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2.
J Helminthol ; 97: e11, 2023 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-36698320

RESUMO

A new isolate of Mesorhabditis monhystera (Bütschli, ) Dougherty, is described and illustrated with morphological and molecular data. The phylogenetic analysis based on the D2/D3 segment of 28S rDNA using the Bayesian inference method, revealed monophyly of the genus Mesorhabditis as the subordinate taxa clustered in one clade. The clade further divided into two subclades representing the Monhystera-group and Spiculigera-group with 100% posterior probability values. However, GenBank sequences of several species constituting the Monhystera-group, showed high similarity and very little genetic divergence (98-99%) of up to 4-5 bases. In order to ascertain the status of those isolates, detailed morphological comparison is provided along with a pictorial key. A sequence-based phylogeography of haplogroups of Mesorhabditis using the median-joining network method, was also inferred. The results suggested the need for morphological validation of a species before its sequences are deposited in GenBank.


Assuntos
Rabditídios , Rhabditoidea , Animais , Filogenia , Teorema de Bayes , Elétrons , Microscopia Eletrônica de Varredura
3.
PLoS One ; 18(1): e0280675, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36689436

RESUMO

Soil-borne nematodes establish close associations with several bacterial species. Whether they confer benefits to their hosts has been investigated in only a few nematode-bacteria systems. Their ecological function, therefore, remains poorly understood. In this study, we isolated several bacterial species from rhabditid nematodes, molecularly identified them, evaluated their entomopathogenic potential on Galleria mellonella larvae, and measured immune responses of G. mellonella larvae to their infection. Bacteria were isolated from Acrobeloides sp., A. bodenheimeri, Heterorhabditis bacteriophora, Oscheius tipulae, and Pristionchus maupasi nematodes. They were identified as Acinetobacter sp., Alcaligenes sp., Bacillus cereus, Enterobacter sp., Kaistia sp., Lysinibacillus fusiformis, Morganella morganii subsp. morganii, Klebsiella quasipneumoniae subsp. quasipneumoniae, and Pseudomonas aeruginosa. All bacterial strains were found to be highly entomopathogenic as they killed at least 53.33% G. mellonella larvae within 72h post-infection, at a dose of 106 CFU/larvae. Among them, Lysinibacillus fusiformis, Enterobacter sp., Acinetobacter sp., and K. quasipneumoniae subsp. quasipneumoniae were the most entomopathogenic bacteria. Insects strongly responded to bacterial infection. However, their responses were apparently little effective to counteract bacterial infection. Our study, therefore, shows that bacteria associated with soil-borne nematodes have entomopathogenic capacities. From an applied perspective, our study motivates more research to determine the potential of these bacterial strains as biocontrol agents in environmentally friendly and sustainable agriculture.


Assuntos
Infecções Bacterianas , Rabditídios , Rhizobiaceae , Animais , Solo , Insetos , Larva/microbiologia , Rabditídios/fisiologia , Fusobacterium nucleatum
4.
Folia Parasitol (Praha) ; 702023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36645055

RESUMO

Two species of Spinitectus Fourment, 1884 have been recorded from southern Africa, namely Spinitectus polli Campana-Rouget, 1961 and Spinitectus petterae Boomker, 1993, both from the Limpopo River system. Spinitectus petterae was described from North African catfish, Clarias gariepinus (Burchell), whereas S. polli infects squeakers, Synodontis spp. During parasitological surveys in the Vaal River system (Orange River catchment), Spinitectus specimens were collected from C. gariepinus. These systems are adjacent but not connected. Therefore, this study aimed to identify the specimens collected using morphological and molecular techniques. The morphological study included light and scanning electron microscopy of whole specimens and excised spicules. Specimens were genetically characterised using 18S rDNA, 28S rDNA and cox1 mtDNA. Additionally, immature specimens of S. petterae were collected near the type locality. Morphological characteristics were most similar to S. petterae from C. gariepinus, whereas genetic data were dissimilar to all available data for the genus. Additional morphological characteristics noted for S. petterae in the present study were the details of the left and right spicule structure and the porous structures on the pseudolabia. Specimens from the Vaal River system differed from those originally described as S. petterae by additional spines posterior to the third ring, lacking caudal alae and variable total body and male oesophagus length. Based on 18S rDNA, haplotypes from the type locality varied only slightly from the study material, supporting the morphological identification. However, 28S rDNA and, more conspicuously, cox1 mtDNA displayed substantial variation between specimens from these localities, which needs further investigation. Haplotypes generated in the present study were highly dissimilar to those characterised for S. petterae from Tanzania and Egypt. Nevertheless, the nematodes collected from C. gariepinus in the Vaal River system are considered S. petterae. This study expands the geographical distribution and adds additional morphological and genetic information for S. petterae, contributing to the limited knowledge of African species of Spinitectus.


