Deletion mutant of PGE2 receptor using CRISPR-Cas9 exhibits larval immunosuppression and adult infertility in a lepidopteran insect, Spodoptera exigua

2020 ◽  
Vol 111 ◽  
pp. 103743 ◽  
Author(s):  
Yonggyun Kim ◽  
Shabbir Ahmed ◽  
Md Abdullah Al Baki ◽  
Sunil Kumar ◽  
Kunwoo Kim ◽  
...  
Keyword(s):  
Deletion Mutant ◽  
Spodoptera Exigua ◽  
Lepidopteran Insect ◽  
Pge2 Receptor

scholarly journals EpOMEs act as immune suppressors in a lepidopteran insect, Spodoptera exigua

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mohammad Vatanparast ◽  
Shabbir Ahmed ◽  
Dong-Hee Lee ◽  
Sung Hee Hwang ◽  
Bruce Hammock ◽  
...  
Keyword(s):  
Immune Responses ◽  
Epoxide Hydrolase ◽  
Spodoptera Exigua ◽  
Inflammatory Responses ◽  
Soluble Epoxide Hydrolase ◽  
Immune Defense ◽  
Nodule Formation ◽  
Dodecanoic Acid ◽  
Bacterial Challenge ◽  
Lepidopteran Insect

AbstractEpoxyoctadecamonoenoic acids (EpOMEs) are epoxide derivatives of linoleic acid (9,12-octadecadienoic acid) and include 9,10-EpOME and 12,13-EpOME. They are synthesized by cytochrome P450 monooxygenases (CYPs) and degraded by soluble epoxide hydrolase (sEH). Although EpOMEs are well known to play crucial roles in mediating various physiological processes in mammals, their role is not well understood in insects. This study chemically identified their presence in insect tissues: 941.8 pg/g of 9,10-EpOME and 2,198.3 pg/g of 12,13-EpOME in fat body of a lepidopteran insect, Spodoptera exigua. Injection of 9,10-EpOME or 12,13-EpOME into larvae suppressed the cellular immune responses induced by bacterial challenge. EpOME treatment also suppressed the expression of antimicrobial peptide (AMP) genes. Among 139 S. exigua CYPs, an ortholog (SE51385) to human EpOME synthase was predicted and its expression was highly inducible upon bacterial challenge. RNA interference (RNAi) of SE51385 prevented down-regulation of immune responses at a late stage (> 24 h) following bacterial challenge. A soluble epoxide hydrolase (Se-sEH) of S. exigua was predicted and showed specific expression in all development stages and in different larval tissues. Furthermore, its expression levels were highly enhanced by bacterial challenge in different tissues. RNAi reduction of Se-sEH interfered with hemocyte-spreading behavior, nodule formation, and AMP expression. To support the immune association of EpOMEs, urea-based sEH inhibitors were screened to assess their inhibitory activities against cellular and humoral immune responses of S. exigua. 12-(3-adamantan-1-yl-ureido) dodecanoic acid (AUDA) was highly potent in suppressing the immune responses. The addition of AUDA to a pathogenic bacterium significantly increased bacterial pathogenicity by suppressing host immune defense. In sum, this study demonstrated that EpOMEs play a crucial role in facilitating anti-inflammatory responses in S. exigua.

scholarly journals Prostaglandin catabolism in Spodoptera exigua, a lepidopteran insect

2020 ◽  
Author(s):  
Shabbir Ahmed ◽  
Yonggyun Kim
Keyword(s):  
Immune Responses ◽  
Spodoptera Exigua ◽  
Inflammatory Mediator ◽  
Late Phase ◽  
Bacterial Challenge ◽  
Expression Levels ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Lepidopteran Insect ◽  
Rnai Treatment

ABSTRACTSeveral prostaglandins (PGs) and PG-synthesizing enzymes have been identified from insects. PGs can mediate cellular and humoral immune responses. However, uncontrolled and prolonged immune responses might have adverse effects on survival. PG catabolism in insects has not been reported. Here, using a transcriptomic analysis, we predicted two PG-degrading enzymes, PG dehydrogenase (SePGDH) and PG reductase (SePGR), in Spodoptera exigua, a lepidopteran insect. SePGDH and SePGR expression levels were upregulated after immune challenge. However, their expression peaks occurred after those of PG biosynthesis genes such as PGE2 synthase or PGD2 synthase. Indeed, SePGDH and SePGR expression levels were upregulated after injection with PGE2 or PGD2. In contrast, such upregulated expression was not detected after injection with leukotriene B4, an eicosanoid inflammatory mediator. RNA interference (RNAi) using double-stranded RNAs specific to SePGDH or SePGR suppressed their expression levels. The RNAi treatment resulted in an excessive and fatal melanization of larvae even after a non-pathogenic bacterial infection. Phenoloxidase (PO) activity mediating the melanization in larval plasma was induced by bacterial challenge or PGE2 injection. Although the induced PO activity decreased after 8 h in control, larvae treated with dsRNAs specific to PG-degrading enzyme genes kept the high PO activities for a longer period compared to control larvae. These results suggest that SePGDH and SePGR are responsible for PG degradation at a late phase of immune responses.

