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1.
Chemosphere ; 249: 126463, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32213388

RESUMO

The brown planthopper (BPH), Nilaparvata lugens, is a resurgent pest with an unexpected response to jinggangmycin (JGM), a broadly applied antibiotic used to control rice sheath blight disease. JGM stimulates BPH fecundity, but the underlining molecular mechanisms remain unclear. Here we report that JGM sprays led to increased glucose concentrations, photosynthesis and gene expression, specifically Rubsico, sucrose phosphate synthase, invertase 2 (INV2) and INV3 in rice plants. JGM sprays led to high-glucose rice plants. Feeding BPH on these plants led to increased insulin-like signaling and vitellogenin synthesis. Treating BPH with metformin, a gluconeogenesis inhibitor, reversed the influence of feeding on high-glucose rice, which was rescued by glucose injections. Silencing insulin-like peptide 2 using per os dsRNA led to reduction in juvenile hormone (JH) III titers and other fecundity parameters, which were reversed by topical applications of the JH analog, methoprene. We infer that JGM acts via two broad mechanisms, one through increasing rice plant sugar concentrations and a second by upregulating BPH insulin-like signaling.


Assuntos
Antibacterianos/farmacologia , Hemípteros/fisiologia , Inositol/análogos & derivados , Oryza/metabolismo , Animais , Fertilidade/efeitos dos fármacos , Inositol/farmacologia , Insulina/metabolismo , RNA de Cadeia Dupla , Açúcares/metabolismo
2.
J Agric Food Chem ; 68(8): 2539-2546, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32023056

RESUMO

The rice planthopper is a very important hemipteran pest that preys on rice and substantially affects the safety of rice production. Moreover, the long-term prevention and control of these pests with chemical pesticides has led to an increase in the resistance of the rice planthopper as well as serious environmental pollution and food safety problems. Bacillus thuringiensis (Bt) has been used for the efficient and green control of a variety of rice pests. Therefore, based on the high-throughput screening of Bt strains that are active against the rice planthopper, we found that Bt strain B4F11 showed certain insecticidal activity against Laodelphax striatellus Fallén, and we have identified a novel insecticidal protein Cry78Ba1 from the Bt strain B4F11, which is expected to provide the specific and safe control of the rice planthopper. The Cry78Ba1 protein is composed of 380 amino acid residues with a molecular weight of 42.55 kDa and contains conserved Ricin_B_Lectin and Toxin_10 superfamily domains. It displays high insecticidal activity against L. striatellus with a lethal concentration (LC50) of 9.723 µg/mL. More importantly, this Toxin_10-like protein does not display sequence homology to any known allergen and can be degraded and inactivated rapidly when heated at 90 °C and in simulated gastrointestinal fluid. In summary, Cry78Ba1 has great potential for applications in the efficient and safe prevention and control of the rice planthopper.


Assuntos
Bacillus thuringiensis/genética , Proteínas de Bactérias/toxicidade , Endotoxinas/toxicidade , Hemípteros/efeitos dos fármacos , Proteínas Hemolisinas/toxicidade , Inseticidas/toxicidade , Animais , Bacillus thuringiensis/química , Bacillus thuringiensis/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Endotoxinas/genética , Endotoxinas/metabolismo , Hemípteros/fisiologia , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/metabolismo , Inseticidas/metabolismo , Oryza/parasitologia , Controle Biológico de Vetores/métodos , Doenças das Plantas/parasitologia
3.
J Insect Sci ; 20(1)2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32061084

RESUMO

The vanilloid-type transient receptor potential (TRPV) channel is reported to be the molecular target of the commercial insecticide pymetrozine, which specifically disrupts the feeding of plant sap-sucking insects. However, the functions of TRPV channels in plant sap-sucking insects have not been fully elucidated. In the present study, RNA interference was used to investigate the effects of the knockdown of TRPV genes (Nan and Iav) on the mortality, locomotion, and feeding behavior of an important plant-feeding insect pest in rice, the brown planthopper, Nilaparvata lugens. Injecting dsRNA of Nan and Iav into fourth-instar nymphs significantly knocked down the target genes. The injection of dsNan or dsIav did not affect any morphological phenotype (including leg extension) of N. lugens nymphs and adults. Knockdown of Nan or Iav resulted in significantly decreased climbing activity against top plants but did not influence the leg-griping strength of adults. Knockdown of Nan resulted in a significantly elevated mortality of N. lugens in the observation period of 7 d after injection, whereas no significant difference in survival rates 7 d after injection was found between dsIav-injected and dsGFP-injected insects. Electropenetrographic (EPG) recordings indicated that knockdown of Nan and Iav reduced the ingestion activity in the rice phloem tissues of N. lugens. Knockdown of Nan and Iav significantly reduced the amount of honeydew excreted by N. lugens. Our findings indicated a relationship between TRPV and N. lugens locomotion and feeding behavior, which may help to fully elucidate the functions of TRPV in insects.