Assuntos
Peixes-Gato , Rabditídios , Spiruroidea , Animais , Masculino , Rios , Microscopia Eletrônica de Varredura , DNA Ribossômico
5.
J Invertebr Pathol ; 196: 107870, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36493843

RESUMO

Larvae of the invasive pest Drosophila suzukii are susceptible to the Steinernema carpocapsae - Xenorhabdus nematophila complex and an assessment of the immune-regulatory system activation in this insect was performed to understand the response to the nematode infection. The expressions of 14 immune-related genes of different pathways (Imd, Toll, Jak-STAT, ProPO, JNK, TGF-ß) were analyzed using qRT-PCR to determine variations after nematode penetration (90 min and 4 h) and after bacterial release (14 h). Before the bacteria were present, the nematodes were not recognized by the immune system of the larvae and practically none of the analyzed pathways presented variations when compared with the non-infected larvae. However, after the X. nematophila were released, PGRP-LC was activated leading to the gene upregulation of antimicrobial peptides of both the Toll and Imd pathways. Interestingly, the cellular response was inactive during the infection course as Jak/STAT and pro-phenoloxidase genes remained unresponsive to the presence of both pathogens. These results illustrate how D. suzukii immune pathways responded differently to the nematode and bacteria along the infection course.


Assuntos
Rabditídios , Xenorhabdus , Animais , Drosophila , Larva/microbiologia , Xenorhabdus/genética , Simbiose , Rabditídios/genética
6.
PLoS One ; 17(12): e0278049, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36454864

RESUMO

BACKGROUND: Biopurification has been used to disclose an evolutionarily conserved inhibitory reproductive hormone involved in tissue mass determination. A (rat) bioassay-guided physicochemical fractionation using ovine materials yielded via Edman degradation a 14-residue amino acid (aa) sequence. As a 14mer synthetic peptide (EPL001) this displayed antiproliferative and reproduction-modulating activity, while representing only a part of the native polypeptide. Even more unexpectedly, a scrambled-sequence control peptide (EPL030) did likewise. METHODS: Reproduction has been investigated in the nematode Steinernema siamkayai, using a fermentation system supplemented with different concentrations of exogenous hexapeptides. Peptide structure-activity relationships have also been studied using prostate cancer and other mammalian cells in vitro, with peptides in solution or immobilized, and via the use of mammalian assays in vivo and through molecular modelling. RESULTS: Reproduction increased (x3) in the entomopathogenic nematode Steinernema siamkayai after exposure to one synthetic peptide (IEPVFT), while fecundity was reduced (x0.5) after exposure to another (KLKMNG), both effects being dose-dependent. These hexamers are opposite ends of the synthetic peptide KLKMNGKNIEPVFT (EPL030). Bioactivity is unexpected as EPL030 is a control compound, based on a scrambled sequence of the test peptide MKPLTGKVKEFNNI (EPL001). EPL030 and EPL001 are both bioinformatically obscure, having no convincing matches to aa sequences in the protein databases. EPL001 has antiproliferative effects on human prostate cancer cells and rat bone marrow cells in vitro. Intracerebroventricular infusion of EPL001 in sheep was associated with elevated growth hormone in peripheral blood and reduced prolactin. The highly dissimilar EPL001 and EPL030 nonetheless have the foregoing biological effects in common in mammalian systems, while being divergently pro- and anti-fecundity respectively in the nematode Caenorhabditis elegans. Peptides up to a 20mer have also been shown to inhibit the proliferation of human cancer and other mammalian cells in vitro, with reproductive upregulation demonstrated previously in fish and frogs, as well as nematodes. EPL001 encodes the sheep neuroendocrine prohormone secretogranin II (sSgII), as deduced on the basis of immunoprecipitation using an anti-EPL001 antibody, with bespoke bioinformatics. Six sSgII residues are key to EPL001's bioactivity: MKPLTGKVKEFNNI. A stereospecific bimodular tri-residue signature is described involving simultaneous accessibility for binding of the side chains of two specific trios of amino acids, MKP & VFN. An evolutionarily conserved receptor is conceptualised having dimeric binding sites, each with ligand-matching bimodular stereocentres. The bioactivity of the 14mer control peptide EPL030 and its hexapeptide progeny is due to the fortuitous assembly of subsets of the novel hormonal motif, MKPVFN, a default reproductive and tissue-building OFF signal.


