pest management. This article provides a comprehensive review on recent research in developing various strategies for enhancing RNAi efficiency. Our review focuses on the strategies in target gene selection and double‐stranded RNA (dsRNA) delivery technologies. For target gene selection, genome‐wide or large‐scale screening strategies have been used to identify most susceptible target genes for RNAi. Other strategies include the design of dsRNA constructs and manipulate the structure of dsRNA to maximize the RNA efficiency for a target gene. For dsRNA delivery strategies, much of recent research has focused on the applications of complexed or encapsulated dsRNA using various reagents, polymers, or peptides to enhance dsRNA stability and cellular uptake. Other dsRNA delivery strategies include genetic engineering of microbes (e.g., fungi, bacteria, and viruses) and plants to produce insect‐specific dsRNA. The ingestion of the dsRNA‐producing organisms or tissues will cause lethal or detrimental effects on the target insect pests. This article has also identified obstacles to further developing RNAi for insect pest management and suggests future avenues of research that will maximize the potential for using RNAi for insect pest management.

ACS Style

Kristopher Silver; Anastasia M.W. Cooper; Kun Yan Zhu. Strategies for enhancing the efficiency of RNA interference in insects. Pest Management Science 2021, 77, 2645 -2658.

AMA Style

Kristopher Silver, Anastasia M.W. Cooper, Kun Yan Zhu. Strategies for enhancing the efficiency of RNA interference in insects. Pest Management Science. 2021; 77 (6):2645-2658.

Chicago/Turabian Style

Kristopher Silver; Anastasia M.W. Cooper; Kun Yan Zhu. 2021. "Strategies for enhancing the efficiency of RNA interference in insects." Pest Management Science 77, no. 6: 2645-2658.

Journal article
Published: 25 December 2020 in Journal of Insect Physiology
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RNA interference (RNAi) is commonly used in the laboratory to analyze gene function, and RNAi-based pest management strategies are now being employed. Unfortunately, RNAi is hindered by inefficient and highly-variable results when different insects are targeted, especially lepidopterans, such as the European corn borer (ECB), Ostrinia nubilalis (Lepidoptera: Crambidae). Previous efforts to achieve RNAi-mediated gene suppression in ECB revealed low RNAi efficiency with both double-stranded RNA (dsRNA) injection and ingestion. One mechanism that can affect RNAi efficiency in insects is the expression and function of core RNAi pathway genes, such as those encoding Argonaut 2 (Ago2), Dicer 2 (Dcr2), and a dsRNA binding protein (R2D2). To determine if deficiencies in these core RNAi pathway genes contribute to low RNAi efficiency in ECB, full-length complementary DNAs encoding OnAgo2, OnDcr2, and OnR2D2 were cloned, sequenced, and characterized. A comparison of domain architecture suggested that all three predicted proteins contained the necessary domains to function. However, a comparison of evolutionary distances revealed potentially important variations in the first RNase III domain of OnDcr2, the double-stranded RNA binding domains of OnR2D2, and both the PAZ and PIWI domains of OnAgo2, which may indicate functional differences in enzymatic activity between species. Expression analysis indicated that transcripts for all three genes were expressed in all developmental stages and tissues investigated. Interestingly, the introduction of non-target dsRNA into ECB second-instar larvae via microinjection did not affect OnAgo2, OnDcr2, or OnR2D2 expression. In contrast, ingestion of the same dsRNAs resulted in upregulation of OnDcr2 but downregulation of OnR2D2. The unexpected transcriptional responses of the core machinery and the divergence in amino-acid sequence between specific domains in each core RNAi protein may possibly contribute to low RNAi efficiency in ECB. Understanding the contributions of different RNAi pathway components is critical to adapting this technology for use in controlling lepidopteran pests that exhibit low RNAi efficiency.

ACS Style

Anastasia M.W. Cooper; Huifang Song; Xuekai Shi; Zhitao Yu; Marcé Lorenzen; Kristopher Silver; Jianzhen Zhang; Kun Yan Zhu. Characterization, expression patterns, and transcriptional responses of three core RNA interference pathway genes from Ostrinia nubilalis. Journal of Insect Physiology 2020, 129, 104181 .

AMA Style

Anastasia M.W. Cooper, Huifang Song, Xuekai Shi, Zhitao Yu, Marcé Lorenzen, Kristopher Silver, Jianzhen Zhang, Kun Yan Zhu. Characterization, expression patterns, and transcriptional responses of three core RNA interference pathway genes from Ostrinia nubilalis. Journal of Insect Physiology. 2020; 129 ():104181.

Chicago/Turabian Style

Anastasia M.W. Cooper; Huifang Song; Xuekai Shi; Zhitao Yu; Marcé Lorenzen; Kristopher Silver; Jianzhen Zhang; Kun Yan Zhu. 2020. "Characterization, expression patterns, and transcriptional responses of three core RNA interference pathway genes from Ostrinia nubilalis." Journal of Insect Physiology 129, no. : 104181.