Assuntos
Hemípteros/genética , Canais de Cátion TRPV/genética , Animais , Comportamento Alimentar , Hemípteros/fisiologia , Locomoção/genética , Ninfa/genética , Ninfa/fisiologia , Oryza , Floema , Interferência de RNA , Canais de Cátion TRPV/metabolismo
4.
Zoolog Sci ; 37(1): 42-49, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32068373

RESUMO

For seasonal adaptation, the brown-winged green bug Plautia stali (Hemiptera: Pentatomidae) enters reproductive diapause by suppressing juvenile hormone biosynthesis. Plautia stali myoinhibitory peptides (Plast-MIPs) are known to have allatostatic effects and to suppress juvenile hormone biosynthesis. We examined Plast-MIP-producing neurons in the brain with immunohistochemistry and Fourier transform ion cyclotron resonance mass spectrometry. Rabbit polyclonal antiserum against Plast-MIP revealed immunoreactive cells in seven regions of the brain, including the posterior antennal lobe, basal optic lobe, dorsal anterior protocerebrum, ventrolateral protocerebrum, pars intercerebralis, posterior protocerebrum, and dorsal posterior region to the calyx of the mushroom body, aside from the gnathal ganglion. Anatomical locations of the immunoreactive cells in the pars intercerebralis and dorsal posterior region to the mushroom body calyx partly overlapped with the cell body location stained by retrograde dye fills from the corpus allatum and corpus cardiacum complex. Direct mass spectrometry revealed the molecular ion peaks corresponding to the predictive mass of Plast-MIPs in the pars intercerebralis and the corpus allatum-corpus cardiacum complex. Plast-MIP immunoreactivity in different cell types suggests that Plast-MIPs have different functions in the cephalic ganglia. Considering the anatomical location of neurons projecting to the corpus allatum-corpus cardiacum and results of mass spectrometry, Plast-MIP immunoreactive cells in the pars intercerebralis may play a role in suppressing juvenile hormone biosynthesis.


Assuntos
Encéfalo/metabolismo , Hemípteros/fisiologia , Proteínas de Insetos/metabolismo , Neuropeptídeos/metabolismo , Animais , Diapausa de Inseto/fisiologia , Feminino , Hemípteros/metabolismo , Imuno-Histoquímica , Hormônios Juvenis/biossíntese , Neurônios/metabolismo
5.
Arch Virol ; 165(1): 169-178, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31773326

RESUMO

Plant viruses can alter the behavior or performance of their arthropod vectors, either indirectly (through effects of virus infection on the host plant) or directly (from virus acquisition by the vector). Given the diversity of plant viruses and their arthropod vectors, the effects for any specific system are not possible to predict. Here, we present experimental evidence that acquisition of maize Iranian mosaic virus (MIMV, genus Nucleorhabdovirus, family Rhabdoviridae) modifies the biological traits of its insect vector, the small brown planthopper (SBPH) Laodelphax striatellus. MIMV is an economically important virus of maize and several other grass species. It is transmitted by SBPHs in a persistent-propagative manner. We evaluated the effects of MIMV acquisition by SBPH on its life history when reared on healthy barley plants (Hordeum vulgare). We conclude that 1) MIMV acquisition by SBPHs increases female fecundity, duration of the nymph stage, adult longevity, and survival of SBPHs, (2) the mortality rate and female-to-male sex ratio are reduced in MIMV-infected planthoppers, and (3) MIMV infection increases the concentration of some biochemical components of the infected plants, including carbohydrates, some amino acids, and total protein, which might influence the life traits of its insect vector. The results indicate the potential of MIMV to improve the ecological fitness of its vector, SBPH, through direct or indirect effects, with the potential to increase the spread of the virus.