Assuntos
Neoplasias da Próstata , Rabditídios , Humanos , Masculino , Animais , Ovinos , Ratos , Reprodução , Mamíferos , Caenorhabditis elegans , Hormônios
7.
Int J Mol Sci ; 23(23)2022 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-36499649

RESUMO

Bursaphelenchus xylophilus is considered the most dangerous quarantine pest in China. It causes enormous economic and ecological losses in many countries from Asia and Europe. The glycoside hydrolase 45 gene family has been demonstrated in early studies to contribute to the cell wall degradation ability of B. xylophilus during its infection. However, the copy number variation (CNV) of the GH45 gene and its association with B. xylophilus pathogenicity were not fully elucidated. In this study, we found that the GH45 gene with two copies is the most predominant type among 259 B. xylophilus strains collected from China and Japan. Additionally, 18 strains are identified as GH45 genes with a single copy, and only two strains are verified to have three copies. Subsequent expression analysis and inoculation test suggest that the copy numbers of the GH45 gene are correlated with gene expression as well as the B. xylophilus pathogenicity. B. xylophilus strains with more copies of the GH45 gene usually exhibit more abundant expression and cause more severe wilt symptoms on pine trees. The aforementioned results indicated the potential regulatory effects of CNV in B. xylophilus and provided novel information to better understand the molecular pathogenesis of this devastating pest.


Assuntos
Pinus , Rabditídios , Tylenchida , Animais , Tylenchida/genética , Variações do Número de Cópias de DNA , Glicosídeo Hidrolases/genética , Doenças das Plantas
8.
Int J Mol Sci ; 23(23)2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36499385

RESUMO

The pinewood nematode, Bursaphelenchus xylophilus, has been determined as one of the world's top ten plant-parasitic nematodes. It causes pine wilt, a progressive disease that affects the economy and ecologically sustainable development in East Asia. B. xylophilus secretes pathogenic proteins into host plant tissues to promote infection. However, little is known about the interaction between B. xylophilus and pines. Previous studies reported transthyretin proteins in some species and their strong correlation with immune evasion, which has also been poorly studied in B. xylophilus. In this study, we cloned and functionally validated the B. xylophilus pathogenic protein BxTTR-52, containing a transthyretin domain. An in situ hybridization assay demonstrated that BxTTR-52 was expressed mainly in the esophageal glands of B. xylophilus. Confocal microscopy revealed that BxTTR-52-RFP localized to the nucleus, cytoplasm, and plasma membrane. BxTTR-52 recombinant proteins produced by Escherichia coli could be suppressed by hydrogen peroxide and antioxidant enzymes in pines. Moreover, silencing BxTTR-52 significantly attenuated the morbidity of Pinus thunbergii infected with B. xylophilus. It also suppressed the expression of pathogenesis-related genes in P. thunbergii. These results suggest that BxTTR-52 suppresses the plant immune response in the host pines and might contribute to the pathogenicity of B. xylophilus in the early infection stages.