Original article
Published: 03 November 2020 in Insect Science
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The efficiency of RNA interference (RNAi) varies substantially among different insect species. Rapid degradation of double-stranded RNA (dsRNA) by dsRNA-degrading nucleases (dsRNases) has been implicated to cause low RNAi efficiency in several insect species. In this study, we identified four dsRNase genes (OfdsRNase1, OfdsRNase2, OfdsRNase3 and OfdsRNase4) from the Asian corn borer (Ostrinia furnacalis) transcriptome database. Bioinformatic analyses showed that each deduced protein sequence contained endonuclease NS domains and signal peptides. Gene expression analysis revealed that OfdsRNase2 was exclusively expressed in the midgut of larvae. RNAi efficiency was investigated in 2-d-old fifth-instar larvae (high expression of dsRNase2) and 2-d-old pupae (low expression of dsRNase2) by feeding or injecting dsRNA targeting a marker gene that encodes the lethal giant larvae protein (OfLgl). Our results showed that OfLgl only partially silenced the expression of OfLgl in pupae, but not in larvae, suggesting that OfdsRNase2 could contribute to lower RNAi efficiency in larval stages. This hypothesis was supported by our RNAi-of-RNAi experiment using a tissue culture technique where the silencing efficiency against the reporter gene, OfHex1, was significantly improved after knockdown of OfdsRNase2. When double luciferase assays were performed to evaluate the role of the four dsRNases in vitro, only OfdsRNase2 expressed in S2 cells significantly affected RNAi efficiency by degrading dsRNA. Taken together, our results suggested that the degradation of dsRNA by OfdsRNase2 in the midgut contributed to low RNAi efficiency in O. furnacalis larvae.

ACS Style

Yun‐He Fan; Hui‐Fang Song; Mureed Abbas; Yan‐Li Wang; Tao Li; En‐Bo Ma; Anastasia M.W. Cooper; Kristopher Silver; Kun Yan Zhu; Jian‐Zhen Zhang. A dsRNA‐degrading nuclease (dsRNase2) limits RNAi efficiency in the Asian corn borer ( Ostrinia furnacalis ). Insect Science 2020, 1 .

AMA Style

Yun‐He Fan, Hui‐Fang Song, Mureed Abbas, Yan‐Li Wang, Tao Li, En‐Bo Ma, Anastasia M.W. Cooper, Kristopher Silver, Kun Yan Zhu, Jian‐Zhen Zhang. A dsRNA‐degrading nuclease (dsRNase2) limits RNAi efficiency in the Asian corn borer ( Ostrinia furnacalis ). Insect Science. 2020; ():1.

Chicago/Turabian Style

Yun‐He Fan; Hui‐Fang Song; Mureed Abbas; Yan‐Li Wang; Tao Li; En‐Bo Ma; Anastasia M.W. Cooper; Kristopher Silver; Kun Yan Zhu; Jian‐Zhen Zhang. 2020. "A dsRNA‐degrading nuclease (dsRNase2) limits RNAi efficiency in the Asian corn borer ( Ostrinia furnacalis )." Insect Science , no. : 1.

Research article
Published: 01 October 2020 in Pest Management Science
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BACKGROUND Targeting insect‐specific genes through post‐transcriptional gene silencing with RNA interference (RNAi) is a new strategy for insect pest management. However, lepidopterans are recalcitrant to RNAi, which prevents the application of novel RNAi technology to many notorious pests, including Ostrinia nubilalis (ECB). Strategies for enhancing RNAi efficiency, including large doses of double‐stranded RNA (dsRNA), nuclease inhibitors, transfection reagents, and nanoparticles, have proved useful in other insects exhibiting substantial dsRNA degradation, a major mechanism limiting RNAi efficacy. To determine if similar strategies can enhance RNAi efficiency in ECB, various reagents were tested for their ability to enhance dsRNA stability in ECB tissues, then compared for their effectiveness in whole ECB. RESULTS Ex vivo incubation experiments revealed that Metafectene Pro, EDTA, chitosan‐based dsRNA nanoparticles, and Zn2+ enhanced dsRNA stability in ECB hemolymph and gut content extracts, compared to uncoated dsRNA. Despite these positive results, the reagents used in this study were ineffective at enhancing RNAi efficiency in ECB in vivo. To reduce assay time and required dsRNA, midguts were dissected and incubated in tissue culture medium containing dsRNA with and without reagents. These experiments showed that RNAi efficiency varied between target genes, and nuclease inhibitors improved RNAi efficiency for only a portion of the refractory target genes investigated ex vivo. CONCLUSION These results indicate that enhancing dsRNA stability is insufficient to improve RNAi efficiency in ECB and suggests the existence of additional, complex mechanisms contributing to low RNAi efficiency in ECB.

ACS Style

Anastasia M.W. Cooper; Huifang Song; Zhitao Yu; Marie Biondi; Jun Bai; Xuekai Shi; Zhaoyang Ren; Sahani M. Weerasekara; Duy H. Hua; Kristopher Silver; Jianzhen Zhang; Kun Yan Zhu. Comparison of strategies for enhancing RNA interference efficiency in Ostrinia nubilalis. Pest Management Science 2020, 77, 635 -645.

AMA Style

Anastasia M.W. Cooper, Huifang Song, Zhitao Yu, Marie Biondi, Jun Bai, Xuekai Shi, Zhaoyang Ren, Sahani M. Weerasekara, Duy H. Hua, Kristopher Silver, Jianzhen Zhang, Kun Yan Zhu. Comparison of strategies for enhancing RNA interference efficiency in Ostrinia nubilalis. Pest Management Science. 2020; 77 (2):635-645.

Chicago/Turabian Style

Anastasia M.W. Cooper; Huifang Song; Zhitao Yu; Marie Biondi; Jun Bai; Xuekai Shi; Zhaoyang Ren; Sahani M. Weerasekara; Duy H. Hua; Kristopher Silver; Jianzhen Zhang; Kun Yan Zhu. 2020. "Comparison of strategies for enhancing RNA interference efficiency in Ostrinia nubilalis." Pest Management Science 77, no. 2: 635-645.

