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Li J, Dai H, Bashir A, Wang Z, An Y, Yu X, Xu L, Li L. Nematicidal activity and action mode of a methyl-accepting chemotaxis protein from Pseudomonas syringae against Caenorhabditis elegans. Heliyon 2024; 10:e30366. [PMID: 38707475 PMCID: PMC11068812 DOI: 10.1016/j.heliyon.2024.e30366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 05/07/2024] Open
Abstract
The conventional phytopathogen Pseudomonas syringae reportedly possesses several virulence determinants against Caenorhabditis elegans; however, their action mechanisms remain elusive. This study reports the nematicidal activity and action receptor of a methyl-accepting chemotaxis protein (MCP03) of a wild-type P. syringae MB03 against C. elegans. Purified MCP03 exhibited nematicidal toxicity against C. elegans at a half-lethal concentration of 124.4 μg mL-1, alongside detrimental effects on the growth and brood size of C. elegans. Additionally, MCP03-treated worms exhibited severe pathological destruction of the intestine and depressed wrinkles of the cuticle. Yeast two-hybrid assays identified a subunit of COP9 signalosome, namely CSN-5, which functioned as an MCP03 action receptor. In vitro pull-down verified the binding interaction between MCP03 and CSN-5. RNA interference assays confirmed that MCP03 antagonizes CSN-5, thereby adversely affecting the brood size and cuticle integrity of C. elegans. Following MCP03 infection, the expression of genes related to reproduction, growth, and cuticle formation, such as kgb-1, unc-98, and col-117, was considerably downregulated, indicating pathological changes in MCP03-treated nematodes. Therefore, we proposed that MCP03 antagonizes CSN-5, causing lethality as well as detrimental effects on the fertility, growth, and morphogenesis of C. elegans, which can provide new insights into the signaling pathways and mechanisms underlying the nematicidal action of MCP03 toward C. elegans.
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Affiliation(s)
- Jiaoqing Li
- Guangdong Provincial Key Laboratory of Conservation and Precision Utilization of Characteristic Agricultural Resources in Mountainous Areas, School of Life Sciences, Jiaying University, Meizhou 514015, China
| | - Haiyan Dai
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Anum Bashir
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhiyong Wang
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yimin An
- Pomelo Engineering Technology Center, School of Life Sciences, Jiaying University, Meizhou 514015, China
| | - Xun Yu
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Liangzheng Xu
- Guangdong Provincial Key Laboratory of Conservation and Precision Utilization of Characteristic Agricultural Resources in Mountainous Areas, School of Life Sciences, Jiaying University, Meizhou 514015, China
| | - Lin Li
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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Davies KG, Mohan S, Phani V, Srivastava A. Exploring the mechanisms of host-specificity of a hyperparasitic bacterium ( Pasteuria spp.) with potential to control tropical root-knot nematodes ( Meloidogyne spp.): insights from Caenorhabditis elegans. Front Cell Infect Microbiol 2023; 13:1296293. [PMID: 38173791 PMCID: PMC10761439 DOI: 10.3389/fcimb.2023.1296293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 11/22/2023] [Indexed: 01/05/2024] Open
Abstract
Plant-parasitic nematodes are important economic pests of a range of tropical crops. Strategies for managing these pests have relied on a range of approaches, including crop rotation, the utilization of genetic resistance, cultural techniques, and since the 1950's the use of nematicides. Although nematicides have been hugely successful in controlling nematodes, their toxicity to humans, domestic animals, beneficial organisms, and the environment has raised concerns regarding their use. Alternatives are therefore being sought. The Pasteuria group of bacteria that form endospores has generated much interest among companies wanting to develop microbial biocontrol products. A major challenge in developing these bacteria as biocontrol agents is their host-specificity; one population of the bacterium can attach to and infect one population of plant-parasitic nematode but not another of the same species. Here we will review the mechanism by which infection is initiated with the adhesion of endospores to the nematode cuticle. To understand the genetics of the molecular processes between Pasteuria endospores and the nematode cuticle, the review focuses on the nature of the bacterial adhesins and how they interact with the nematode cuticle receptors by exploiting new insights gained from studies of bacterial infections of Carnorhabditis elegans. A new Velcro-like multiple adhesin model is proposed in which the cuticle surface coat, which has an important role in endospore adhesion, is a complex extracellular matrix containing glycans originating in seam cells. The genes associated with these seam cells appear to have a dual role by retaining some characteristics of stem cells.
