RESUMO
Throughout evolution, arboviruses have developed various strategies to counteract the host's innate immune defenses to maintain persistent transmission. Recent studies have shown that, in addition to bacteria and fungi, the innate Toll-Dorsal immune system also plays an essential role in preventing viral infections in invertebrates. However, whether the classical Toll immune pathway is involved in maintaining the homeostatic process to ensure the persistent and propagative transmission of arboviruses in insect vectors remain unclear. In this study, we revealed that the transcription factor Dorsal is actively involved in the antiviral defense of an insect vector (Laodelphax striatellus) by regulating the target gene, zinc finger protein 708 (LsZN708), which mediates downstream immune-related effectors against infection with the plant virus (Rice stripe virus, RSV). In contrast, an antidefense strategy involving the use of the nonstructural-protein (NS4) to antagonize host antiviral defense through competitive binding to Dorsal from the MSK2 kinase was employed by RSV; this competitive binding inhibited Dorsal phosphorylation and reduced the antiviral response of the host insect. Our study revealed the molecular mechanism through which Toll-Dorsal-ZN708 mediates the maintenance of an arbovirus homeostasis in insect vectors. Specifically, ZN708 is a newly documented zinc finger protein targeted by Dorsal that mediates the downstream antiviral response. This study will contribute to our understanding of the successful transmission and spread of arboviruses in plant or invertebrate hosts.
Assuntos
Arbovírus , Hemípteros , Oryza , Tenuivirus , Animais , Arbovírus/genética , Hemípteros/fisiologia , Tenuivirus/fisiologia , Insetos Vetores , Antivirais/metabolismo , Oryza/genética , Doenças das PlantasRESUMO
Communication between insects and plants relies on the exchange of bioactive molecules that traverse the species interface. Although proteinic effectors have been extensively studied, our knowledge of other molecules involved in this process remains limited. In this study, we investigate the role of salivary microRNAs (miRNAs) from the rice planthopper Nilaparvata lugens in suppressing plant immunity. A total of three miRNAs were confirmed to be secreted into host plants during insect feeding. Notably, the sequence-conserved miR-7-5P is specifically expressed in the salivary glands of N. lugens and is secreted into saliva, distinguishing it significantly from homologues found in other insects. Silencing miR-7-5P negatively affects N. lugens feeding on rice plants, but not on artificial diets. The impaired feeding performance of miR-7-5P-silenced insects can be rescued by transgenic plants overexpressing miR-7-5P. Through target prediction and experimental testing, we demonstrate that miR-7-5P targets multiple plant genes, including the immune-associated bZIP transcription factor 43 (OsbZIP43). Infestation of rice plants by miR-7-5P-silenced insects leads to the increased expression of OsbZIP43, while the presence of miR-7-5P counteracts this upregulation effect. Furthermore, overexpressing OsbZIP43 confers plant resistance against insects which can be subverted by miR-7-5P. Our findings suggest a mechanism by which herbivorous insects have evolved salivary miRNAs to suppress plant immunity, expanding our understanding of cross-kingdom RNA interference between interacting organisms.
Assuntos
Hemípteros , MicroRNAs , Oryza , Animais , Interferência de RNA , MicroRNAs/genética , MicroRNAs/metabolismo , Saliva , Hemípteros/fisiologia , Imunidade Vegetal/genética , Oryza/genéticaRESUMO
The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway is an evolutionarily conserved signaling pathway that can regulate various biological processes. However, the role of JAK-STAT pathway in the persistent viral infection in insect vectors has rarely been investigated. Here, using a system that comprised two different plant viruses, Rice stripe virus (RSV) and Rice black-streaked dwarf virus (RBSDV), as well as their insect vector small brown planthopper, we elucidated the regulatory mechanism of JAK-STAT pathway in persistent viral infection. Both RSV and RBSDV infection activated the JAK-STAT pathway and promoted the accumulation of suppressor of cytokine signaling 5 (SOCS5), an E3 ubiquitin ligase regulated by the transcription factor STAT5B. Interestingly, the virus-induced SOCS5 directly interacted with the anti-apoptotic B-cell lymphoma-2 (BCL2) to accelerate the BCL2 degradation through the 26S proteasome pathway. As a result, the activation of apoptosis facilitated persistent viral infection in their vector. Furthermore, STAT5B activation promoted virus amplification, whereas STAT5B suppression inhibited apoptosis and reduced virus accumulation. In summary, our results reveal that virus-induced JAK-STAT pathway regulates apoptosis to promote viral infection, and uncover a new regulatory mechanism of the JAK-STAT pathway in the persistent plant virus transmission by arthropod vectors.