Journal article
Published: 23 September 2020 in Insects
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Variable RNA interference (RNAi) efficiencies limit RNAi-based pest management strategies for many pests. Previous efforts to understand mechanisms contributing to low RNAi efficiency indicate that double-stranded RNA (dsRNA) is degraded in the European corn borer (ECB), Ostrinia nubilalis, due to nuclease activity. To investigate the contribution of dsRNA-degrading endonucleases (dsRNases) and lepidopteran-specific RNAi efficiency-related nucleases (REases) to dsRNA instability and low RNAi efficiency in ECB, five complementary DNAs putatively encoding four dsRNases (OndsRNase1, 2, 3, and 4) and one REase (OnREase) were sequenced. Characterization of these transcripts revealed that substrate specificity might vary among the four dsRNases due to different amino acid combinations in the substrate-binding sites. Gene expression analysis indicated that OndsRNase2 and OnREase were highly expressed in the larval gut, and OndsRNase1 showed the highest expression in hemolymph, especially in older developmental stages. Transcript level analysis after dsRNA exposure revealed that expression of OnREase rapidly increased upon dsRNA ingestion or injection, whereas OndsRNase4 expression only increased after long-term ingestion of dsRNA. While the biological function of these nucleases remains to be verified, our results suggest that OnREase and OndsRNase2, and OndsRNase1 and OndsRNase4 may be responsible for degradation of dsRNAs in the ECB gut and hemolymph, respectively, thereby contributing to low RNAi efficiency.

ACS Style

Anastasia M. W. Cooper; Huifang Song; Xuekai Shi; Zhitao Yu; Marcé Lorenzen; Kristopher Silver; Jianzhen Zhang; Kun Yan Zhu. Molecular Characterizations of Double-Stranded RNA Degrading Nuclease Genes from Ostrinia nubilalis. Insects 2020, 11, 652 .

AMA Style

Anastasia M. W. Cooper, Huifang Song, Xuekai Shi, Zhitao Yu, Marcé Lorenzen, Kristopher Silver, Jianzhen Zhang, Kun Yan Zhu. Molecular Characterizations of Double-Stranded RNA Degrading Nuclease Genes from Ostrinia nubilalis. Insects. 2020; 11 (10):652.

Chicago/Turabian Style

Anastasia M. W. Cooper; Huifang Song; Xuekai Shi; Zhitao Yu; Marcé Lorenzen; Kristopher Silver; Jianzhen Zhang; Kun Yan Zhu. 2020. "Molecular Characterizations of Double-Stranded RNA Degrading Nuclease Genes from Ostrinia nubilalis." Insects 11, no. 10: 652.

Journal article
Published: 12 September 2020 in Pesticide Biochemistry and Physiology
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Argonautes (Ago) are important core proteins in RNA interference (RNAi) pathways of eukaryotic cells. Generally, it is thought that Ago1, Ago2 and Ago3 are involved in the miRNA (microRNA), siRNA (small interfering RNA) and piRNA (Piwi-interacting RNA)-mediated RNAi pathways, respectively. As a main component of the RNA-induced silencing complex (RISC), Ago2 plays an indispensable role in using siRNA to recognize and cut target messenger RNAs resulting in suppression of transcript levels, but the contributions of Ago1 and Ago3 to the siRNA-mediated RNAi pathway remain to be explored in many insect species. In this study, we investigated the contributions of four Ago genes (named LmAgo1, LmAgo2a and LmAgo2b and LmAgo3) to RNAi efficiency in Locusta migratoria by using both in vivo and in vitro experiments. Our results showed that suppression of each of the Ago genes significantly impaired RNAi efficiency when targeting Lmβ-tubulin transcripts, resulting in recovery of 48, 43.3, 61.4 or 26% of Lmβ-tubulin transcripts following RNAi-mediated suppression of LmAgo1, LmAgo2a, LmAgo2b, and LmAgo3, respectively. Furthermore, overexpression of LmAgo1, LmAgo2a, LmAgo2b, or LmAgo3 in a PAc5.1-V5/HisB vector and co-transfection with psicheck2 fluorescence vector in S2 cells reduced luciferase fluorescence by 38.3, 58.9, 53.3 or 55.6%, respectively. Taken together, our results showed that LmAgo1, LmAgo2a, LmAgo2b, and LmAgo3 each make significant contributions to RNAi efficiency in L. migratoria and suggest that the involvement of all four enzymes could be one of the major factors supporting robust RNAi responses observed in this species.

ACS Style

Lu Gao; Yanli Wang; Yunhe Fan; Mureed Abbas; Enbo Ma; Anastasia M.W. Cooper; Kristopher Silver; Kun Yan Zhu; Jianzhen Zhang. Multiple Argonaute family genes contribute to the siRNA-mediated RNAi pathway in Locusta migratoria. Pesticide Biochemistry and Physiology 2020, 170, 104700 .

AMA Style

Lu Gao, Yanli Wang, Yunhe Fan, Mureed Abbas, Enbo Ma, Anastasia M.W. Cooper, Kristopher Silver, Kun Yan Zhu, Jianzhen Zhang. Multiple Argonaute family genes contribute to the siRNA-mediated RNAi pathway in Locusta migratoria. Pesticide Biochemistry and Physiology. 2020; 170 ():104700.

Chicago/Turabian Style

Lu Gao; Yanli Wang; Yunhe Fan; Mureed Abbas; Enbo Ma; Anastasia M.W. Cooper; Kristopher Silver; Kun Yan Zhu; Jianzhen Zhang. 2020. "Multiple Argonaute family genes contribute to the siRNA-mediated RNAi pathway in Locusta migratoria." Pesticide Biochemistry and Physiology 170, no. : 104700.

