Laccase-Based Self-Amplifying Catalytic System Enables Efficient Antibiotic Degradation for Sustainable Environmental Remediation.

Antibiotic contamination poses potential risks to ecosystems and human health. Laccase (LAC) has emerged as a promising biocatalyst for the oxidation of environmentally toxic contaminants with high catalytic efficiency; however, its large-scale application is hindered by enzyme costs and dependency on redox mediators. Herein, a novel self-amplifying catalytic system (SACS) for antibiotic remediation that does not require external mediators is developed. In SACS, a natural mediator-regenerating koji with high-activity LAC, derived from lignocellulosic waste, initiates the chlortetracycline (CTC) degradation. Subsequently, an intermediate product, CTC327, identified as an active mediator for LAC via molecular docking, is formed and then starts a renewable reaction cycle, including CTC327-LAC interaction, stimulated CTC bioconversion, and self-amplifying CTC327 release, thus enabling highly efficient antibiotic bioremediation. In addition, SACS exhibits excellent performance in producing lignocellulose-degrading enzymes, highlighting its potential for lignocellulosic biomass deconstruction. To demonstrate its effectiveness and accessibility in the natural environment, SACS is used to catalyze in situ soil bioremediation and straw degradation. The resulting CTC degradation rate is 93.43%, with a straw mass loss of up to 58.35% in a coupled process. This mediator regeneration and waste-to-resource conversion in SACS provides a promising route for environmental remediation and sustainable agricultural practices.

Nilaparvata lugens ERR2 regulates moulting and ovary development is related to hormone signalling.

The nuclear receptor (NR) superfamily is one of the largest groups of transcription factors in living organisms. Oestrogen related receptor (ERR) is a class of nuclear receptors closely related to oestrogen receptors (ERs). In this study, the Nilaparvata lugens (N. lugens) ERR2 (NlERR2) was cloned, and the expression of NlERR2 was detected by qRT-PCR to explore the distribution of NlERR2 during development and in different tissues. Using RNAi and qRT-PCR, the interaction between NlERR2 and related genes of the 20-hydroxyecdysone (20E) and juvenile hormone (JH) signalling pathways was studied. The results showed that topical application of 20E and juvenile hormone III (JHIII) affected the expression of NlERR2, and NlERR2 could affect the expression of genes related to 20E and JH signalling pathways. Furthermore, NlERR2 and JH/20E hormone signalling-related genes affect moulting and ovarian development. NlERR2 and NlE93/NlKr-h1 affect the transcriptional expression of Vg-related genes. In summary, NlERR2 is related to hormone signalling pathways, which is also related to the expression of Vg and Vg related genes. Brown planthopper is one of the most important rice pests. This study provides an important basis for mining new targets for pest control.

The Function of Nilaparvata lugens (Hemiptera: Delphacidae) E74 and Its Interaction With ßFtz-F1.

Drosophila E74 is an early gene located in the polytene chromosome 74EF puff position. E74 controls the production of late genes, indicating that it plays a crucial role in this cascade model. Nilaparvata lugens E74 is closely related to Diaphorina citri, Bemisia tabaci, and Laodelphax striatellus. After downregulating E74, molting, and nymphal mortality were increased, and ovarian development was delayed. Moreover, the expression of Vg was reduced at the transcriptional level, as measured by qRT-PCR, and the content of Vg protein was reduced, as detected by Western blotting. After downregulating E74, the expression of hormone-related genes, including Tai, ßFtz-F1, Met, Kr-h1, UspA, UspB, E93, and Br, was changed. The expression of E74 was significantly decreased after downregulating hormone-related genes. When the expression of E74 and ßFtz-F1 was downregulated together, nymph mortality and molting mortality were higher than those when E74 or ßFtz-F1 was downregulated alone. Thus, E74 probably interacts with ßFtz-F1 at the genetic level. In summary, this study showed that E74 plays a crucial role in the development, metamorphosis and reproduction of N. lugens, possibly via the interaction with ßFtz-F1 at the genetic level. This study provides a basis for the development of new target-based pesticides and new methods for the effective control of N. lugens.