Assuntos
Hemípteros/fisiologia , Rhabdoviridae/fisiologia , Zea mays/metabolismo , Zea mays/virologia , Aminoácidos/metabolismo , Animais , Metabolismo dos Carboidratos , Feminino , Fertilidade , Hemípteros/virologia , Insetos Vetores/fisiologia , Insetos Vetores/virologia , Longevidade , Masculino , Proteínas de Plantas/metabolismo , Vírus de Plantas/fisiologia
6.
Insect Sci ; 27(1): 58-68, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29676854

RESUMO

"Candidatus Liberibacter solanacearum" (Lso) are phloem-restricted and unculturable Gram-negative bacteria. Presently five haplotypes have been identified worldwide; but only haplotypes A and B are associated with the vector Bactericera cockerelli (Sulc.) in the Americas. Previous studies showed that Lso-infection reduces B. cockerelli reproductive output and that Lso haplotype B is more pathogenic than Lso haplotype A. To understand the interaction of Lso haplotype B and B. cockerelli, the fitness of Lso-free and Lso B-infected insects, and the expression of vitellogenin (BcVg1-like), a gene involved directly in the insect reproduction were analyzed. Statistical differences in the number of eggs oviposited, and the total number of progeny nymphs and adults were found among crosses of insects with or without Lso. Significant differences in sex proportions were found between Lso B-infected and Lso-free crosses: a higher proportion of F1 adult females were obtained from Lso B-infected mothers. A significant reduction of BcVg1-like was observed in crosses performed with Lso B-infected females compared to the Lso-free insects. In female cohorts of different age, a significant reduction of BcVg1-like expression was measured in 7-d-old Lso B-infected females (virgin and mated) compared with 7-d-old Lso-free females (virgin and mated), respectively. The reduction of BcVg1-like transcript was associated with a lower number of developing oocytes observed in female's reproductive systems. Overall, this study represents the first step to understand the interaction of Lso B with B. cockerelli, highlighting the effect of Lso B infection on egg production, BcVg1-like expression, and oocyte development.


Assuntos
Aptidão Genética , Hemípteros/fisiologia , Rhizobiaceae/fisiologia , Vitelogênese , Animais , Hemípteros/genética , Hemípteros/crescimento & desenvolvimento , Hemípteros/microbiologia , Lycopersicon esculentum/microbiologia , Lycopersicon esculentum/fisiologia , Ninfa/genética , Ninfa/crescimento & desenvolvimento , Ninfa/microbiologia , Ninfa/fisiologia , Doenças das Plantas/microbiologia
7.
Insect Sci ; 27(1): 49-57, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29999564

RESUMO

In agro-ecosystems, plants are important mediators of interactions between their associated herbivorous insects and microbes, and any change in plants induced by one species may lead to cascading effects on interactions with other species. Often, such effects are regulated by phytohormones such as jasmonic acid (JA) and salicylic acid (SA). Here, we investigated the tripartite interactions among rice plants, three insect herbivores (Chilo suppressalis, Cnaphalocrocis medinalis or Nilaparvata lugens), and the causal agent of rice blast disease, the fungus Magnaporthe oryzae. We found that pre-infestation of rice by C. suppressalis or N. lugens but not by C. medinalis conferred resistance to M. oryzae. For C. suppressalis and N. lugens, insect infestation without fungal inoculation induced the accumulation of both JA and SA in rice leaves. In contrast, infestation by C. medinalis increased JA levels but reduced SA levels. The exogenous application of SA but not of JA conferred resistance against M. oryzae. These results suggest that pre-infestation by C. suppressalis or N. lugens conferred resistance against M. oryzae by increasing SA accumulation. These findings enhance our understanding of the interactions among rice plant, insects and pathogens, and provide valuable information for developing an ecologically sound strategy for controlling rice blast.


Assuntos
Hemípteros/fisiologia , Herbivoria , Magnaporthe/fisiologia , Mariposas/fisiologia , Oryza/microbiologia , Doenças das Plantas/microbiologia , Ácido Salicílico/metabolismo , Animais , Resistência à Doença/fisiologia
8.
BMC Plant Biol ; 19(1): 556, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31842757

RESUMO

BACKGROUND: While virus-vector-host interactions have been a major focus of both basic and applied ecological research, little is known about how different levels of plant defense interact with prior herbivory to affect these relationships. We used genetically-modified strains of tomato (Solanum lycopersicum) varying in the jasmonic acid (JA) plant defense pathways to explore how plant defense and prior herbivory affects a plant virus (tomato yellow leaf curl virus, 'TYLCV'), its vector (the whitefly Bemisia tabaci MED), and the host. RESULTS: Virus-free MED preferred low-JA over high-JA plants and had lower fitness on high-JA plants. Viruliferous MED preferred low-JA plants but their survival was unaffected by JA levels. While virus-free MED did not lower plant JA levels, viruliferous MED decreased both JA levels and the expression of JA-related genes. Infestation by viruliferous MED reduced plant JA levels. In preference tests, neither virus-free nor viruliferous MED discriminated among JA-varying plants previously exposed to virus-free MED. However, both virus-free and viruliferous MED preferred low-JA plant genotypes when choosing between plants that had both been previously exposed to viruliferous MED. The enhanced preference for low-JA genotypes appears linked to the volatile compound neophytadiene, which was found only in whitefly-infested plants and at concentrations inversely related to plant JA levels. CONCLUSIONS: Our findings illustrate how plant defense can interact with prior herbivory to affect both a plant virus and its whitefly vector, and confirm the induction of neophytadiene by MED. The apparent attraction of MED to neophytadiene may prove useful in pest detection and management.