Assuntos
Pinus , Rabditídios , Tylenchida , Animais , Tylenchida/genética , Pinus/parasitologia , Virulência , Imunidade Inata , Doenças das Plantas/parasitologia
9.
J Helminthol ; 96: e84, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36377341

RESUMO

The success of the mollusc-parasitic nematode, Phasmarhabditis hermaphrodita (Schneider) Andrássy (Rhabditida: Rhabditidae), as a biological control agent in Europe has led to worldwide interest in phasmarhabditids as biocontrol agents. In this study, the mass culture potential of three phasmarhabditids, namely Phasmarhabditis papillosa, Phasmarhabditis kenyaensis and Phasmarhabditis bohemica, was assessed. In addition, ten bacterial candidates, consisting of seven associated with slugs and three associated with entomopathogenic nematodes, were investigated. The bacteria were tested for their ability to cause mortality to Deroceras invadens, as well as to support nematode growth. Initial mortality studies demonstrated that Kluyvera, Aeromonas and Pseudomonas spp. (AP3) caused 100% mortality when they were injected into the haemocoel of D. invadens. However, in growth studies, Pseudomonas sp. (AP4) was found to be the most successful bacterium, leading to recovery and reproduction in almost all nematode species, except for P. kenyaensis. In flask studies, P. bohemica, which showed exceptional growth with Pseudomonas sp. (AP1), was chosen for further investigation. The effect of inoculating flasks with different concentrations of Pseudomonas sp. (AP1), as well as with different concentrations of P. bohemica, was evaluated by assessing the nematode populations for 14 days. The results indicated that the lowest, 1% (v/v), bacteria inoculation led to higher total nematode and to infective juvenile (IJ) yield, with flasks with the highest IJ inoculum (3000 IJs/ml) having a positive effect on the total number of nematodes and IJs in cultures of P. bohemica. This study presents improvements for the mass-culturing of nematodes associated with molluscs.


Assuntos
Gastrópodes , Rabditídios , Rhabditoidea , Animais , Moluscos/parasitologia , Gastrópodes/parasitologia , Agentes de Controle Biológico , Controle Biológico de Vetores/métodos
10.
Genes (Basel) ; 13(11)2022 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-36360193

RESUMO

Bursaphelenchus xylophilus (PWN) causes pine wilt disease (PWD), which is one of the most devastating pine diseases worldwide. Cytochrome P450 (CYP) catalyzes the biosynthetic metabolism of terpenoids and plays an important role in the modification of secondary metabolites in all living organisms. We investigated the molecular characteristics and biological functions of Bx-cyp29A3 in B. xylophilus. The bioinformatics analysis results indicated that Bx-cyp29A3 has a transmembrane domain and could dock with L(-)-carvone. The gene expression pattern indicated that Bx-cyp29A3 was expressed in 0.2, 0.4, 0.6, 0.8, and 1.0 mg/mL L(-)-carvone solutions. The Bx-cyp29A3 expression increased in a dose-dependent manner and peaked at 24 h of exposure when the L(-)-carvone solution concentration was 0.8 mg/mL. However, the gene expression peaked at 0.6 mg/mL after 36 h. Furthermore, RNA interference (RNAi) indicated that Bx-cyp29A3 played an essential role in the response to L(-)-carvone. The mortality rates of the Bx-cyp29A3 knockdown groups were higher than those of the control groups in the 0.4, 0.6, 0.8, and 1.0 mg/mL carvone solutions after 24 h of exposure or 36 h of exposure. In summary, bioinformatics provided the structural characteristics and conserved sequence properties of Bx-cyp29A3 and its encoded protein, which provided a target gene for the study of the P450 family of B. xylophilus. Gene silencing experiments clarified the function of Bx-cyp29A3 in the immune defense of B. xylophilus. This study provides a basis for the screening of new molecular targets for the prevention and management of B. xylophilus.


Assuntos
Rabditídios , Tylenchida , Animais , Tylenchida/genética , Xylophilus , Doenças das Plantas/genética , Sistema Enzimático do Citocromo P-450/genética
11.
Int J Mol Sci ; 23(21)2022 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-36361788