Role of Groucho and Groucho1-like in Regulating Metamorphosis and Ovary Development in Nilaparvata lugens (Stål).

Juvenile hormone and ecdysone are key regulators in the metamorphosis and development. Grocho (Gro) is a highly conserved protein required for metamorphosis and development. Brown planthopper (Nilaparvata lugens) is a major pest affecting rice production in China and many Asian countries. Although the molecular function of Gro has been investigated in holometabolous insects such as Aedes aegypti and Drosophila melanogaster, their role in the hemimetabolous insect, brown planthopper, and the relationship between NlGro/NlGro1-L and JH/ecdysone signaling pathway, remained unknown. In this study, NlGroucho (NlGro) and NlGroucho1-like (NlGro1-L) were cloned. An analysis of the predicted protein sequence showed that NlGro has highly conserved Q domain and WD40 domain, and NlGro1-L has a highly conserved WD40 domain. The expression profiles of both genes were studied by quantitative real-time PCR (qRT-PCR). Their relative expressions were high in egg, head, wing, ovary, and testis. NlGro and NlGro1-L were found to interact genetically with juvenile hormone and ecdysone signaling by hormone treatment and RNAi of JH/ecdysone signaling-related genes. Moreover, when NlGro or NlGro1-L was down-regulated alone, the survival rate was decreased, the ovarian development was delayed, and the oviposition was also affected. All defects were aggravated when NlGro and NlGro1-L were down-regulated together. This study will help to develop new pesticides on the basis of the function of NlGro and NlGro1-L, and provide new possibilities for the control of Nilaparvata lugens.

Efficient biodegradation of straw and persistent organic pollutants by a novel strategy using recombinant Trichoderma reesei.

Efficient biodegradation of lignocellulosic biomass needs a battery of enzymes targeting cellulose, hemicellulose, and lignin. In this study, recombinant Trichoderma reesei ZJ-09 with Pycnoporus sanguineus laccase gene was used to degrade rice straw by in situ production of laccase, xylanase, and cellulases under solid-state fermentation (SSF). Effects of parameters on key enzymes (cellulase, xylanase, and laccase) in biodegradation during SSF were investigated. Under the optimized SSF conditions, the FPA, xylanase activity, and laccase activity reached 110.47 FPU/g, 5787.59 IU/g, and 24.45 IU/g, respectively, on day 12. The obtained recombinant T. reesei SSF system achieved efficient degradation of rice straw with the final mass loss up to 51.16% which was 1.4-fold higher than the host strain. Further, bioconversion of rice straw into a novel laccase-enriched koji for persistent organic pollutants bioremediation (LKPB) was conducted by the optimized SSF system. LKPB was found to degrade persistent organic pollutants (POPs) effectively without the addition of mediators. 4-h removal rates of three POPs mediated by LKPB (87.21% for 2,4,5-trichlorophenol, 92.45% for nonylphenol, and 90.73% for oxytetracycline) were comparable to those achieved by laccase-co-mediator system. The newly established recombinant T. reesei SSF system could be potential to effectively degrade lignocellulosic wastes as well as organic pollutants.

Protocol for Analyzing Cell Cycle Phases of Polyphenic Wings Using Flow Cytometry.

Deciphering cell cycle phases of polyphenic tissues is an important challenge in understanding the cellular mechanism of polymorphism. We use flow cytometry to analyze cell cycle phases of short wings and long wings of the brown planthopper. This provides information on the arresting cell cycle phases in different wing forms. The protocol could be applied to analysis of the cell cycle phases of other polyphenic insects and in different polyphenic tissues after modification. For complete details on the use and execution of this protocol, please refer to Lin et al. (2020).

Cell Cycle Progression Determines Wing Morph in the Polyphenic Insect Nilaparvata lugens.

Wing polyphenism is a phenomenon in which one genotype can produce two or more distinct wing phenotypes adapted to the particular environment. What remains unknown is how wing pad development is controlled downstream of endocrine signals such as insulin and JNK pathways. We show that genes important in cellular proliferation, cytokinesis, and cell cycle progression are necessary for growth and development of long wings. Wing pad cellular development of the long-winged morph was characterized by a highly structured epithelial layer with microvilli-like structures. Cells of adult short wing pads are largely in the G2/M phase of the cell cycle, whereas those of long wings are largely in G1. Our study is the first to report the comparative developmental and cellular morphology and structure of the wing morphs and to undertake a comprehensive evaluation of the cell cycle genes necessary for wing development of this unique, adaptive life history strategy.