Assuntos
Antibiose , Begomovirus/fisiologia , Ciclopentanos/metabolismo , Hemípteros/fisiologia , Herbivoria , Lycopersicon esculentum/fisiologia , Oxilipinas/metabolismo , Doenças das Plantas/virologia , Animais , Lycopersicon esculentum/imunologia , Lycopersicon esculentum/virologia , Imunidade Vegetal , Plantas Geneticamente Modificadas/imunologia , Plantas Geneticamente Modificadas/fisiologia , Plantas Geneticamente Modificadas/virologia , Transdução de Sinais
9.
J Chem Ecol ; 45(11-12): 934-945, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31755021

RESUMO

The African citrus triozid, Trioza erytreae Del Guercio (Hemiptera: Triozidae) is one of the primary vectors of the bacterium Candidatus Liberibacter spp. which causes citrus greening, a disease of global economic importance in citrus production. Despite its economic importance, little is known about its chemical ecology. Here, we used behavioral assays and chemical analysis to study the chemical basis of interaction between T. erytreae and one of its preferred host plants, Citrus jambhiri. In dual choice Y-tube olfactometer assays, lemon leaf odors attracted females but not males compared to plain air or solvent controls. However, in a petri dish arena assay, both sexes were arrested by lemon leaf odors. Coupled gas chromatography-mass spectrometry (GC/MS) analysis revealed quantitative differences in the odors of flushing and mature leaves, dominated by terpenes. Twenty-six terpenes were identified and quantified. In Petri dish arena assays, synthetic blends of the most abundant terpenes mimicking lemon flushing leaf odors elicited varying behavioral responses from both sexes of T. erytreae. A nine-component blend and a blend of the three most abundant terpenes; limonene, sabinene and ß-ocimene arrested both sexes of T. erytreae. In contrast, a six-component blend lacking in these three components elicited an avoidance response in both sexes. Furthermore, both sexes of T. erytreae preferred the three-component synthetic blend to lemon crude volatile extract. These results suggest that lemon terpenes might be used in the management of T. erytreae.


Assuntos
Citrus/química , Hemípteros/fisiologia , Extratos Vegetais/química , Terpenos/química , Compostos Orgânicos Voláteis/química , Animais , Comportamento Animal , Citrus/parasitologia , Feminino , Cromatografia Gasosa-Espectrometria de Massas/métodos , Especificidade de Hospedeiro , Interações Hospedeiro-Parasita , Insetos Vetores , Masculino , Odorantes , Doenças das Plantas/microbiologia , Extratos Vegetais/metabolismo , Folhas de Planta/química , Folhas de Planta/metabolismo , Terpenos/metabolismo , Compostos Orgânicos Voláteis/metabolismo
10.
An Acad Bras Cienc ; 91(3): e20180597, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31618410

RESUMO

Several parasitoids attacking the same host may lead to competition. Adult parasitoids' abilities to find, parasitize and defend hosts determine resource's retention potential. In soybean, two egg parasitoid species, Telenomus podisi and Trissolcus urichi (Hymenoptera: Platygastridae), compete on the egg masses of Piezodorus guildinii (Hemiptera: Pentatomidae) one of the major pest of this crop. We evaluated parasitoid's abilities to exploit hosts' footprints; and parasitoid's behavior when competing for the same host. Both arena residence time and retention time were similar for T. podisi and T. urichi on male or female host footprints. In its turn, T. urichi reentered the area contaminated with P. guildinii more times and staid longer in it than T. podisi. Furthermore, when competing for the same egg mass, each parasitoid species won (was in possession of the host by the end of the experiment) half of the replicates, and the number of times each wasp species contacted host in the first place was similar, without affecting replicate outcome (who ultimately won). Both species started agonistic and non-agonistic encounters. This study provides information about the potential interspecific competition between these parasitoids, which contributes to evaluate the compatibility of multiple natural enemies' biological control programs for stink bugs.