RESUMO

The α2δ subunit is a high-voltage activated (HVA) calcium channel (Cav1 and Cav2) auxiliary subunit that increases the density and function of HVA calcium channels in the plasma membrane of mammals. However, its function in plant parasitic nematodes remains unknown. In this study, we cloned the full-length cDNA sequence of the voltage-gated calcium channel (VGCC) α2δ subunit (named DdCavα2δ) in Ditylenchus destructor. We found that DdCavα2δ tends to be expressed in the egg stage, followed by the J3 stage. RNA-DIG in situ hybridization experiments showed that the DdCavα2δ subunit was expressed in the body wall, esophageal gland, uterus, post uterine, and spicules of D. destructor. The in vitro application of RNA interference (RNAi) affected the motility, reproduction, chemotaxis, stylet thrusting, and protein secretion of D. destructor to different degrees by targeting DdCα1D, DdCα1A, and DdCavα2δ in J3 stages, respectively. Based on the results of RNAi experiments, it was hypothesized that L-type VGCC may affect the motility, chemotaxis, and stylet thrusting of D. destructor. Non-L-type VGCC may affect the protein secretion and reproduction of D. destructor. The DdCavα2δ subunit gene also affected the motility, chemotaxis, and reproduction of D. destructor. These findings reveal the independent function of the VGCC α2δ subunit in D. destructor as well as give a theoretical foundation for future research on plant parasitic nematode VGCC.


Assuntos
Parasitos , Rabditídios , Tylenchida , Animais , Feminino , Rabditídios/genética , Canais de Cálcio Tipo L , Membrana Celular , Plantas/parasitologia , Cálcio , Mamíferos
12.
Int J Mol Sci ; 23(20)2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36293134

RESUMO

RNA interference (RNAi) efficiency dramatically varies among different nematodes, which impacts research on their gene function and pest control. Bursaphelenchus xylophilus is a pine wood nematode in which RNAi-mediated gene silencing has unstable interference efficiency through soaking in dsRNA solutions, the factors of which remain unknown. Using agarose gel electrophoresis, we found that dsRNA can be degraded by nematode secretions in the soaking system which is responsible for the low RNAi efficiency. Based on the previously published genome and secretome data of B. xylophilus, 154 nucleases were screened including 11 extracellular nucleases which are potential factors reducing RNAi efficacy. To confirm the function of nucleases in RNAi efficiency, eight extracellular nuclease genes (BxyNuc1-8) were cloned in the genome. BxyNuc4, BxyNuc6 and BxyNuc7 can be upregulated in response to dsGFP, considered as the major nuclease performing dsRNA degradation. After soaking with the dsRNA of nucleases BxyNuc4/BxyNuc6/BxyNuc7 and Pat10 gene (ineffective in RNAi) simultaneously for 24 h, the expression of Pat10 gene decreased by 23.25%, 26.05% and 11.29%, respectively. With soaking for 36 h, the expression of Pat10 gene decreased by 43.25% and 33.25% in dsBxyNuc6+dsPat10 and dsBxyNuc7+dsPat10 groups, respectively. However, without dsPat10, dsBxyNuc7 alone could cause downregulation of Pat10 gene expression, while dsBxyNuc6 could not disturb this gene. In conclusion, the nuclease BxyNuc6 might be a major barrier to the RNAi efficiency in B. xylophilus.


Assuntos
Pinus , Rabditídios , Tylenchida , Animais , Tylenchida/fisiologia , Interferência de RNA , Xylophilus , Pinus/genética , Doenças das Plantas , RNA de Cadeia Dupla/genética , RNA de Cadeia Dupla/metabolismo , Rabditídios/metabolismo , Endonucleases/genética , Endonucleases/metabolismo
13.
Int J Mol Sci ; 23(20)2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36293146

RESUMO

Fatty acid and retinol binding proteins (FAR) are unique proteins found in nematodes and are considered potential targets for controlling these parasites. However, their functions in nematode parasitism and pathogenicity and interaction with hosts are still unclear. In this study, we investigated the specific roles of rice white tip nematodes (RWTNs), Aphelenchoides besseyi, and a protein, Ab-FAR-1, to elucidate the parasitic and pathogenic processes of nematodes. The results showed that the expression level of Ab-far-1 was significantly up-regulated after A. besseyi infection of the plant. The immunofluorescence and subcellular localisation showed that Ab-FAR-1 was secreted into plant tissues mainly through the body wall of nematodes and might act in the nucleus and cytoplasm of plant cells. The pathogenicity of RWTNs was enhanced in Arabidopsis thaliana overexpressing Ab-FAR-1 and inhibited in Ab-far-1 RNAi A. thaliana. Yeast two-hybrid, Co-IP, BiFC, and nematode inoculation experiments showed that Ab-FAR-1 could interact with the A. thaliana actin-depolymerizing factor protein AtADF3, and the A. thaliana adf3 mutant was more susceptible to nematodes. An in vitro actin filament depolymerisation assay demonstrated that Ab-FAR-1 could inhibit AtADF3-mediated depolymerisation of actin filaments, and the turnover process of cellular actin filaments was also affected in A. thaliana overexpressing Ab-FAR-1. In addition, flg22-mediated host defence responses were suppressed in A. thaliana overexpressing Ab-FAR-1 and adf3 mutants. Therefore, this study confirmed that RWTNs can affect the turnover of actin filament remodelling mediated by AtADF3 through Ab-FAR-1 secretion and thus inhibit plant PAMP-triggered immunity (PTI), promoting the parasitism and pathogenicity of nematodes.