[Effects of silver nanoparticles on pupation, eclosion, life span, apoptosis and protein expression in Drosophila melanogaster]. / 纳米银对果蝇化蛹、羽化、寿命及细胞凋亡和蛋白表达的影响.

Silver nanoparticle is widely used in the field of medicine because of its strong and effective antibacterial action. However, it has potential biological toxicity. In this study, the classical model organism, Drosophila melanogaster, was used to explore underlying mechanism for the toxic effects of silver nanoparticle. The pupation rate, eclosion time, eclosion rate and lifespan of Oregon R, w1118, and MTF mutants under different concentrations of silver nanoparticle were measured. The lacZ activity of rpr-lacZ strain was used to determine apoptosis of imaginal disc after treated with different concentrations of silver nanoparticle. The difference of intestinal protein expression in MTF mutants treated with different concentrations of silver nanoparticle was studied by SDS-PAGE. The amino acid sequence of differential proteins was further analyzed by mass spectrometry. The results showed that pupation rate and eclosion rate of MTF mutants significantly decreased when the concentration of silver nanoparticle increased to 200 µg·mL-1 and above. When the concentration of silver nanoparticle increased to 800 µg·mL-1, the rate of pupation and eclosion was significantly reduced, with the time of pupation and eclosion being not correlated to the concentration of silver nanoparticle. The concentrations of silver nanoparticle had no effect on the lifespan of Oregon R and w1118, while 200 µg·mL-1 silver nanoparticle significantly reduced the average lifespan of MTF mutant. Apoptosis increased with increasing concentration of silver nanoparticle. Results from SDS-PAGE and mass spectrometry analysis showed that the expression levels of proteins such as ATP kinase, heat shock protein and glucose metabolism related enzymes increased with increasing concentration of silver nanoparticle. Our results showed that high concentration of silver nanoparticle would reduce the survival rate of Drosophila, promote apoptosis and the expression of some proteins, which provided a theoretical basis for further understanding of the toxic mechanism of silver nanoparticle.

The Direct Interaction between E93 and Kr-h1 Mediated Their Antagonistic Effect on Ovary Development of the Brown Planthopper.

The juvenile hormone (JH) signalling and ecdysone signalling pathways are crucial endocrine signalling pathways that orchestrate the metamorphosis of insects. The metamorphic process, the morphological change from the immature to adult forms, is orchestrated by the dramatic reduction of JH and downstream transcription factors. The Krüppel-homologue 1 (Kr-h1), a downstream transcription factor of the JH signalling pathway, represses E93 expression with an anti-metamorphic effect. However, the biochemical interaction between Kr-h1 and E93 and how the interaction regulates ovary development, a sensitive readout for endocrine regulation, remain unknown. In brown planthopper, Nilaparvata lugens, we found that the downregulation of Kr-h1 partially recovered the deteriorating effect of E93 knock-down on metamorphosis. Dual knock down of E93 and Kr-h1 increased ovary development and the number of eggs laid when compared to the effects of the knock down of E93 alone, indicating that the knock down of Kr-h1 partially recovered the deteriorating effect of the E93 knock-down on ovary development. In summary, our results indicated that E93 and Kr-h1 have antagonistic effects on regulating metamorphosis and ovary development. We tested the biochemical interaction between these two proteins and found that these molecules interact directly. Kr-h1 V and E93 II undergo strong and specific interactions, indicating that the potential interacting domain may be located in these two regions. We inferred that the nuclear receptor interaction motif (NR-box) and helix-turn-helix DNA binding motifs of the pipsqueak family (RHF1) are candidate domains responsible for the protein-protein interaction between E93 and Kr-h1. Moreover, the HA-tagged E93 and FLAG-tagged Kr-h1 were co-localized in the nucleus, and the expression of E93 was increased when Kr-h1 was downregulated, supporting that these two proteins may interact antagonistically. JH and ecdysone signalling are critical for the control of ovary development and pest populations. Our result is important for understanding the interactions between E93 and related proteins, which makes it possible to identify potential targets and develop new pesticides for pest management.