Assuntos
Hemípteros/parasitologia , Controle Biológico de Vetores/métodos , Animais , Comportamento Animal/fisiologia , Feminino , Hemípteros/fisiologia , Interações Hospedeiro-Parasita , Masculino , Oviposição , Óvulo/fisiologia , Soja , Vespas/parasitologia
11.
J Plant Physiol ; 243: 153047, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31639538

RESUMO

Acyl-CoA oxidase (ACX; EC 1.3.3.6) plays a vital role in the biosynthesis of jasmonic acid (JA) in plant peroxisomes. We previously identified an herbivore-induced gene CsACX1 in tea plant (Camellia sinensis) and showed CsACX1 was involved in the wound-induced synthesis of jasmonic acid (JA). Here, another ACX gene CsACX3 was isolated from tea plant. CsACX3 was predicted to consist of 684 amino acid residues. CsACX3 can be induced by mechanical wounding, JA application, and infestation by the tea geometrid Ectropis obliqua Prout and the tea green leafhopper Empoasca (Matsumurasca) onukii Matsuda. These expression patterns are consistent with the previously reported expression pattern of CsACX1 under such treatments. Recombinant CsACX3 showed preference for medium-chain acyl-coA oxidase substrates (C8- to C14-CoA). CsACX3 expression could also be induced by the infection of a pathogen Colletotrichum gloeosporioides (Cgl), and the increased ACX activities in tea plants were correlated with the Cgl-induced CsACX3 expression. Cgl could not induce the expression of CsACX1, which showed preference for C12- to C16-CoA substrates. The constitutive expression of CsACX3 rescued wound-induced JA biosynthesis and enhanced the Cgl-induced JA biosynthesis in Arabidopsis mutant atacx1. However, constitutive expression of CsACX1 could not enhance the Cgl-induced JA biosynthesis in atacx1 plant. These results indicate that CsACX1 and CsACX3 functions overlap and have distinct roles in the wound- and pathogen-activated de novo JA synthesis via enzymatic routes that utilize different ACX isozymes in tea plant.


Assuntos
Acil-CoA Oxidase/genética , Camellia sinensis/genética , Ciclopentanos/metabolismo , Expressão Gênica , Oxilipinas/metabolismo , Proteínas de Plantas/genética , Acil-CoA Oxidase/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Camellia sinensis/enzimologia , Camellia sinensis/metabolismo , Colletotrichum/fisiologia , Comportamento Alimentar , Cadeia Alimentar , Hemípteros/fisiologia , Isoenzimas/genética , Isoenzimas/metabolismo , Mariposas/fisiologia , Filogenia , Doenças das Plantas/microbiologia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
12.
Elife ; 82019 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-31478483

RESUMO

Insects are the only known animals in which sexual differentiation is controlled by sex-specific splicing. The doublesex transcription factor produces distinct male and female isoforms, which are both essential for sex-specific development. dsx splicing depends on transformer, which is also alternatively spliced such that functional Tra is only present in females. This pathway has evolved from an ancestral mechanism where dsx was independent of tra and expressed and required only in males. To reconstruct this transition, we examined three basal, hemimetabolous insect orders: Hemiptera, Phthiraptera, and Blattodea. We show that tra and dsx have distinct functions in these insects, reflecting different stages in the changeover from a transcription-based to a splicing-based mode of sexual differentiation. We propose that the canonical insect tra-dsx pathway evolved via merger between expanding dsx function (from males to both sexes) and narrowing tra function (from a general splicing factor to dedicated regulator of dsx).


Assuntos
Processamento Alternativo , Baratas/fisiologia , Hemípteros/fisiologia , Proteínas de Insetos/biossíntese , Ftirápteros/fisiologia , Desenvolvimento Sexual , Fatores de Transcrição/biossíntese , Animais , Baratas/genética , Hemípteros/genética , Proteínas de Insetos/genética , Ftirápteros/genética , Isoformas de Proteínas/biossíntese , Isoformas de Proteínas/genética , Fatores de Transcrição/genética
13.
Insect Biochem Mol Biol ; 113: 103211, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31425852

RESUMO

Wolbachia are intracellular bacteria that manipulate host reproduction by several mechanisms including cytoplasmic incompatibility (CI). However, the underlying mechanisms of Wolbachia-induced CI are not entirely clear. Here, we monitored the Wolbachia distribution in the male gonads of the small brown planthopper (Laodelphax striatellus, SBPH) at different development stages, and investigated the influence of Wolbachia on male gonads by a quantitative proteomic analysis. A total of 276 differentially expressed proteins were identified, with the majority of them participating in metabolism, modification, and reproduction. Knocking down the expression of outer dense fiber protein (ODFP) and venom allergen 5-like (VA5L) showed decreased egg reproduction, and these two genes might be responsible for Wolbachia improved fecundity in infected L. striatellus; whereas knocking down the expression of cytosol amino-peptidase-like (CAL) significantly decreased the egg hatch rate in Wolbachia-uninfected L. striatellus, but not in the Wolbachia-infected one. Considering that the mRNA/protein level of CAL was downregulated by Wolbachia infection and dsCAL treatment closely mimicked Wolbachia-induced CI, we presumed that CAL might be one of the factors determining the CI phenotype.