Journal article
Published: 01 August 2020 in Pesticide Biochemistry and Physiology
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RNA interference (RNAi) is a revolutionary technique for silencing gene expression, but the success of this technique is dependent upon the stability of double-stranded RNA (dsRNA) molecules. In many insects, especially lepidopteran species, RNAi efficiency is limited by high instability of dsRNA in the gut and/or hemolymph, preventing the development of RNAi-based strategies for many serious pests. Previous attempts to perform RNAi on Ostrinia nubilalis (ECB, Lepidoptera: Crambidae) indicate low RNAi efficiency with both dsRNA injection and feeding. To investigate the contribution of dsRNA instability to low RNAi efficiency in ECB, a serious of ex vivo incubation experiments were performed where dsRNA integrity was assessed following incubation in larval gut continents and hemolymph using gel electrophoresis or RT-qPCR. DsRNA was less stable in the gut contents from ECB than in gut contents from Diabrotica virgifera virgifera, a coleopteran exhibiting high RNAi efficiency. Furthermore, characterization of dsRNA stability in ECB gut contents and hemolymph revealed that dsRNA was rapidly degraded under physiologically relevant conditions as a result of enzymatic activity that was neither size- nor sequence-dependent. These findings suggest that instability of dsRNA in ECB tissues is a contributing factor to the poor efficiency of RNAi in this pest. This work advances our understanding of mechanisms impacting RNAi efficiency in ECB and related lepidopteran insects for which novel pest management strategies are needed, and may facilitate the development of strategies for enhancing dsRNA stability in ECB tissues.

ACS Style

Anastasia M.W. Cooper; Zhitao Yu; Marie Biondi; Huifang Song; Kristopher Silver; Jianzhen Zhang; Kun Yan Zhu. Stability of double-stranded RNA in gut contents and hemolymph of Ostrinia nubilalis larvae. Pesticide Biochemistry and Physiology 2020, 169, 104672 .

AMA Style

Anastasia M.W. Cooper, Zhitao Yu, Marie Biondi, Huifang Song, Kristopher Silver, Jianzhen Zhang, Kun Yan Zhu. Stability of double-stranded RNA in gut contents and hemolymph of Ostrinia nubilalis larvae. Pesticide Biochemistry and Physiology. 2020; 169 ():104672.

Chicago/Turabian Style

Anastasia M.W. Cooper; Zhitao Yu; Marie Biondi; Huifang Song; Kristopher Silver; Jianzhen Zhang; Kun Yan Zhu. 2020. "Stability of double-stranded RNA in gut contents and hemolymph of Ostrinia nubilalis larvae." Pesticide Biochemistry and Physiology 169, no. : 104672.

Journal article
Published: 27 June 2020 in Pesticide Biochemistry and Physiology
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Cytochrome P450 monooxygenases (CYPs) serve many functions in insects, from the regulation of development to xenobiotic detoxification. Several conserved CYPs have been shown to play a role in insect growth and development. CYP303A1 is a highly conserved CYP with a single ortholog in most insects, but its underlying molecular characteristics and specific physiological functions remain poorly understood. In Drosophila melanogaster and Locusta migratoria, CYP303A1 is indispensable for eclosion to adult. Here, we report additional functions of the locust gene LmCYP303A1 in nymphal molts, cuticular lipid deposition and insecticide penetration. RT-qPCR revealed that LmCYP303A1 had a high expression level before ecdysis and was highly expressed in integument, wing pads, foregut and hindgut. Suppression of LmCYP303A1 expression by RNA interference (RNAi) caused a lethal phenotype with molting defect from nymph to nymph. In addition, LmCYP303A1 RNAi resulted in locusts being more susceptible to desiccation and to insecticide toxicity. Furthermore, knockdown of LmCYP303A1 efficiently suppressed the transcript level of key genes (ELO7, FAR15 and CYP4G102) responsible for cuticular hydrocarbon (CHC) synthesis, which led to a decrease in some CHC levels. Taken together, our results suggest that one of the functions of LmCYP303A1 is to regulate the biosynthesis of CHC, which plays critical roles in protecting locusts from water loss and insecticide penetration.

ACS Style

Lixian Wu; Zhitao Yu; Qiangqiang Jia; Xueyao Zhang; Enbo Ma; Sheng Li; Kun Yan Zhu; René Feyereisen; Jianzhen Zhang. Knockdown of LmCYP303A1 alters cuticular hydrocarbon profiles and increases the susceptibility to desiccation and insecticides in Locusta migratoria. Pesticide Biochemistry and Physiology 2020, 168, 104637 .

AMA Style

Lixian Wu, Zhitao Yu, Qiangqiang Jia, Xueyao Zhang, Enbo Ma, Sheng Li, Kun Yan Zhu, René Feyereisen, Jianzhen Zhang. Knockdown of LmCYP303A1 alters cuticular hydrocarbon profiles and increases the susceptibility to desiccation and insecticides in Locusta migratoria. Pesticide Biochemistry and Physiology. 2020; 168 ():104637.

Chicago/Turabian Style

Lixian Wu; Zhitao Yu; Qiangqiang Jia; Xueyao Zhang; Enbo Ma; Sheng Li; Kun Yan Zhu; René Feyereisen; Jianzhen Zhang. 2020. "Knockdown of LmCYP303A1 alters cuticular hydrocarbon profiles and increases the susceptibility to desiccation and insecticides in Locusta migratoria." Pesticide Biochemistry and Physiology 168, no. : 104637.