Complete mitochondrial genome and phylogenetic analysis of a Chorthippus fallax (Zuboxsky) isolated in rangeland of northwest region of China.

In this study, we assembled a complete 16,143 bp mitochondrial genome for Chorthippus fallax (Zuboxsky), which encodes 13 protein-coding genes, 22 tRNAs, 12S and 16S rRNAs and a 722 bp D-loop in the characteristic arrangement of superfamily Acrididae. The most common start codon for 13 PCGs is ATG and the most common termination codon is TAA. The overall A + T content was 75.13%. Phylogenetic analysis based on the entire mitochondrial genome indicated C. fallax (Zuboxsky) had more close relationship with Euchorthippus fusigeniculatus and Chorthippus chinensis in family Arcypteridae, and implied non-monophyly for the family. The data will be important for better understanding of the phylogenetic relationship of members in Acrididae superfamily.

2-(2-Benzofuranyl)-2-imidazoline treatment within 5 hours after cerebral ischemia/reperfusion protects the brain.

We previously demonstrated that administering 2-(2-benzofuranyl)-2-imidazolin (2-BFI), an imidazoline I2 receptor agonist, immediately after ischemia onset can protect the brain from ischemic insult. However, immediate administration after stroke is difficult to realize in the clinic. Thus, the therapeutic time window of 2-BFI should be determined. Sprague-Dawley rats provided by Wenzhou Medical University in China received right middle cerebral artery occlusion for 120 minutes, and were treated with 2-BFI (3 mg/kg) through the caudal vein at 0, 1, 3, 5, 7, and 9 hours after reperfusion. Neurological function was assessed using the Longa's method. Infarct volume was measured by 2,3,5-triphenyltetrazolium chloride assay. Morphological changes in the cortical penumbra were observed by hematoxylin-eosin staining under transmission electron microscopy . The apoptosis levels in the ipsilateral cortex were examined with terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay. The protein expression of Bcl-2 and BAX was detected using immunohistochemistry. We found the following: Treatment with 2-BFI within 5 hours after reperfusion obviously improved neurological function. Administering 2-BFI within 9 hours after ischemia/reperfusion decreased infarct volume and alleviated apoptosis. 2-BFI administration at different time points after reperfusion alleviated the pathological damage of the ischemic penumbra and reduced the number of apoptotic neurons, but the protective effect was more obvious when administered within 5 hours. Administration of 2-BFI within 5 hours after reperfusion remarkably increased Bcl-2 expression and decreased BAX expression. To conclude, 2-BFI shows potent neuroprotective effects when administered within 5 hours after reperfusion, seemingly by up-regulating Bcl-2 and down-regulating BAX expression. The time window provided clinical potential for ischemic stroke by 2-BFI.

Host quality induces phenotypic plasticity in a wing polyphenic insect.

Food quality is a critical environmental condition that impacts an animal's growth and development. Many insects facing this challenge have evolved a phenotypically plastic, adaptive response. For example, many species of insect exhibit facultative wing growth, which reflects a physiological and evolutionary trade-off between dispersal and reproduction, triggered by environmental conditions. What the environmental cues are and how they are transduced to produce these alternative forms, and their associated ecological shift from dispersal to reproduction, remains an important unsolved problem in evolutionary ecology. In this study, we investigated the role that host quality has on the induction of wing development in a wing polyphenic insect exhibiting strong tradeoffs in investment between dispersal and reproduction, the brown planthopper, a serious rice pest in Asia. As rice plants grow, the short-winged brown planthopper dominates the population, but a shift occurs as the plants mature and senesce in the field such that long-winged brown planthoppers emerge and migrate. It remains unknown how changes in the rice plant induce development of the long-winged morph, despite recent discoveries on the role of the insulin and JNK signaling pathways in wing development. We found that by mimicking the glucose concentration of senescing rice plants, we significantly increased the proportion of long-winged female planthoppers. The effects of glucose on wing morph are additive with previously described effects of density. Our results show that host quality both directly regulates phenotypic plasticity and interacts with other factors such as density to produce the appropriate phenotype for specific environmental conditions.