Assuntos
Hemípteros/fisiologia , Proteínas de Insetos/genética , Wolbachia/fisiologia , Animais , Gônadas/crescimento & desenvolvimento , Gônadas/microbiologia , Hemípteros/genética , Hemípteros/crescimento & desenvolvimento , Proteínas de Insetos/metabolismo , Masculino , Ninfa/genética , Ninfa/crescimento & desenvolvimento , Proteoma , Proteômica , Reprodução
14.
Virol J ; 16(1): 106, 2019 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-31438971

RESUMO

BACKGROUND: Plant viruses can affect vector's behaviors in order to enhance viral transmission. Cucurbit chlorotic yellows virus (CCYV) (genus Crinivirus) is an emergent RNA plant virus and is transmitted specifically by biotypes B and Q of tobacco whitefly, Bemisia tabaci (Gennadius), in a semipersistent manner. METHODS: We used the electrical penetration graph (EPG) to investigate the effect of CCYV on the feeding behaviors of B. tabaci biotypes B and Q. RESULTS: CCYV could affect, both directly and indirectly, the feeding behaviors of B. tabaci to various degrees, depending on biotypes and sexes of the insect. CCYV showed stronger direct effects on biotype Q than on biotype B in terms of increased non-phloem probing and phloem salivation. CCYV increased non-phloem probing and phloem salivation more on females than on males of biotype Q, and increased phloem salivation more on females than on males of biotype B. CCYV had stronger indirect effects, via virus-infested plants, on biotype B than on biotype Q by enhancing phloem sap ingestion and feeding bouts. CCYV increased non-phloem probing and feeding bouts more on males than on females of biotype B, and decreased phloem sap ingestion more on males than on females on biotype Q indirectly. CONCLUSIONS: The results clearly indicated that CCYV affects the feeding behaviors of B. tabaci, which may lead to increased ability of the B. tabaci for CCYV transmission.


Assuntos
Crinivirus , Comportamento Alimentar , Hemípteros/fisiologia , Hemípteros/virologia , Doenças das Plantas/virologia , Animais , Feminino , Insetos Vetores/fisiologia , Insetos Vetores/virologia , Masculino , Floema , Fatores Sexuais
15.
GM Crops Food ; 10(3): 170-180, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31366274

RESUMO

Interspecific interactions are complex in agro-ecosystems and could be affected by agricultural technologies including transgenic crop planting. Few studies focused on the effects of Bt crops on the interspecific interactions of non-target organisms. Here we assessed the effects of transgenic cry2A rice (Cry2A rice) on the interspecific interaction between two rice planthoppers, namely, Nilaparvata lugens (the brown planthopper, BPH) and Sogatella furcifera (the white-backed planthopper, WBPH). Cry2A rice showed no significant effects on most biological parameters of these two rice planthoppers, except for wet weight of BPH female adults and development duration of WBPH female nymphs. In contrast, interspecific interactions between BPH and WBPH showed significant impacts on their biological parameters, no matter on Cry2A rice or non-transgenic control. In two-factor analysis combing rice line and interspecific interaction together, the interaction between these two factors did not affect most biological parameters of neither planthopper species, except for development duration of BPH female nymphs and WBPH nymphs (both male and female). Additionally, the egg distributions of BPH and WBPH had no significant differences between Cry2A and non-Cry2A treatments. Results of field experiments showed that Cry2A rice did not affect their population densities at most sampling dates in a five-year survey, and the interaction between BPH and WBPH showed no significant differences in both Cry2A and non-Cry2A rice paddies. In conclusion, our tested Cry2A rice would not affect the interspecific interactions between BPH and WBPH based both laboratory and field results.