Assuntos
Arabidopsis , Rabditídios , Tylenchida , Tylenchoidea , Animais , Arabidopsis/metabolismo , Virulência , Padrões Moleculares Associados a Patógenos , Actinas/metabolismo , Proteínas de Helminto/metabolismo , Tylenchida/fisiologia , Rabditídios/metabolismo , Proteínas de Ligação ao Retinol/metabolismo , Ácidos Graxos , Citoesqueleto de Actina/metabolismo , Doenças das Plantas/parasitologia , Tylenchoidea/metabolismo
14.
J Helminthol ; 96: e66, 2022 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-36093856

RESUMO

A new species of the genus Paurodontella, Paurodontella minora n. sp., collected from Alborz Province, Iran, is described and illustrated based on morphological and molecular characters. The new species is characterized by its body length of 393 (350-438) µm and 380 (n = 1) µm in female and male, respectively, 6-7 incisures in lateral field, lip region annulated and continuous with body contour, and total stylet 6.1 (5.5-7.0) µm long. Basal pharyngeal bulb with small posterior extension projecting reaching to the intestine. Excretory pore situated at the level of basal pharyngeal bulb region, no post-uterine sac, conical tail, narrowing to a rounded tip, and rare male with slender tylenchoid spicules and adanal bursa. The new species comes close in morphology and morphometrics to four known species of the genus, namely Paurodontella asymmetrica, Paurodontella balochistanica, Paurodontella densa and Paurodontella niger. In molecular phylogenetic analyses using D2-D3 expansion segments of the large subunit rDNA gene sequence, P. minora n. sp. formed a major clade with species of the genera in the family Sphaerulariidae (Paurodontella, Paurodontoides, Veleshkinema and Sphaerularia) and a sister relation with the members in the families Neotylenchidae and Anguinidae with the same clade support values in Bayesian inference.


Assuntos
Rabditídios , Animais , Teorema de Bayes , DNA Ribossômico/genética , Feminino , Humanos , Masculino , Faringe , Filogenia , Rabditídios/genética
15.
Int J Mol Sci ; 23(18)2022 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-36142347

RESUMO

Peptidases are very important to parasites, which have central roles in parasite biology and pathogenesis. In this study, by comparative genome analysis, genome-wide peptidase diversities among plant-parasitic nematodes are estimated. We find that genes encoding cysteine peptidases in family C13 (legumain) are significantly abundant in pine wood nematodes Bursaphelenchus genomes, compared to those in other plant-parasitic nematodes. By phylogenetic analysis, a clade of B. xylophilus-specific legumain is identified. RT-qPCR detection shows that these genes are highly expressed at early stage during the nematode infection process. Utilizing transgene technology, cDNAs of three species-specific legumain were introduced into the Arabidopsis γvpe mutant. Functional complementation assay shows that these B. xylophilus legumains can fully complement the activity of Arabidopsis γVPE to mediate plant cell death triggered by the fungal toxin FB1. Secretory activities of these legumains are experimentally validated. By comparative transcriptome analysis, genes involved in plant cell death mediated by legumains are identified, which enrich in GO terms related to ubiquitin protein transferase activity in category molecular function, and response to stimuli in category biological process. Our results suggest that B. xylophilu-specific legumains have potential as effectors to be involved in nematode-plant interaction and can be related to host cell death.