Binding properties of four antennae-expressed chemosensory proteins (CSPs) with insecticides indicates the adaption of Spodoptera litura to environment.

Insects receive a variety of chemical signals from the environment. Chemosensory protein (CSP) is one of the olfactory proteins that can accommodate a variety of small molecules and have the ability to bind to lipophilic compounds, transmitting nonvolatile odor molecules and chemical stimuli to target cells. To understand the correlation between the insect olfactory system and environment, we identified four antennae-expressed SlituCSP genes and investigated their expression profiles after treatment with different temperatures, starvation and three commonly used pesticides: chlorpyrifos, emamectin benzoate and fipronil. The transcriptions of four SlituCSP genes are affected by pesticide treatment and less affected by starvation and different temperatures. To further understand the molecular function of CSPs and their correlation with pesticides, we expressed and purified four SlituCSPs and assayed their binding ability with pesticides. The binding of four SlituCSPs with three pesticides were determined using a fluorescence competitive binding assay. We found direct binding between CSPs and pesticides, especially between SlituCSP18 and chlorpyrifos/fipronil and between SlituCSP6 and all three pesticides. The high binding affinity with pesticides and the significant down-regulation of SlituCSP18 by chlorpyrifos suggests that SlituCSP18 is more sensitive to pesticide treatment and may play an important role in mediating the interaction of the olfactory system and the pesticide. This study can help us understand the role of CSP proteins in the adaption of S. litura to the environment.

Role of ABC transporters White, Scarlet and Brown in brown planthopper eye pigmentation.

The brown planthopper ATP-binding cassette (ABC) proteins White (W), Scarlet (St) and Brown (Bw) belong to the ABC transporter superfamily and are responsible for the transportation of guanine and tryptophan precursors of eye pigments. In the present study, the brown planthopper White (NlW), S t(NlSt) and Bw (NlBw) genes were cloned, and subsequent phylogenetic analysis showed that these genes are clustered with their respective homologues, with a genetic relationship observed between NlW and its Bemisia tabaci homologue having the highest similarity. Sequence alignments showed that these three proteins have a highly conserved Walker A domain, an ABC "signature sequence" and a Walker B domain. QRT-PCR demonstrated that W, St and Bw are highly expressed in the head of long-winged males and are highly expressed in both egg and male. Adult eye colour was altered after the downregulation of NlW, NlSt and NlBw in the 1st to 3rd instar nymph. The eye colours of emerged adults became white, dark and red after injection of dsNlW, dsNlSt and dsNlBw, respectively. The eye pigment content assay revealed that xanthommatin and pteridine were significantly decreased after the injection of dsRNAs, and the range of variation was inversely correlated with nymph age. The present study provides a theoretical basis for understanding the function of ABC transporters at the molecular and biochemical levels.

Endocrine regulation of a dispersal polymorphism in winged insects: a short review.

Changes in food availability and crowding are two critical environmental conditions that impact an animal's trajectory toward either reproduction or migration. Many insects facing this challenge have evolved wing polymorpisms that allow them to respond to changing conditions. When conditions favor reproduction, wing polymorphic species produce adults that either have no wings or short, non-functional wings; however, when conditions favor migration, adults with functional wings and robust flight muscles develop. Here we review three recently reported signaling pathways regulating wing polyphenism in wing polymorphic crickets, aphids, and brown planthoppers: juvenile horomone/ecdysone signaling, insulin signaling, and Jun-N-terminal Kinase (JNK) signaling. Understanding how these pathways respond to nutrition, stress and crowding with the appropriate adaptive phenotype is an important step in understanding how life-history trade-offs evolve.

2-(2-Benzofuranyl)-2-Imidazoline Mediates Neuroprotection by Regulating the Neurovascular Unit Integrity in a Rat Model of Focal Cerebral Ischemia.