Journal article
Published: 28 May 2020 in Journal of Economic Entomology
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Aerosol insecticides are one tool that pest management professionals can utilize as a spatial treatment inside food facilities and storage warehouses. Methods of aerosol application can vary significantly and can affect the spatial pattern of efficacy achieved. We investigated how the location from which an aerosol insecticide is applied inside a mill influenced the spatial dispersal of the insecticide. Treatments were performed using two commercial formulations, pyrethrin + pyriproxyfen (insect growth regulator [IGR]) and pyrethrin + methoprene (IGR), applied at one of three static locations or a fourth application comprising of splitting the application among all three locations. Concrete arenas were placed out at different locations within the mill during applications. At 2, 4, and 6 wk post-aerosol application, Tribolium confusum Jacquelin du Val, confused flour beetle, larvae were added to the concrete arenas and monitored for development and efficacy was evaluated based on percent adult emergence and an efficacy index that ranged from 1 (low) to 21 (high). The spatial pattern of aerosol coverage varied between insecticide formulations and the aerosol application location. Areas of the mill near walls, corners, equipment, and farthest away from the application location had larger zones of low efficacy index values among all four application locations. This study illustrated that the aerosol insecticide formulation, application location, and delivery method all significantly influenced residual efficacies of the insecticides. To increase the overall spatial coverage and IGR efficacy, targeting these areas of a mill floor with the aerosol or additional intervention techniques would increase uniform coverages and overall effectiveness.

ACS Style

Deanna S Scheff; James F Campbell; Frank H Arthur; Kun Yan Zhu. Effects of Aerosol Insecticide Application Location on the Patterns of Residual Efficacy Against Tribolium confusum (Coleoptera: Tenebrionidae) Larvae. Journal of Economic Entomology 2020, 113, 2007 -2015.

AMA Style

Deanna S Scheff, James F Campbell, Frank H Arthur, Kun Yan Zhu. Effects of Aerosol Insecticide Application Location on the Patterns of Residual Efficacy Against Tribolium confusum (Coleoptera: Tenebrionidae) Larvae. Journal of Economic Entomology. 2020; 113 (4):2007-2015.

Chicago/Turabian Style

Deanna S Scheff; James F Campbell; Frank H Arthur; Kun Yan Zhu. 2020. "Effects of Aerosol Insecticide Application Location on the Patterns of Residual Efficacy Against Tribolium confusum (Coleoptera: Tenebrionidae) Larvae." Journal of Economic Entomology 113, no. 4: 2007-2015.

Research article
Published: 18 May 2020 in Pest Management Science
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BACKGROUND Cuticular hydrocarbons (CHCs) play a critical role to prevent desiccation and penetration of xenobiotics in insects. Previous studies have shown that cytochrome P450 subfamily 4G (CYP4G) enzymes are oxidative decarbonylases, essential for CHC biosynthesis. However, it is unclear whether there are functional differences between the two CYP4G genes in most insects. In Locusta migratoria, we have identified two CYP4G genes (LmCYP4G62 and LmCYP4G102 ). LmCYP4G102 plays a critical role in the synthesis of cuticular hydrocarbons, but the function of LmCYP4G62 was unknown. RESULTS We identified, characterized and compared two LmCYP4G genes, based on L. migratoria transcriptomic and genomic databases. RT‐qPCR showed that both were highly expressed in tissues to which oenocytes are associated, the integument and fat body. Immunostaining indicated that LmCYP4G62 and LmCYP4G102 were highly abundant in oenocytes in these tissues. However, the two enzymes had a different subcellular distribution, with LmCYP4G62 localized on the plasma membrane and LmCYP4G102 dispersed throughout the oenocyte cytoplasm, presumably on the endoplasmic reticulum. RNAi‐mediated gene silencing against each of the two genes resulted in reduced cuticular hydrocarbon contents, in all classes of CHC for LmCYP4G102 , but mostly shorter chain CHC for LmCYP4G62 . Gene silencing of both genes resulted in increased insecticide penetration through the cuticle, and increased locust susceptibility to desiccation and insecticides. CONCLUSION Our studies suggest that both LmCYP4G62 and LmCYP4G102 contribute to hydrocarbon biosynthesis and play key roles in protecting locusts from water loss and insecticide penetration but they are not fully redundant. Further, the two LmCYP4G genes might be used as new targets for insect pest management. This article is protected by copyright. All rights reserved.

ACS Style

Lixian Wu; Zhan‐Feng Zhang; Zhitao Yu; Rongrong Yu; Enbo Ma; Yong‐Liang Fan; Tong‐Xian Liu; René Feyereisen; Kun Yan Zhu; Jianzhen Zhang. Both LmCYP4G genes function in decreasing cuticular penetration of insecticides in Locusta migratoria. Pest Management Science 2020, 76, 3541 -3550.

AMA Style

Lixian Wu, Zhan‐Feng Zhang, Zhitao Yu, Rongrong Yu, Enbo Ma, Yong‐Liang Fan, Tong‐Xian Liu, René Feyereisen, Kun Yan Zhu, Jianzhen Zhang. Both LmCYP4G genes function in decreasing cuticular penetration of insecticides in Locusta migratoria. Pest Management Science. 2020; 76 (11):3541-3550.

Chicago/Turabian Style

Lixian Wu; Zhan‐Feng Zhang; Zhitao Yu; Rongrong Yu; Enbo Ma; Yong‐Liang Fan; Tong‐Xian Liu; René Feyereisen; Kun Yan Zhu; Jianzhen Zhang. 2020. "Both LmCYP4G genes function in decreasing cuticular penetration of insecticides in Locusta migratoria." Pest Management Science 76, no. 11: 3541-3550.