Assuntos
Arabidopsis , Micotoxinas , Parasitos , Pinus , Rabditídios , Tylenchida , Animais , Arabidopsis/genética , Cisteína/genética , Cisteína Endopeptidases , Peptídeo Hidrolases/genética , Filogenia , Pinus/parasitologia , Doenças das Plantas/parasitologia , Plantas/parasitologia , Transferases/genética , Tylenchida/genética , Ubiquitinas/genética , Virulência , Xylophilus
16.
Int J Mol Sci ; 23(18)2022 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-36142710

RESUMO

Pine wilt disease (PWD) is a global quarantine disease of forests that mainly affects Pinaceae species. The disease spreads rapidly. Once infected, pine trees have an extremely high mortality rate. This paper provides a summary of the common techniques used to detect PWD, including morphological-, molecular-, chemical- and physical-based methods. By comprehending the complex relationship among pinewood nematodes, vectors and host pine trees and employing the available approaches for nematode detection, we can improve the implementation of intervention and control measures to effectively reduce the damage caused by PWD. Although conventional techniques allow a reliable diagnosis of the symptomatic phase, the volatile compound detection and remote sensing technology facilitate a rapid diagnosis during asymptomatic stages. Moreover, the remote sensing technology is capable of monitoring PWD over large areas. Therefore, multiple perspective evaluations based on these technologies are crucial for the rapid and effective detection of PWD.


Assuntos
Pinus , Rabditídios , Animais
17.
Artigo em Inglês | MEDLINE | ID: mdl-36108997

RESUMO

The effects of the entomopathogenic nematode Steinernema carpocapsae on the Colorado potato beetle (CPB) Leptinotarsa decemlineata and the involvement of adipokinetic hormone (AKH) in the responsive reactions were examined in this study. It was observed that nematode application doubled the amount of AKH (Peram-CAH-I and Peram-CAH-II) in the central nervous system of L. decemlineata, indicating mobilization of anti-stress reactions in the body. Furthermore, the external co-application of Peram-CAH-II with the nematode significantly increased beetle mortality (5.6 and 1.8 times, 1 and 2 days after application, respectively). The mechanism underlying this phenomenon was investigated. As the effect on gut characteristics was equivocal, it was assumed that the nematodes profited from the observed mobilization of metabolites from the fat body into the Peram-CAH-II-induced hemolymph. This phenomenon supplied nematodes with a more nutrient-dense substrate on which they propagated. Furthermore, Peram-CAH-II lowered vitellogenin expression in the fat body, particularly in males, thus limiting the anti-pathogen defense capacity of the protein. However, there could be other possible mechanisms underpinning this chain of events. The findings could be theoretically intriguing but could also aid in developing real insect pest control methods in the future.


Assuntos
Besouros , Rabditídios , Solanum tuberosum , Animais , Hormônios de Inseto , Masculino , Oligopeptídeos , Ácido Pirrolidonocarboxílico/análogos & derivados , Rabditídios/fisiologia , Vitelogeninas
18.
Zootaxa ; 5125(5): 451-482, 2022 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-36101201

RESUMO

In a study, 13 known species of Ditylenchus Filipjev, 1936 were collected during 20132017 mainly in the southern provinces of Iran, and the variability of their morphological and morphometric characteristics was investigated. The results showed that the number of lateral lines, V and V indices, stylet and spicule length, whose coefficient of variation was less than 10%, were more stable than the other characters. The effects of different temperatures and food sources, including several plants, fungi and carrot disc on the taxonomic characters of three populations of Ditylenchus destructor, two populations of D. dipsaci, and one population of D. myceliophagus were studied. The results showed that indices V, V and MB were more stable than the others. The indices were more affected by food source than by temperature. In addition, the calculation of the correlation between some morphometric indices showed that the distances between the anterior end and vulva, and the anterior end and anus were significantly correlated with body length in all species and populations studied.