Assuntos
Proteínas de Bactérias/metabolismo , Endotoxinas/metabolismo , Hemípteros/fisiologia , Proteínas Hemolisinas/metabolismo , Oryza/parasitologia , Animais , Proteínas de Bactérias/genética , Endotoxinas/genética , Feminino , Proteínas Hemolisinas/genética , Interações Hospedeiro-Parasita , Masculino , Oryza/genética , Plantas Geneticamente Modificadas/parasitologia , Especificidade da Espécie
16.
Enzyme Microb Technol ; 129: 109358, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31307582

RESUMO

Many bacterial and viral plant pathogens are transmitted by insect vectors, and pathogen-mediated alterations of plant physiology often influence insect vector behavior and fitness. It remains largely unknown for most plant pathogens whether, and how, they might directly alter the physiology of their insect vectors in ways that promote pathogen transmission. Here we examined whether the presence of "Candidatus Liberibacter solanacearum" ("Ca. L. solanacearum"), an obligate bacterial pathogen of plants and of its psyllid vector alters the physiochemical environment within its insect vector, the potato psyllid (Bactericera cockerelli). Microelectrodes were used to measure the local pH and oxygen tension within the abdomen of "Ca. L. solanacearum"-free psyllids and those infected with "Ca. L. solanacearum". The hemolymph of infected psyllids had higher pH at 9.09 ± 0.12, compared to "Ca. L. solanacearum"-free psyllids (8.32 ± 0.11) and a lower oxygen tension of 33.99% vs. 67.83%, respectively. The physicochemical conditions inside "Ca. L. solanacearum"-free and -infected psyllids body differed significantly with the infected psyllids having a higher hemolymph pH and lower oxygen tension than "Ca. L. solanacearum"-free psyllids. Notably, the bacterial titer increased under conditions of higher pH and lower oxygen tension values. This suggests that the vector's physiology is altered by the presence of the pathogen, potentially, resulting in a more conducive environment for "Ca. L. solanacearum" survival and subsequent transmission.


Assuntos
Hemípteros/microbiologia , Insetos Vetores/microbiologia , Rhizobiaceae/fisiologia , Animais , Hemípteros/fisiologia , Concentração de Íons de Hidrogênio , Insetos Vetores/fisiologia , Doenças das Plantas/microbiologia
17.
Arch Virol ; 164(9): 2333-2338, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31187278

RESUMO

Grapevine leafroll-associated virus 3 (GLRaV-3) is an economically significant virus of grapevines, with secondary spread mediated by several species of mealybug and soft scale insects. To better understand virus-vector interactions, sensitive virus detection in these insects is a key tool. In this research, two new hydrolysis-probe-based real-time assays for GLRaV-3 detection were developed and compared to three existing assays. Of the five assays compared, the one-step RT-qPCR probe-based assay was the most sensitive and reliable, with as few as 10 virus RNA copies detected. This is the first description of a real-time molecular assay for virus detection in mealybugs with such sensitivity.


Assuntos
Closteroviridae/isolamento & purificação , Hemípteros/virologia , Insetos Vetores/virologia , Doenças das Plantas/virologia , Vitis/virologia , Animais , Closteroviridae/classificação , Closteroviridae/genética , Closteroviridae/fisiologia , Hemípteros/fisiologia , Insetos Vetores/fisiologia
18.
Int J Mol Sci ; 20(12)2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31226870

RESUMO

Plants undergo several but very precise molecular, physiological, and biochemical modulations in response to biotic stresses. Mitogen-activated protein kinase (MAPK) cascades orchestrate multiple cellular processes including plant growth and development as well as plant responses against abiotic and biotic stresses. However, the role of MAPK kinases (MAPKKs/MKKs/MEKs) in the regulation of plant resistance to herbivores has not been extensively investigated. Here, we cloned a rice MKK gene, OsMKK3, and investigated its function. It was observed that mechanical wounding, infestation of brown planthopper (BPH) Nilaparvata lugens, and treatment with methyl jasmonate (MeJA) or salicylic acid (SA) could induce the expression of OsMKK3. The over-expression of OsMKK3 (oe-MKK3) increased levels of jasmonic acid (JA), jasmonoyl-L-isoleucine (JA-Ile), and abscisic acid (ABA), and decreased SA levels in rice after BPH attack. Additionally, the preference for feeding and oviposition, the hatching rate of BPH eggs, and BPH nymph survival rate were significantly compromised due to over-expression of OsMKK3. Besides, oe-MKK3 also augmented chlorophyll content but impaired plant growth. We confirm that MKK3 plays a pivotal role in the signaling pathway. It is proposed that OsMKK3 mediated positive regulation of rice resistance to BPH by means of herbivory-induced phytohormone dynamics.