scholarly journals Evaluation of the sublethal effect of tetrachlorantraniliprole on Spodoptera exigua and its potential toxicity to two non-target organisms

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242052
Author(s):  
Haiyuan Teng ◽  
Yongda Yuan ◽  
Tianshu Zhang ◽  
Xiaoli Chang ◽  
Dongsheng Wang
Keyword(s):  
Spodoptera Exigua ◽  
Harmonia Axyridis ◽  
Sublethal Effects ◽  
Ryanodine Receptors ◽  
Sublethal Effect ◽  
Lepidopteran Insect ◽  
Anthranilic Diamide ◽  
The Mean ◽  
Sublethal Concentrations ◽  
Target Effects

Tetrachlorantraniliprole (TCAP) is a novel anthranilic diamide insecticide that specifically targets the ryanodine receptors of lepidopteran insect species with excellent insecticidal activity. Previous studies have reported the sublethal effects of multiple diamides on several lepidopteran species, whereas the sublethal and non-target effects of TCAP remain largely unknown. We assessed the sublethal effects of TCAP on Spodoptera exigua. We also investigated the effects of TCAP on non-target Harmonia axyridis and Eisenia fetida, S. exigua was more sensitive to TCAP than to chlorantraniliprole, as the LC50 (10.371 μg L-1 at 72 h) of TCAP was relatively lower. Compared with those of the control, sublethal concentrations of TCAP (LC10 and LC30) not only prolonged the duration of the larval and pupal stages as well as the mean generation time but also reduced certain population parameters. On the other hand, TCAP exposure, even at the highest concentration, did not induce toxic effects in H. axyridis ladybugs (1st instar larvae and adults) or E. fetida earthworms. Taken together, our results suggest that TCAP can be used as a novel and promising component of the integrated pest management (IPM) program against S. exigua due to its robust target effects and negligible non-target risks.

scholarly journals CRISPR/Cas9 mutagenesis against sex pheromone biosynthesis leads to loss of female attractiveness in Spodoptera exigua, an insect pestt

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259322
Author(s):  
Shabbir Ahmed ◽  
Miltan Chandra Roy ◽  
Md. Abdullah Al Baki ◽  
Jin Kyo Jung ◽  
Daeweon Lee ◽  
...  
Keyword(s):  
Sex Pheromone ◽  
Sex Pheromones ◽  
Spodoptera Exigua ◽  
Insect Pest ◽  
Virgin Female ◽  
Pheromone Biosynthesis ◽  
Male Mating ◽  
Lepidopteran Insect ◽  
Male Mating Behavior ◽  
Attractive Female

Virgin female moths are known to release sex pheromones to attract conspecific males. Accurate sex pheromones are required for their chemical communication. Sex pheromones of Spodoptera exigua, a lepidopteran insect, contain unsaturated fatty acid derivatives having a double bond at the 12th carbon position. A desaturase of S. exigua (SexiDES5) was proposed to have dual functions by forming double bonds at the 11th and 12th carbons to synthesize Z9,E12-tetradecedienoic acid, which could be acetylated to be a main sex pheromone component Z9,E12-tetradecenoic acetate (Z9E12-14:Ac). A deletion of SexiDES5 using CRISPR/Cas9 was generated and inbred to obtain homozygotes. Mutant females could not produce Z9E12-14:Ac along with Z9-14:Ac and Z11-14:Ac. Subsequently, pheromone extract of mutant females did not induce a sensory signal in male antennae. They failed to induce male mating behavior including hair pencil erection and orientation. In the field, these mutant females did not attract any males while control females attracted males. These results indicate that SexiDES5 can catalyze the desaturation at the 11th and 12th positions to produce sex pheromone components in S. exigua. This study also suggests an application of the genome editing technology to insect pest control by generating non-attractive female moths.

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