Assuntos
Tenuivirus , Viroses , Animais , Janus Quinases/metabolismo , Transdução de Sinais , Fatores de Transcrição STAT/metabolismo , Tenuivirus/metabolismo , Insetos Vetores , Proteínas Proto-Oncogênicas c-bcl-2/metabolismoRESUMO
BACKGROUND: Saliva plays a crucial role in shaping the feeding behavior of insects, involving processes such as food digestion and the regulation of interactions between insects and their hosts. Cyrtorhinus lividipennis serves as a predominant natural enemy of rice pests, while Apolygus lucorum, exhibiting phytozoophagous feeding behavior, is a destructive agricultural pest. In this study, a comparative transcriptome analysis, incorporating the published genomes of C.lividipennis and A.lucorum, was conducted to reveal the role of salivary secretion in host adaptation. RESULTS: In contrast to A.lucorum, C.lividipennis is a zoophytophagous insect. A de novo genome analysis of C.lividipennis yielded 19,706 unigenes, including 16,217 annotated ones. On the other hand, A.lucorum had altogether 20,111 annotated genes, as obtained from the published official gene set (20,353 unigenes). Functional analysis of the top 1,000 salivary gland (SG)-abundant genes in both insects revealed that the SG was a dynamically active tissue engaged in protein synthesis and secretion. Predictions of other tissues and signal peptides were compared. As a result, 94 and 157 salivary proteins were identified in C.lividipennis and A.lucorum, respectively, and were categorized into 68 and 81 orthogroups. Among them, 26 orthogroups were shared, potentially playing common roles in digestion and detoxification, including several venom serine proteases. Furthermore, 42 and 55 orthogroups were exclusive in C.lividipennis and A.lucorum, respectively, which were exemplified by a hyaluronidase in C.lividipennis that was associated with predation, while polygalacturonases in A.lucorum were involved in mesophyll-feeding patterns. CONCLUSIONS: Findings in this study provide a comprehensive insight into saliva secretions in C.lividipennis and A.lucorum via a transcriptome approach, reflecting the intricate connections between saliva secretions and feeding behaviors. It is found that conserved salivary secretions are involved in shaping the overlapping feeding patterns, while a plethora of unique salivary secretions may drive the evolution of specific feeding behaviors crucial for their survival. These results enhance our understanding of the feeding mechanisms in different insects from the perspective of saliva and contribute to future environmentally friendly pest control by utilizing predatory insects.
Assuntos
Heterópteros , Transcriptoma , Animais , Heterópteros/genética , Glândulas Salivares , Perfilação da Expressão Gênica/métodos , SalivaRESUMO
Herbivorous insects such as whiteflies, planthoppers, and aphids secrete abundant orphan proteins to facilitate feeding. Yet, how these genes are recruited and evolve to mediate plant-insect interaction remains unknown. In this study, we report a horizontal gene transfer (HGT) event from fungi to an ancestor of Aleyrodidae insects approximately 42 to 190 million years ago. BtFTSP1 is a salivary protein that is secreted into host plants during Bemisia tabaci feeding. It targets a defensive ferredoxin 1 in Nicotiana tabacum (NtFD1) and disrupts the NtFD1-NtFD1 interaction in plant cytosol, leading to the degradation of NtFD1 in a ubiquitin-dependent manner. Silencing BtFTSP1 has negative effects on B. tabaci feeding while overexpressing BtFTSP1 in N. tabacum benefits insects and rescues the adverse effect caused by NtFD1 overexpression. The association between BtFTSP1 and NtFD1 is newly evolved after HGT, with the homologous FTSP in its fungal donor failing to interact and destabilize NtFD1. Our study illustrates the important roles of horizontally transferred genes in plant-insect interactions and suggests the potential origin of orphan salivary genes.