Journal article
Published: 15 May 2020 in Journal of Economic Entomology
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Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and Trogoderma variabile Ballion (Coleoptera: Dermestidae) are two stored-product insects that cause extensive damage to a variety of postharvest commodities. Long-lasting insecticide-incorporated netting (LLIN), commonly used to control vector-borne diseases in tropical regions, has only been recently studied in an agricultural setting. While prior research showed that LLIN was successful against stored-product beetles, little is known about differential susceptibility among stored-product insect life stages. The aim of this study was to evaluate LLIN efficacy against immature T. castaneum and T. variabile compared with adults. Movement and dispersal ability were evaluated after exposure to LLIN or an untreated, control netting. For the movement assay, video-tracking software recorded the postexposure effects of LLIN on distance traveled and velocity of the insects in 2-h trials. For the dispersal assay, insects were exposed to the netting then released into one end of a PVC pipe and allowed 48 h to disperse to a novel food patch located at the opposite end of the pipe. Our study found that movement and dispersal ability of T. variabile and T. castaneum are significantly reduced, often by multiple-fold, after LLIN exposure, with the larval stage of each species more tolerant to the insecticide netting than adults. These results indicate that LLIN is a promising tool for use in intercepting immigrating insects of different life stages in food facilities to protect stored products.

ACS Style

Rachel V Wilkins; Kun Yan Zhu; James F Campbell; William R Morrison. Mobility and Dispersal of Two Cosmopolitan Stored-Product Insects Are Adversely Affected by Long-Lasting Insecticide Netting in a Life Stage-Dependent Manner. Journal of Economic Entomology 2020, 113, 1768 -1779.

AMA Style

Rachel V Wilkins, Kun Yan Zhu, James F Campbell, William R Morrison. Mobility and Dispersal of Two Cosmopolitan Stored-Product Insects Are Adversely Affected by Long-Lasting Insecticide Netting in a Life Stage-Dependent Manner. Journal of Economic Entomology. 2020; 113 (4):1768-1779.

Chicago/Turabian Style

Rachel V Wilkins; Kun Yan Zhu; James F Campbell; William R Morrison. 2020. "Mobility and Dispersal of Two Cosmopolitan Stored-Product Insects Are Adversely Affected by Long-Lasting Insecticide Netting in a Life Stage-Dependent Manner." Journal of Economic Entomology 113, no. 4: 1768-1779.

Research article
Published: 01 May 2020 in Pest Management Science
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BACKGROUND Knickkopf (Knk) proteins play crucial roles in the formation of insect cuticle. Recent studies in the holometabolous insect red flour beetle (Tribolium castaneum) have shown that three Knk genes encoding TcKnk, TcKnk2 and TcKnk3 play different but essential roles at different developmental stages and in different tissues. However, the functions of Knk genes had not been fully explored in hemimetabolous insects such as the migratory locust Locusta migratoria. RESULTS We identified three transcripts of LmKnk‐like genes LmKnk2 and LmKnk3 with the full‐length cDNA sequences, which were named as LmKnk2, LmKnk3‐FL and LmKnk3‐5'. These three transcripts were highly expressed before molting and mainly expressed in the integument. Among these genes, silencing only LmKnk3‐5' by RNA interference (RNAi) caused molting defects and high mortality of the locusts. Injection of dsLmKnk3‐5' dramatically decreased chitin content, but did not affect cuticle laminar ultra‐structures in the integument. After the knockdown of LmKnk3‐5' transcript, lipid deposition on the cuticle surface was impeded, and locusts exhibited increased susceptibility to each of four insecticides in three different classes. However, no visible phenotypic changes were observed after LmKnk2 or LmKnk3‐FL was silenced by RNAi. CONCLUSION We demonstrate that LmKnk3‐5' is essential for cuticle formation in L. migratoria. This contrasts the findings that the cognate protein in T. castaneum TcKnk3‐5' is dispensable for cuticle formation and survival. Hence, we provide some evidence that the function of Knk‐type proteins may be species‐specific. We therefore think that LmKnk3‐5' may be a good target for the application of RNAi‐based technologies for species‐specific insect pest management. This article is protected by copyright. All rights reserved.

ACS Style

Rui Zhang; XiaoMing Zhao; Xiaojian Liu; Xueyao Zhang; Rongrong Yu; Enbo Ma; Bernard Moussian; Kunyan Zhu; Jianzhen Zhang. Effect of RNAi ‐mediated silencing of two Knickkopf family genes ( LmKnk2 and LmKnk3 ) on cuticle formation and insecticide susceptibility in Locusta migratoria. Pest Management Science 2020, 76, 2907 -2917.

AMA Style

Rui Zhang, XiaoMing Zhao, Xiaojian Liu, Xueyao Zhang, Rongrong Yu, Enbo Ma, Bernard Moussian, Kunyan Zhu, Jianzhen Zhang. Effect of RNAi ‐mediated silencing of two Knickkopf family genes ( LmKnk2 and LmKnk3 ) on cuticle formation and insecticide susceptibility in Locusta migratoria. Pest Management Science. 2020; 76 (9):2907-2917.

Chicago/Turabian Style

Rui Zhang; XiaoMing Zhao; Xiaojian Liu; Xueyao Zhang; Rongrong Yu; Enbo Ma; Bernard Moussian; Kunyan Zhu; Jianzhen Zhang. 2020. "Effect of RNAi ‐mediated silencing of two Knickkopf family genes ( LmKnk2 and LmKnk3 ) on cuticle formation and insecticide susceptibility in Locusta migratoria." Pest Management Science 76, no. 9: 2907-2917.