Assuntos
Rabditídios , Tylenchida , Animais , Dieta , Feminino , Plantas , Temperatura
19.
Exp Parasitol ; 242: 108380, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36116520

RESUMO

The fall webworm (FWW), Hyphantria cunea Drury (Lepidoptera: Erebidae), is an invasive and polyphagous insect pest of many economically important crops such as hazelnuts, apple, and mulberry. Recently, there have been an increasing number of reports about the damaging activities of FWW from hazelnut growing areas of Turkey indicating that currently existing control methods fail to satisfy the expectations of growers. Entomopathogenic nematodes (EPNs) in the Steinernematidae and Heterorhabditidae (Nematoda: Rhabditida) families and the symbiotic bacteria they carry in their intestine have a great potential for the management of many agriculturally important pests. In this study, the symbiotic bacteria of local EPN species (Heterorhabditis bacteriophora AVB-15, Steinernema feltiae KCS-4S, and Steinernema bicornotum MGZ-4S) recovered from the central Anatolia region was characterized using recA gene region as Photorhabdus luminescens, Xenorhabdus bovienii and Xenorhabdus budapestensis. The contact (25, 50, 100, 200 IJs/Petri) and oral efficacies of the infective juveniles (IJs) (25, 50, 100, 200 IJs/leaf) of these EPN isolates determined on 3rd/4th instar larvae, and cell-free supernatants from the identified symbiotic bacteria were evaluated separately on the 3rd and 4th larval instars of FWW in Petri dish environment under laboratory conditions (25 ± 1 °C, 60% of RH). In the Petri dish bioassays of EPN species, the most pathogenic isolate at the 1st DAT and 4th DAT was S. feltiae which caused 50% mortality at the highest concentration (200 IJs/Petri) and the highest mortality rate (97.5%) were achieved at 4th DAT by H. bacteriophora AVB-15 isolate. Surprisingly, the mortality rates were generally higher at the lowest concentrations and 82.5% mortality were reached 4th DAT by S. bicornotum at the lowest concentration (25 IJs/leaf) in the leaf bioassays. Mortality rates were higher in both Petri dish and filter paper efficacies of cell-free supernatants at the 2nd DAT and the highest mortality (87.5%) was reached in the contact efficacy studies when applied X. bovienii KCS-4S strain. The results suggest that the tested EPN species and CFSs have good potential for biological control of the larvae of FWW and can contribute to the IPM programs of FWW. However, the efficacy of both IJs of EPNs and CFSs of their symbiotic bacteria on larvae of FWW requires further studies to verify their efficiency in the field.


Assuntos
Inseticidas , Mariposas , Photorhabdus , Rabditídios , Humanos , Animais , Larva/microbiologia , Controle Biológico de Vetores
20.
Pest Manag Sci ; 78(12): 5437-5443, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36057860

RESUMO

BACKGROUND: The bioinsecticidal action of entomopathogenic nematodes (EPNs) typically relies on their symbiosis with core bacteria. However, recent studies highlighted the possible involvement of other noncore species. We have recently isolated a novel Pseudomonas protegens strain as a major agent of septicaemia in larvae of the wax moth, Galleria mellonella, infected with a soil-dwelling Steinernema feltiae strain. The actual role of this bacterium in entomopathogenesis was investigated. RESULTS: The association of P. protegens with nematodes appeared to be robust, as supported by its direct and repeated isolation from both nematodes and insect larvae infected for several consecutive generations. The bacterium appeared to be well-adapted to the insect haemocoel, being able to proliferate rapidly after the injection of even a small amount of living cells [100 colony forming units (CFU)] to a larva, causing its fast death. The bacterium also was able to act by ingestion against G. mellonella larvae [median lethal concentration (LC50 ) = 4.0 × 107 CFU mL-1 ], albeit with a slower action, which supports the involvement of specific virulence factors (e.g. chitinases, Fit toxin) to overcome the intestinal barrier to the haemocoel. Varying levels of bacterial virulence were observed on diverse target Diptera and Lepidoptera. CONCLUSION: The soil-dwelling bacterium P. protegens appears to have evolved its own potential as a stand-alone entomopathogen, yet the establishment of an opportunistic association with entomoparasitic nematodes would represent a special competitive advantage. This finding contributes to a deeper understanding of the nematode-bacteria biocontrol agent complex and the deriving paradigm of their use as biological control agents. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Mariposas , Rabditídios , Animais , Controle Biológico de Vetores , Mariposas/parasitologia , Insetos , Larva/parasitologia , Solo/parasitologia , Bactérias
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