Assuntos
Afídeos , Hemípteros , Animais , Ferredoxinas/metabolismo , Plantas/metabolismo , Hemípteros/genética , Nicotiana/genética , Nicotiana/metabolismo , Afídeos/metabolismo , Proteínas e Peptídeos Salivares/genéticaRESUMO
BACKGROUND: As one of the components of visual photopigments in photoreceptor cells, opsin exhibits different spectral peaks and plays crucial roles in visual function. Besides, it is discovered to evolve other functions despite color vision. However, research on its unconventional function is limited nowadays. With the increase in genome database numbers, various numbers and types of opsins have been identified in insects due to gene duplications or losses. The Nilaparvata lugens (Hemiptera) is a rice pest known for its long-distance migration capability. In this study, opsins were identified in N. lugens and characterized by genome and transcriptome analyses. Meanwhile, RNA interference (RNAi) was carried out to investigate the functions of opsins, and then the Illumina Novaseq 6000 platform-based transcriptome sequencing was performed to reveal gene expression patterns. RESULTS: Four opsins belonging to G protein-coupled receptors were identified in the N. lugens genome, including one long-sensitive opsin (Nllw) together with two ultraviolet-sensitive opsins (NlUV1/2) and an additional new opsin with hypothesized UV peak sensitivity (NlUV3-like). A tandem array of NlUV1/2 on the chromosome suggested the presence of a gene duplication event, with similar exons distribution. Moreover, as revealed by spatiotemporal expression, the four opsins were highly expressed in eyes with age-different expression levels. Besides, RNAi targeting each of the four opsins did not significantly affect the survival of N. lugens in phytotron, but the silencing of Nllw resulted in the melanization of body color. Further transcriptome analysis revealed that silencing of Nllw resulted in up-regulation of a tyrosine hydroxylase gene (NlTH) and down-regulation of an arylalkylamine-N-acetyltransferases gene (NlaaNAT) in N. lugens, demonstrating that Nllw is involved in body color plastic development via the tyrosine-mediated melanism pathway. CONCLUSIONS: This study provides the first evidence in a Hemipteran insect that an opsin (Nllw) takes part in the regulation of cuticle melanization, confirming a cross-talk between the gene pathways underlying the visual system and the morphological differentiation in insects.
Assuntos
Hemípteros , Opsinas , Animais , Opsinas/genética , Genoma , Hemípteros/metabolismo , Transcriptoma , Perfilação da Expressão GênicaRESUMO
The spotted lanternfly (Lycorma delicatula) is an invasive pest that causes serious economic losses in fruit and wood production. Here, we identified a novel iflavirus named "Lycorma delicatula iflavirus 1" (LDIV1), in a spotted lanternfly. The full genome sequence of LDIV1 is 10,222 nt in length and encodes a polyprotein containing a picornavirus capsid-protein-domain-like domain, a cricket paralysis virus capsid superfamily domain, an RNA helicase domain, a peptidase C3 superfamily domain, and an RNA-dependent RNA polymerase (RdRp) domain. LDIV1 replicates in the host insect and activates small interfering RNA (siRNA)-based host antiviral immunity. Phylogenetic analysis demonstrated that LDIV1 is most closely related to an unspecified member of the order Picornavirales, with 61.7% sequence identity in the RdRp region and 57.6% sequence identity in the coat protein region, and thus meets the demarcation criteria for new species in the genus Iflavirus. To the best of our knowledge, LDIV1 is the first virus discovered in L. delicatula.