Assuntos
Hemípteros/fisiologia , Herbivoria , MAP Quinase Quinase 3/metabolismo , Oryza/fisiologia , Proteínas de Plantas/metabolismo , Ácido Abscísico/metabolismo , Animais , Ciclopentanos/metabolismo , Isoleucina/análogos & derivados , Isoleucina/metabolismo , Oxilipinas/metabolismo , Reguladores de Crescimento de Planta/metabolismo
19.
BMC Plant Biol ; 19(1): 270, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31226939

RESUMO

BACKGROUND: The Bemisia tabaci is a major leaf feeding insect pest to pepper (Capsicum annuum), causing serious damage to pepper growth and yield. It is particularly important to study the mechanism of pepper resistance to B. tabaci, and to breed and promote the varieties of pepper resistant to B. tabaci. However, very limited molecular mechanism is available about how plants perceive and defend themselves from the destructive pest. Proteome technologies have provided an idea method for studying plant physiological processes in response to B. tabaci. RESULTS: Here, a highly resistant genotype and a highly susceptible genotype were exposed to B. tabaci feeding for 48 h to explore the defense mechanisms of pepper resistance to B. tabaci. The proteomic differences between both genotypes were compared using isobaric tag for relative and absolute quantification (iTRAQ). The quantitative data were validated by parallel reaction monitoring (PRM). The results showed that 37 differential abundance proteins (DAPs) were identified in the RG (resistant genotype), while 17 DAPs were identified in the SG (susceptible genotype) at 48 h after B. tabaci feeding. 77 DAPs were identified when comparing RG with SG without feeding. The DAP functions were determined for the classification of the pathways, mainly involved in redox regulation, stress response, protein metabolism, lipid metabolism and carbon metabolism. Some candidate DAPs are closely related to B. tabaci resistance such as annexin D4-like (ANN4), calreticulin-3 (CRT3), heme-binding protein 2-like (HBP1), acidic endochitinase pcht28-like (PR3) and lipoxygenase 2 (LOX2). CONCLUSIONS: Taken together, this study indicates complex resistance-related events in B. tabaci interaction, provides novel insights into the molecular mechanism underlying the response of plant to B. tabaci, and identifies some candidate proteins against B. tabaci attack.


Assuntos
Capsicum/parasitologia , Resistência à Doença/genética , Hemípteros/fisiologia , Proteínas de Plantas/fisiologia , Animais , Capsicum/imunologia , Genótipo , Espectrometria de Massas/métodos , Proteínas de Plantas/genética , Proteoma , Proteômica/métodos
20.
J Insect Sci ; 19(3)2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31234208

RESUMO

The tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a destructive pest of tomato that can cause up to 100% yield loss. The predatory bug Nabis pseudoferus (Remane) (Hemiptera: Nabidae) and the parasitoid Trichogramma brassicae (Bezdenko) (Hymenoptera: Trichogrammatidae) are natural enemies of this pest. Since the interaction between predators and parasitoids in different trophic levels including intraguild predation (IGP) can decrease or increase the efficiency of natural enemies, the effects of age-dependent parasitism of host eggs on IGP between these two species were investigated under laboratory conditions. In no-choice and choice preference tests, the predatory bug was exposed to 40 parasitized and nonparasitized eggs of different ages (24, 48, and 72 h old). Investigation of switching behavior was conducted using various combinations of tomato leafminer eggs (30:90, 45:75, 60:60, 75:45, and 90:30 nonparasitized:parasitized eggs) using eggs of different ages (24, 48, and 72 h old). In no-choice tests, the highest feeding rate of the predatory bug was 39.21 ± 0.36 eggs on 24-h-old nonparasitized eggs and the lowest feeding rate was 1.4 ± 0.80 eggs on 72-h-old parasitized eggs. In choice tests, comparison of the Manly's ß indices indicated that the predatory bug preferred to feed on nonparasitized eggs with 48- and 72-h-old eggs, but there was no significant preference for the 24-h-old eggs. Results of switching test showed that the linear regression between Manly's ß index and different ratios of nonparasitized eggs to parasitized and nonparasitized eggs was not significant in 72-h-old eggs. However, this regression was significant with 24- and 48-h-old eggs and the predator's preference was dependent upon the ratio of nonparasitized and parasitized tomato leafminer eggs. Results of the current study showed that the increasing age of parasitized egg decreased intensity of IGP between N. pseudoferus and T. brassicae.


Assuntos
Hemípteros/fisiologia , Mariposas/parasitologia , Óvulo/parasitologia , Comportamento Predatório , Vespas/fisiologia , Animais , Comportamento de Escolha , Feminino , Interações Hospedeiro-Parasita , Mariposas/crescimento & desenvolvimento , Óvulo/crescimento & desenvolvimento
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