Journal article
Published: 27 April 2020 in Journal of Stored Products Research
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Plant-based products and common repellents have been suggested as promising alternatives for management of stored product insects. In this study, contact toxicity and repellent activity of the safe natural products carvacrol, citronella oil, geraniol, nootkatone, ocimene and R-(+)-pulegone, and the synthetic commercial repellents, N,N-Diethyl-3-methylbenzamide (DEET), and the fatty acid mixture of octanoic, nonanoic, and decanoic acids (C8910) were evaluated against the lesser grain borer, Rhyzopertha dominica and the cigarette beetle, Lasioderma serricorne under laboratory conditions. In contact toxicity assays the compounds were tested at concentrations ranging between 0.008 and 0.4 mg/cm2. Carvacrol and R-(+)-pulegone exhibited the highest contact toxicity with LC50 values of 0.019 and 0.023 mg/cm2 against L. serricorne and LC50 values of 0.012 and 0.019 mg/cm2 against R. dominica, respectively. Similarly, C8910, geraniol and citronella oil showed toxic effect against both insects. The repellent activity of compounds was tested using the preference method assay at concentrations ranging between 3.125 and 50.0 μg/cm2. The highest repellency percentage (RP) was achieved by C8910 against L. serricorne with a RP value of 76.0% at the lowest concentration (6.25 μg/cm2), while carvacrol showed the highest repellent activity against R. dominica with RP value of 88.0% at 3.125 μg/cm2 within 3 h of insect exposure. The tested compounds caused higher repellent activity to R. dominica than L. serricorne. In vitro inhibition studies of acetylcholinesterase (AChE) in adults of both species showed that R-(+) pulegone strongly inhibited AChE activity of R. dominica and L. serricorne with 69.0% and 88.0% inhibition at 40 mM, respectively. Carvacrol caused 41.8% inhibition in AChE activity of R. dominica compared to 66.7% of L. serricorne at 40 mM. The results indicated that the tested natural compounds may be useful alternatives for controlling R. dominica and L. serricorne.

ACS Style

Gomaa R.M. Ramadan; Samir A.M. Abdelgaleil; Mohamed S. Shawir; Ahmed S. El-Bakary; Kun Yan Zhu; Thomas W. Phillips. Terpenoids, DEET and short chain fatty acids as toxicants and repellents for Rhyzopertha dominica (coleoptera: Bostrichidae) and Lasioderma serricorne (Coleoptera: Ptinidae). Journal of Stored Products Research 2020, 87, 101610 .

AMA Style

Gomaa R.M. Ramadan, Samir A.M. Abdelgaleil, Mohamed S. Shawir, Ahmed S. El-Bakary, Kun Yan Zhu, Thomas W. Phillips. Terpenoids, DEET and short chain fatty acids as toxicants and repellents for Rhyzopertha dominica (coleoptera: Bostrichidae) and Lasioderma serricorne (Coleoptera: Ptinidae). Journal of Stored Products Research. 2020; 87 ():101610.

Chicago/Turabian Style

Gomaa R.M. Ramadan; Samir A.M. Abdelgaleil; Mohamed S. Shawir; Ahmed S. El-Bakary; Kun Yan Zhu; Thomas W. Phillips. 2020. "Terpenoids, DEET and short chain fatty acids as toxicants and repellents for Rhyzopertha dominica (coleoptera: Bostrichidae) and Lasioderma serricorne (Coleoptera: Ptinidae)." Journal of Stored Products Research 87, no. : 101610.

Journal article
Published: 01 February 2020 in International Journal of Biological Macromolecules
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Cytochrome P450 monooxygenases (P450s) constitute a large superfamily of heme-thiolate proteins that are involved in the biosynthesis or degradation of endogenous compounds and detoxification of exogenous chemicals. It has been reported that P450s could serve as odorant-degrading enzymes (ODEs) to inactivate odorants to avoid saturating the antennae. However, there is little information about P450s in the antennae of Locusta migratoria. In the current work, we conducted an antenna transcriptome analysis and identified 92 P450s, including 68 full-length and 24 partial sequences. Phylogenetic analysis showed that 68 full-length P450s were grouped into four clans: CYP2, CYP3, CYP4, and mitochondria clans. Tissue, stage, and sex-dependent expressions of these 68 P450s were investigated. The results showed that 4 P450s were antenna-specific, whereas others were antenna-rich but also expressed in other tissues, implying their various potential roles in the antennae. In addition, the responses of seven selected P450s to five gramineous plant volatiles and four locust volatiles were determined. CYP6MU1 could be induced by almost all compounds tested, suggesting its important roles in odorant processing. Different P450s exhibited diverse responses to odorants, indicating that specific regulation of P450 expression by odorants might modulate the sensitivity of the olfactory responses to various chemicals.

ACS Style

Haihua Wu; YongMei Liu; Xuekai Shi; Xueyao Zhang; Changlü Ye; Kun Yan Zhu; Fang Zhu; Jianzhen Zhang; Enbo Ma. Transcriptome analysis of antennal cytochrome P450s and their transcriptional responses to plant and locust volatiles in Locusta migratoria. International Journal of Biological Macromolecules 2020, 149, 741 -753.