Assuntos
Hemípteros , Vírus de RNA , Animais , Filogenia , RNA Polimerase Dependente de RNA , Análise de Sequência de DNARESUMO
BACKGROUND: Host adaptation is the primary determinant of insect diversification. However, knowledge of different host ranges in closely related species remains scarce. The brown planthopper (Nilaparvata lugens, BPH) and the small brown planthopper (Laodelphax striatellus, SBPH) are the most destructive insect pests within the family Delphacidae. These two species differ in their host range (SBPH can well colonize rice and wheat plants, whereas BPH survives on only rice plants), but the underlying mechanism of this difference remains unknown. High-throughput sequencing provides a powerful approach for analyzing the association between changes in gene expression and the physiological responses of insects. Therefore, gut transcriptomes were performed to elucidate the genes associated with host adaptation in planthoppers. The comparative analysis of planthopper responses to different diets will improve our knowledge of host adaptation regarding herbivorous insects. RESULTS: In the present study, we analyzed the change in gene expression of SBPHs that were transferred from rice plants to wheat plants over the short term (rSBPH vs tSBPH) or were colonized on wheat plants over the long term (rSBPH vs wSBPH). The results showed that the majority of differentially expressed genes in SBPH showed similar changes in expression for short-term transfer and long-term colonization. Based on a comparative analysis of BPH and SBPH after transfer, the genes associated with sugar transporters and heat-shock proteins showed similar variation. However, most of the genes were differentially regulated between the two species. The detoxification-related genes were upregulated in SBPH after transfer from the rice plants to the wheat plants, but these genes were downregulated in BPH under the same conditions. In contrast, ribosomal-related genes were downregulated in SBPH after transfer, but these genes were upregulated in BPH under the same conditions. CONCLUSIONS: The results of this study provide evidence that host plants played a dominant role in shaping gene expression and that the low fitness of BPH on wheat plants might be determined within 24 h after transfer. This study deepens our understanding of different host ranges for the two planthopper species, which may provide a potential strategy for pest management.
Assuntos
Hemípteros , Oryza , Animais , Dieta , Hemípteros/genética , Especificidade de Hospedeiro , Oryza/genética , Transcriptoma , TriticumRESUMO
The spider mite Tetranychus evansi has a remarkable ability to suppress and manipulate plant defenses, which makes it an ideal model to investigate plant-herbivores interactions. In this study, a de novo assembly of the transcriptome of T. evansi is performed and the proteins in its secreted saliva by LC-MS/MS are characterized. A total of 29 365 unigenes are assembled and 136 saliva proteins are identified. Comparative analysis of the saliva proteins in T. evansi, T. truncatus, and T. urticae shows that 64 protein groups are shared by at least two Tetranychus species, and 52 protein groups are specifically identified in T. evansi. In addition, some saliva proteins are common in arthropod species, while others are species-specific. These results will help to elucidate the molecular mechanisms by which T. evansi modulates plant defenses.
Assuntos
Saliva/química , Proteínas e Peptídeos Salivares/química , Tetranychidae/química , Transcriptoma , Animais , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas em TandemRESUMO
Extracellular DNA, released by damaged plant cells, acts as a damage-associated molecular pattern (DAMP). We demonstrated previously that the small brown planthopper (Laodelphax striatellus, SBPH) secreted DNase II when feeding on artificial diets. However, the function of DNase II in insect feeding remained elusive. The influences of DNase II on SBPHs and rice plants were investigated by suppressing expression of DNase II or by application of heterogeneously expressed DNase II. We demonstrated that DNase II is mainly expressed in the salivary gland and is responsible for DNA-degrading activity of saliva. Knocking down the expression of DNase II resulted in decreased performance of SBPH reared on rice plants. The dsDNase II-treated SBPH did not influenced jasmonic acid (JA), salicylic acid (SA), ethylene (ET) pathways, but elicited a higher level of H2 O2 and callose accumulation. Application of heterogeneously expressed DNase II in DNase II-deficient saliva slightly reduced the wound-induced defence response. We propose a DNase II-based invading model for SBPH feeding on host plants, and provide a potential target for pest management.
Assuntos
Endodesoxirribonucleases/metabolismo , Hemípteros/enzimologia , Nicotiana/metabolismo , Oryza/metabolismo , Sequência de Aminoácidos , Animais , Líquidos Corporais/química , Endodesoxirribonucleases/química , Endodesoxirribonucleases/genética , Regulação Enzimológica da Expressão Gênica , Glucanos/metabolismo , Peróxido de Hidrogênio/metabolismo , Interferência de RNA , Nicotiana/efeitos dos fármacosRESUMO
While it has been proposed in several taxa that the mitochondrial genome is associated with adaptive evolution to different climatic conditions, making links between mitochondrial haplotypes and organismal phenotypes remains a challenge. Mitonuclear discordance occurs in the small brown planthopper (SBPH), Laodelphax striatellus, with one mitochondrial haplogroup (HGI) more common in the cold climate region of China relative to another form (HGII) despite strong nuclear gene flow, providing a promising model to investigate climatic adaptation of mitochondrial genomes. We hypothesized that cold adaptation through HGI may be involved, and considered mitogenome evolution, population genetic analyses, and bioassays to test this hypothesis. In contrast to our hypothesis, chill-coma recovery tests and population genetic tests of selection both pointed to HGII being involved in cold adaptation. Phylogenetic analyses revealed that HGII is nested within HGI, and has three nonsynonymous changes in ND2, ND5 and CYTB in comparison to HGI. These molecular changes likely increased mtDNA copy number, cold tolerance and fecundity of SBPH, particularly through a function-altering amino acid change involving M114T in ND2. Nuclear background also influenced fecundity and chill recovery (i.e., mitonuclear epistasis) and protein modelling indicates possible nuclear interactions for the two nonsynonymous changes in ND2 and CYTB. The high occurrence frequency of HGI in the cold climate region of China remains unexplained, but several possible reasons are discussed. Overall, our study points to a link between mtDNA variation and organismal-level evolution and suggests a possible role of mitonuclear interactions in maintaining mtDNA diversity.