BACKGROUND: We showed previously that 2-(2-benzofuranyl)-2-imidazoline (2-BFI), a ligand to type 2 imidazoline receptor (I2R) exerts neuroprotective effects in ischemia stroke via an unknown mechanism. The present study was to investigate whether 2-BFI can protect the neurovascular unit (NVU) using a rat model of 90 min focal cerebral ischemia. METHODS: Rats were randomly divided into three groups: thesham-operated group; the vehicle control group and the 2-BFI group which received 2-BFI (3 mg/kg) immediately after the start of middle cerebralartery occlusion (MCAO). Neurological deficit score, infarct size, apoptosis level, brain water content and Evans Blue extravasation were assessed at 24 h after stroke. Expressions of occludin and zonula occludens 1 (ZO-1), collagen IV, aquaporin-4 (AQP-4), matrix metalloproteinase-9 (MMP-9) and MMP-2 were assessed by Western blotting. RESULTS: 2-BFI treatment was associated with significant improvement of neurological performance and decreased infarct volume at 24 h after stroke. Apoptosis level reduced significantly by 2-BFI compared to the vehicle group (34.3 ± 5.4% vs 56.1 ± 7.9%, p < 0.05). Significant decreased of brain water content (79.5 ± 2.6% vs 84.62 ± 2%, p < 0.05) and Evans Blue extravasation (1.2 ± 0.5 vs 2.5 ± 0.41 µg/g, p < 0.05) of ipsilateral hemisphere was observed in 2-BFI group compared to vehicle group. Expressions of occludin, ZO-1 and collagen IV were significantly higher while MMP-9 level significantly lower in 2-BFI group. AQP-4 and MMP-2 showed no difference between 2-BFI and the vehicle groups. CONCLUSIONS: These results suggest that the neuroprotective effects of 2-BFI in acute ischemic brain damage are at least partly due to the drug's ability to improve the functions of NVU.

Role of Broad-Complex (Br) and Krüppel homolog 1 (Kr-h1) in the Ovary Development of Nilaparvata lugens.

Ovarian development plays an important role in the life history of insects and is crucial for control of the insect population. The metamorphosis of an insect is precisely regulated by the interaction of the juvenile hormone and ecdysone. To understand the role of NlBr and NlKr-h1 in ovary development, we used RNA interference (RNAi) to down-regulate the expression of Broad-Complex (Br) and Krüppel homolog 1 (Kr-h1), two important down-stream transcription factors of juvenile hormone and ecdysone signaling. We further investigated their effects on metamorphosis and ovary development. The results showed that both NlBr and NlKr-h1 are induced by ecdysone. The down-regulation of NlBr and NlKr-h1 alone or together by RNAi is more effective than the topical application of ecdysone on the number of ovarioles, suggesting the necessity of NlBr and NlKr-h1 in determining the number of ovarioles. The ovarian grade was significantly increased/decreased by the topical application of ecdysone and down-regulation of NlBr and NlKr-h1. The pre-oviposition period was also increased. When NlBr and NlKr-h1 were down-regulated together, the ovary grade was not significantly different compared to the control (dsGFP), indicating that the development of the ovary is under the control of both NlBr and NlKr-h1. The interaction between the NlBr and NlKr-h1 on the number of ovarioles and the development of the ovary indicates cross-talk between both juvenile hormone and ecdysone signaling at the transcription level in the brown planthopper. Both genes are nuclear transcription factors and may regulate signaling via down-stream genes. These results would help to both enhance the current understanding of the regulatory mechanism of the interaction between juvenile hormone and ecdysone signaling pathways during ovarian development and to design chemicals to control pests.

Characterization of Spodoptera litura (Lepidoptera: Noctuidae) Takeout Genes and Their Differential Responses to Insecticides and Sex Pheromone.