AMA Style

Haihua Wu, YongMei Liu, Xuekai Shi, Xueyao Zhang, Changlü Ye, Kun Yan Zhu, Fang Zhu, Jianzhen Zhang, Enbo Ma. Transcriptome analysis of antennal cytochrome P450s and their transcriptional responses to plant and locust volatiles in Locusta migratoria. International Journal of Biological Macromolecules. 2020; 149 ():741-753.

Chicago/Turabian Style

Haihua Wu; YongMei Liu; Xuekai Shi; Xueyao Zhang; Changlü Ye; Kun Yan Zhu; Fang Zhu; Jianzhen Zhang; Enbo Ma. 2020. "Transcriptome analysis of antennal cytochrome P450s and their transcriptional responses to plant and locust volatiles in Locusta migratoria." International Journal of Biological Macromolecules 149, no. : 741-753.

Review
Published: 07 January 2020 in Annual Review of Entomology
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The RNA interference (RNAi) triggered by short/small interfering RNA (siRNA) was discovered in nematodes and found to function in most living organisms. RNAi has been widely used as a research tool to study gene functions and has shown great potential for the development of novel pest management strategies. RNAi is highly efficient and systemic in coleopterans but highly variable or inefficient in many other insects. Differences in double-stranded RNA (dsRNA) degradation, cellular uptake, inter- and intracellular transports, processing of dsRNA to siRNA, and RNA-induced silencing complex formation influence RNAi efficiency. The basic dsRNA delivery methods include microinjection, feeding, and soaking. To improve dsRNA delivery, various new technologies, including cationic liposome–assisted, nanoparticle-enabled, symbiont-mediated, and plant-mediated deliveries, have been developed. Major challenges to widespread use of RNAi in insect pest management include variable RNAi efficiency among insects, lack of reliable dsRNA delivery methods, off-target and nontarget effects, and potential development of resistance in insect populations.

ACS Style

Kun Yan Zhu; Subba Reddy Palli. Mechanisms, Applications, and Challenges of Insect RNA Interference. Annual Review of Entomology 2020, 65, 293 -311.

AMA Style

Kun Yan Zhu, Subba Reddy Palli. Mechanisms, Applications, and Challenges of Insect RNA Interference. Annual Review of Entomology. 2020; 65 (1):293-311.

Chicago/Turabian Style

Kun Yan Zhu; Subba Reddy Palli. 2020. "Mechanisms, Applications, and Challenges of Insect RNA Interference." Annual Review of Entomology 65, no. 1: 293-311.

Journal article
Published: 04 January 2020 in Journal of Economic Entomology
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This study evaluated the fumigant ethanedinitrile (EDN) against the cigarette beetle, Lasioderma serricorne, and phosphine-resistant and susceptible lesser grain borer, Rhyzopertha dominica, life stages under laboratory conditions. Eggs of both species were the most susceptible stage to EDN. EDN is, therefore, a promising alternative because eggs are generally tolerant to most common fumigants. Lasioderma serricorne eggs were the most susceptible with an LC50 estimated of 50.4 ppm, followed by adults, pupae and larvae with LC50 values of 160.2, 192.5, and 446.6 ppm, respectively, after 24-h exposure at 25°C. Eggs of phosphine-susceptible (LC50 = 11.2 ppm) and resistant (LC50 = 12.0 ppm) R. dominica strains were more susceptible to EDN than were adults of both strains, with LC50 values of 27.7 and 36.0 ppm, respectively. Lasioderma serricorne mixed life stage cultures were completely controlled at concentrations ≥2,000 ppm at 24 h. Fumigation with 600 ppm was enough to suppress adult emergence in the case of the phosphine-susceptible R. dominica strain (USDA), while an average of only 4.0 adults emerged from the phosphine-resistant R. dominica strain (Belle Glade) compared with 514.3 adults in the control. Lasioderma serricorne was more tolerant to EDN than both R. dominica strains. EDN caused 61.8 and 68.2 % inhibition of R. dominica (USDA) cytochrome c oxidase activity at concentrations of 0.0038 and 0.0076 mM in vitro, respectively, and it did not inhibit its activity in the case of an in vivo assay. These results suggest that cytochrome c oxidase may not be the main target for EDN toxicity.

ACS Style

Gomaa R M Ramadan; Kun Yan Zhu; Samir A M Abdelgaleil; Mohamed S Shawir; Ahmed S El-Bakary; Peter Edde; Thomas W Phillips. Ethanedinitrile as a Fumigant for Lasioderma serricorne (Coleoptera: Anobiidae), and Rhyzopertha dominica (Coleoptera: Bostrichidae): Toxicity and Mode of Action. Journal of Economic Entomology 2020, 113, 1519 -1527.

AMA Style

Gomaa R M Ramadan, Kun Yan Zhu, Samir A M Abdelgaleil, Mohamed S Shawir, Ahmed S El-Bakary, Peter Edde, Thomas W Phillips. Ethanedinitrile as a Fumigant for Lasioderma serricorne (Coleoptera: Anobiidae), and Rhyzopertha dominica (Coleoptera: Bostrichidae): Toxicity and Mode of Action. Journal of Economic Entomology. 2020; 113 (3):1519-1527.

Chicago/Turabian Style

Gomaa R M Ramadan; Kun Yan Zhu; Samir A M Abdelgaleil; Mohamed S Shawir; Ahmed S El-Bakary; Peter Edde; Thomas W Phillips. 2020. "Ethanedinitrile as a Fumigant for Lasioderma serricorne (Coleoptera: Anobiidae), and Rhyzopertha dominica (Coleoptera: Bostrichidae): Toxicity and Mode of Action." Journal of Economic Entomology 113, no. 3: 1519-1527.