Assuntos
Evolução Molecular , Hemípteros/genética , Mitocôndrias/genética , Característica Quantitativa Herdável , Adaptação Fisiológica/genética , Animais , Tamanho Corporal/genética , DNA Mitocondrial/genética , Feminino , Fertilidade/genética , Amplificação de Genes , Genética Populacional , Genoma Mitocondrial , Geografia , Haplótipos/genética , Masculino , Filogenia , Homologia Estrutural de Proteína , TemperaturaRESUMO
Planthoppers are highly destructive pests that damage rice plants by feeding and transmitting viruses. They feed on phloem sap using specialized mouthparts and secrete saliva during feeding. Over the past decade, genomic, transcriptomic, and proteomic approaches have greatly improved our understanding of the complexity of planthopper saliva, and have provided a glimpse of planthopper-plant interactions. Here we focus on a few recent advances in planthopper saliva and discuss how salivary components influence planthopper performance. Understanding the molecular basis of saliva in planthopper-plant interactions will provide evolutionary insights, and promote the development of novel strategies for controlling agricultural pests.
Assuntos
Líquidos Corporais/fisiologia , Regulação da Expressão Gênica/fisiologia , Hemípteros/fisiologia , Proteínas de Insetos , Animais , Interações Hospedeiro-Parasita , Poaceae/parasitologiaRESUMO
The brown planthopper (Nilaparvata lugens, BPH), white-backed planthopper (Sogatella furcifera, WBPH) and small brown planthopper (Laodelphax striatellus, SBPH) are important rice pests in Asia. These three species differ in thermal tolerance and exhibit quite different migration and overwintering strategies. To understand the underlying mechanisms, we sequenced and compared the transcriptome of the three species under different temperature treatments. We found that metabolism-, exoskeleton- and chemosensory-related genes were modulated. In high temperature (37 °C), heat shock protein (HSP) genes were the most co-regulated; other genes related with fatty acid metabolism, amino acid metabolism and transportation were also differentially expressed. In low temperature (5 °C), the differences in gene expression of the genes for fatty acid synthesis, transport proteins and cytochrome P450 might explain why SBPH can overwinter in high latitudes, while BPH and WBPH cannot. In addition, other genes related with moulting, and membrane lipid composition might also play roles in resistance to low and high temperatures. Our study illustrates the common responses and different tolerance mechanisms of three rice planthoppers in coping with temperature change, and provides a potential strategy for pest management.
Assuntos
Genes de Insetos , Hemípteros/genética , Temperatura , Aclimatação/genética , Animais , Ásia , Regulação da Expressão Gênica , Hemípteros/classificação , OryzaRESUMO
Most phloem-feeding insects secrete gelling and watery saliva during the feeding process. However, the functions of salivary proteins are poorly understood. In this study, our purpose was to reveal the components and functions of saliva in a rice sap-sucking insect pest, Nilaparvata lugens. The accomplishment of the whole genome and transcriptome sequencing in N. lugens would be helpful for elucidating the gene information and expression specificity of the salivary proteins. In this study, we have, for the first time, identified the abundant protein components from gelling and watery saliva in a monophagous sap-sucking insect species through shotgun proteomic detection combined with the genomic and transcriptomic analysis. Eight unknown secreted proteins were limited to N. lugens, indicating species-specific saliva components. A group of annexin-like proteins first identified in the secreted saliva displayed different domain structure and expression specificity with typical insect annexins. Nineteen genes encoding five annexin-like proteins, six salivaps (salivary glands-specific proteins with unknown function), seven putative enzymes, and a mucin-like protein showed salivary gland-specific expression pattern, suggesting their importance in the physiological mechanisms of salivary gland and saliva in this insect species. RNA interference revealed that salivap-3 is a key protein factor in forming the salivary sheath, while annexin-like5 and carbonic anhydrase are indispensable for N. lugens survival. These novel findings will greatly help to clarify the detailed functions of salivary proteins in the physiological process of N. lugens and elucidate the interaction mechanisms between N. lugens and the rice plant, which could provide important targets for the future management of rice pests.