Spodoptera litura (S. litura) is one of the most serious agricultural insect pests worldwide. Takeout (TO) is involved in a variety of physiological and biochemical pathways and performs various biological functions. We characterized 18 S. litura TO genes and investigated their differential responses to insecticides and sex pheromones. All predicted TO proteins have two Cysteines that are unique to the N-terminal of the TO family proteins and contain four highly conserved Prolines, two Glycines, and one Tyrosine. The expression levels of seven TO genes in the male antennae were higher than those in the female antennae, although the expression levels of 10 TO genes in the female were higher than those in the male. We investigated the effects of the sex pheromone and three insecticides, that is, chlorpyrifos (Ch), emamectin benzoate (EB), and fipronil (Fi), on the expression levels of the TO genes in the antennae. The results showed that the insecticides and sex pheromone affect the expression levels of the TO genes. One day after the treatment, the expression levels of SlTO15 and SlTO4 were significantly induced by the Ch/EB treatment. Two days after the S. litura moths were treated with Fi, the expression of SlTO4 was significantly induced (28.35-fold). The expression of SlTO10 changed significantly after the Ch and EB treatment, although the expression of SlTO12 and SlTO15 was inhibited by the three insecticides after two days of treatment. Our results lay a foundation for studying the role of TO genes in the interaction between insecticides and sex pheromone.

Distinct Roles of Met and Interacting Proteins on the Expressions of takeout Family Genes in Brown Planthopper.

The takeout family genes encode relatively small proteins that are related to olfaction and are regulated by juvenile hormone (JH). The takeout genes modulate various physiological processes, such as behavioral plasticity in the migratory locust Locusta migraloria and feeding and courtship behaviors in Drosophila. Therefore, to understand the regulatory mechanism of these physiological processes, it is important to study the expressions of the takeout genes that are regulated by JH signaling. We used quantitative real-time PCR (qRTPCR) to study the role of JH signaling in the regulation of the takeout family genes in the brown planthopper Nilaparvata lugens (N. lugens) through the application of Juvenile hormone III (JHIII) and the down-regulation of key genes in the JH signaling pathway. The topical application of JHIII induced the expressions of most of the takeout family genes, and their expressions decreased 2 and 3 days after the JHIII application. Down-regulating the brown planthopper JH receptor NlMethoprene-tolerant (NlMet) and its interacting partners, NlTaiman (NlTai) and Nlß-Ftz-F1 (Nlß-Ftz), through RNAi, exhibited distinct effects on the expressions of the takeout family genes. The down-regulation of NlMet and NlKrüppel-homolog 1 (NlKr-h1) increased the expressions of the takeout family genes, while the down-regulation of the Met interacting partners NlTai and Nlß-Ftz decreased the expressions of most of the takeout family genes. This work advanced our understanding of the molecular function and the regulatory mechanism of JH signaling.

Ecological Trade-offs between Migration and Reproduction Are Mediated by the Nutrition-Sensitive Insulin-Signaling Pathway.

Crowding and changes in food availability are two critical environmental conditions that impact an animal's trajectory toward either migration or reproduction. Many insects facing this challenge have evolved wing polyphenisms. When conditions favor reproduction, wing polyphenic species produce adults that either have no wings or short, non-functional wings. Facultative wing growth reflects a physiological and evolutionary trade-off between migration and reproduction, triggered by environmental conditions. How environmental cues are transduced to produce these alternative forms, and their associated ecological shift from migration to reproduction, remains an important unsolved problem in evolutionary ecology. The brown planthopper, a wing polymorphic insect exhibiting strong trade-offs in investment between migration and reproduction, is one of the most serious rice pests in Asia. In this study, we investigated the function of four genes in the insulin-signaling pathway known to couple nutrition with growth, PI3 Kinase (PI3K), PDK1, Akt (Protein Kinase B), and the forkhead gene FOXO. Using a combination of RNA interference and pharmacological inhibitor treatment, we show that all four genes contribute to tissue level regulation of wing polymorphic development in this insect. As predicted, silencing of the NlPI3K, NlAkt and NlPDK1 through dsRNA and with the pharmacological inhibitor Perifosine resulted in short-winged brown planthoppers, whereas knockdown of NlFOXO resulted in long-winged planthoppers. Morphometric analyses confirm that phenotypes from our manipulations mimic what would be found in nature, i.e., major parameters such as bristle number, wing area and body weight are not significantly different from non-experimental animals. Taken together, these data implicate the insulin-signaling pathway in the transduction of environmental factors into condition-dependent patterns of wing growth in insects.