Assuntos
Hemípteros/química , Proteoma/análise , Saliva/química , Proteínas e Peptídeos Salivares/análise , Animais , Perfilação da Expressão Gênica , Genômica , Proteínas de Insetos/análise , Oryza , Proteômica , Glândulas Salivares/química , Especificidade da EspécieRESUMO
The cytochrome P450 monooxygenase (P450) gene family is one of the most abundant eukaryotic gene families that encode detoxification enzymes. In this study, we identified an abundance of P450 gene repertoire through genome- and transcriptome-wide analysis in the brown planthopper (Nilaparvata lugens), the most destructive rice pest in Asia. Detailed gene information including the exon-intron organization, size, transcription orientation and distribution in the genome revealed that many P450 loci were closely situated on the same scaffold, indicating frequent occurrence of gene duplications. Insecticide-response expression profiling revealed that imidacloprid significantly increased NlCYP6CS1v2, NLCYP4CE1v2, NlCYP4DE1, NlCYP417A1v2 and NlCYP439A1 expression; while triazophos and deltamethrin notably enhanced NlCYP303A1 expression. Expression analysis at the developmental stage showed the egg-, nymph-, male- and female-specific expression patterns of N. lugens P450 genes. These novel findings will be helpful for clarifying the P450 functions in physiological processes including development, reproduction and insecticide resistance in this insect species.
Assuntos
Sistema Enzimático do Citocromo P-450/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Hemípteros/enzimologia , Inseticidas/farmacologia , Animais , Sistema Enzimático do Citocromo P-450/efeitos dos fármacos , Feminino , Genes de Insetos , Genômica , Hemípteros/efeitos dos fármacos , Hemípteros/genética , Imidazóis/farmacologia , Masculino , Neonicotinoides , Nitrilas/farmacologia , Nitrocompostos/farmacologia , Ninfa/enzimologia , Ninfa/genética , Organotiofosfatos/farmacologia , Piretrinas/farmacologia , Triazóis/farmacologiaRESUMO
Saliva, an oral secretion primarily originating from salivary glands (SGs), exert critical roles in the ongoing evolutionary interaction between insects and plants. However, identifying insect salivary components poses challenges due to the tiny size of insects, low secretion amounts, and the propensity for degradation after secretion. In this study, we developed a transcriptome-based approach to comprehensively analyze the salivary proteins of the short-headed planthopper, Epeurysa nawaii, a species with unique feeding habits on bamboo. A total of 165 salivary proteins were identified, with 114 secretory genes highly and specifically expressed in SGs. Consistent with most phloem-feeding insects, digestive enzymes, calcium-binding proteins, oxidoreductases, and a few previously reported salivary effectors were ubiquitously distributed in E. nawaii saliva. However, we also identified a substantial portion of salivary proteins exhibiting taxonomy specificity, including 60 E. nawaii-specific and 62 Delphacidae-specific proteins. These taxonomy-restricted proteins potentially play a role in insect adaptation to specific host plants. Our study provides an efficient pipeline for salivary protein identification and serves as a valuable resource for the functional characterization of effectors.
Assuntos
Hemípteros , Glândulas Salivares , Animais , Glândulas Salivares/metabolismo , Saliva/metabolismo , Hemípteros/metabolismo , Transcriptoma , Proteínas e Peptídeos Salivares/metabolismo , Proteínas de Insetos/metabolismoRESUMO
Herbivorous insects employ an array of salivary proteins to aid feeding. However, the mechanisms behind the recruitment and evolution of these genes to mediate plant-insect interactions remain poorly understood. Here, we report a potential horizontal gene transfer (HGT) event from bacteria to an ancestral bug of Eutrichophora. The acquired genes subsequently underwent duplications and evolved through co-option. We annotated them as horizontal-transferred, Eutrichophora-specific salivary protein (HESPs) according to their origin and function. In Riptortus pedestris (Coreoidea), all nine HESPs are secreted into plants during feeding. The RpHESP4 to RpHESP8 are recently duplicated and found to be indispensable for salivary sheath formation. Silencing of RpHESP4-8 increases the difficulty of R. pedestris in probing the soybean, and the treated insects display a decreased survivability. Although silencing the other RpHESPs does not affect the salivary sheath formation, negative effects are also observed. In Pyrrhocoris apterus (Pyrrhocoroidea), five out of six PaHESPs are secretory salivary proteins, with PaHESP3 being critical for insect survival. The PaHESP5, while important for insects, no longer functions as a salivary protein. Our results provide insight into the potential origin of insect saliva and shed light on the evolution of salivary proteins.
Assuntos
Transferência Genética Horizontal , Heterópteros , Animais , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Heterópteros/genética , Heterópteros/metabolismo , Proteínas e Peptídeos Salivares/genética , Proteínas e Peptídeos Salivares/metabolismoRESUMO
Many insect pests, including the brown planthopper (BPH), undergo windborne migration that is challenging to observe and track. It remains controversial about their migration patterns and largely unknown regarding the underlying genetic basis. By analyzing 360 whole genomes from around the globe, we clarify the genetic sources of worldwide BPHs and illuminate a landscape of BPH migration showing that East Asian populations perform closed-circuit journeys between Indochina and the Far East, while populations of Malay Archipelago and South Asia undergo one-way migration to Indochina. We further find round-trip migration accelerates population differentiation, with highly diverged regions enriching in a gene desert chromosome that is simultaneously the speciation hotspot between BPH and related species. This study not only shows the power of applying genomic approaches to demystify the migration in windborne migrants but also enhances our understanding of how seasonal movements affect speciation and evolution in insects.
Assuntos
Migração Animal , Genômica , Vento , Animais , Genômica/métodos , Hemípteros/genética , Genoma de Inseto , Genética PopulacionalRESUMO
Planthoppers possess an impressive ability to exhibit phenotypic plasticity, which allows them to adjust their morphology for migration, overwintering, and adaptation to different environmental conditions. The wing and color polyphenism are the two most outward morphologies. Wing polyphenism serves as a classic illustration of a life history trade-off between reproduction and migration, while color polyphenism is potentially correlated with the insect development and immunity. In this review, we present the important contributions that link environment cues to wing and color polyphenism, and highlight recent advances in insulin/insulin-like growth factor signaling-forkhead transcription factor subgroup O (FoxO) pathway-mediated wing development and tyrosine-melanin pathway-mediated coloration. Further work, particularly in the identification of the genes that FoxO regulates and in the elucidation of the intracellular signals that link the stimuli to the tyrosine-melanin pathway, is required.
RESUMO
The bean bug, Riptortus pedestris (Hemiptera: Heteroptera), poses a significant threat to soybean production, resulting in substantial crop losses. Throughout the soybean cultivation period, these insects probe and suck on various parts of plants, including leaves, pods, and beans. However, the specific mechanisms by which they adapt to different food resources remain unknown. In this study, we conducted gut transcriptomic analyses of R. pedestris fed with soybean leaves, pods, and beans. A total of 798, 690, and 548 differently expressed genes (DEGs) were monitored in G-pod vs. G-leaf (comparison of insect feeding on pods and leaves), G-bean vs. G-leaf (comparison of insect feeding on beans and leaves), and G-pod vs. G-bean (comparison of insect feeding on pods and beans), respectively. When fed on pods and beans, there was a significant increase in the expression of digestive enzymes, particularly cathepsins, serine proteases, and lipases. Conversely, when soybean leaves were consumed, detoxification enzymes, such as ABC transporters and 4-coumarate-CoA ligase, exhibited higher expression. Our findings indicate that R. pedestris dynamically regulates different metabolic pathways to cope with varying food resources, which may contribute to the development of effective strategies for managing this pest.