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Affiliation(s)
- Keith G. Davies
- School of Life and Medical Sciences, University of Hertfordshire, Hatfield, United Kingdom
| | - Sharad Mohan
- Division of Nematology, Indian Agricultural Research Institute, New Delhi, India
| | - Victor Phani
- Department of Agricultural Entomology, College of Agriculture, Uttar Banga Krishi Viswavidyalaya, Dakshin Dinajpur, West Bengal, India
| | - Arohi Srivastava
- Dr. D. Y Patil Biotechnology & Bioinformatics Institute, Dr. D. Y. Patil Vidyapeeth, Pune, India
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The Difference in the Bacterial Attachment among Pratylenchus neglectus Populations and Its Effect on the Nematode Infection. Microorganisms 2022; 10:microorganisms10081524. [PMID: 36013942 PMCID: PMC9414941 DOI: 10.3390/microorganisms10081524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 07/25/2022] [Accepted: 07/25/2022] [Indexed: 11/24/2022] Open
Abstract
Different bacterial isolates attach to the cuticle of plant-parasitic nematodes, affecting their interactions with the host plant. Nematode populations differ in their genetic and cuticle structures, causing variable interactions with host plants and natural enemies. In the current study, attachment assays were carried out to compare the attachment of soil bacteria in general and the bacterial isolate of Rothia sp. in particular among geographically diverse populations of Pratylenchus neglectus. Biological and molecular assays were further conducted to examine the effect of Rothia attachment on nematode penetration into barley roots and to sequence the fatty acid- and retinol-binding gene (Pn-far-1). The results showed that nematode populations of P. neglectus differed in their bacterial attachment. Soil bacteria and Rothia sp. attached specifically to the cuticle of P. neglectus and did so differently among the nematode populations. Rothia attachment caused a reduction in the infectivity of three nematode populations in barley roots. The sequencing of the far-1 gene revealed genetic variability within and among P. neglectus populations. In conclusion, the interaction between P. neglectus and their bacterial attachers occurs in a population-specific manner, elucidating an essential aspect of using biological agents to manage plant-parasitic nematodes. Key Message: 1. Geographically diverse populations of the root lesion nematode Pratylenchus neglectus differed in the soil bacterial communities attached to their cuticles. 2. The bacterial isolate of Rothia sp. attached to the cuticle of P. neglectus and reduced its penetration into the host plant in a population-specific manner. 3. The fatty acid- and retinol-binding gene (far-1) varied within and among P. neglectus populations with their different bacterial attachment.
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Characterization of Nematicidal Activity and Nematode-Toxic Metabolites of a Soilborne Brevundimonas bullata Isolate. Pathogens 2022; 11:pathogens11060708. [PMID: 35745562 PMCID: PMC9229253 DOI: 10.3390/pathogens11060708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/14/2022] [Accepted: 06/16/2022] [Indexed: 02/04/2023] Open
Abstract
The increasing prevalence of crop-threatening root-knot nematodes (RKNs) has stimulated extensive research to discover effective nematicides. A highly focused strategy for accomplishing this is the development of biocontrol agents by a variety of soilborne microorganisms, as different bacterial metabolites have demonstrated promising nematicidal activities. In this study, we characterized the nematicidal and suppressive activity of a bacterial isolate against the agriculturally important RKN Meloidogyne incognita and the model nematode Caenorhabditis elegans, and the main M. incognita-toxic metabolite of the strain. After a preliminary screening of 22 bacterial isolates with a corrected mortality (CM) of whole-cell culture greater than 50% against C. elegans from different RKN-incident soils in China, a total of 14 isolates with CM of the supernatant of culture suspension (SCS) higher than 50% against both M. incognita and C. elegans were rescreened. An isolate with the highest CM of 86.1% and 95.0% for M. incognita and C. elegans, respectively, was further identified as the species Brevundimonas bullata via morphological examination, physiological and biochemical assays and alignment analysis of 16S rRNA gene sequences. The SCS of this strain, namely, B. bullata MB756, exhibited synchronous M. incognita killing activity along with significant detrimental effects on the growth, brood size, and locomotion of C. elegans. The effects of heat treatment, pH, inoculations, and protease K proteolysis on the CM of MB756 SCS were evaluated. A major M. incognita-toxic substance in the MB756 SCS was assayed and identified using thin-layer chromatography, column chromatography and high-performance liquid chromatography with a mass spectrometer, and it was preliminarily identified as 2-ethylhexan-1-ol, with a molecular formula of C8H18O and a molecular weight of 130.3 Da.
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Abstract
Fatty acid–and retinol-binding proteins (FARs) belong to a unique family of excreted/secreted proteins (ESPs) found exclusively in nematodes. Much of our understanding of these proteins, however, is limited to their in vitro binding characteristics toward various fatty acids and retinol and has provided little insight into their in vivo functions or mechanisms. Recent research, however, has shown that FARs elicit an immunomodulatory role in plant and animal model systems, likely by sequestering lipids involved in immune signaling. This alludes to the intricate relationship between parasitic nematode effectors and their hosts.
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Srivastava A, Mohan S, Davies KG. Exploring Bacillus thuringiensis as a model for endospore adhesion and its potential to investigate adhesins in Pasteuria penetrans. J Appl Microbiol 2022; 132:4371-4387. [PMID: 35286009 PMCID: PMC9311801 DOI: 10.1111/jam.15522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 03/04/2022] [Accepted: 03/07/2022] [Indexed: 11/30/2022]
Abstract
Aims Phytonematodes are a constraint on crop production and have been controlled using nematicides; these are highly toxic and legislation in Europe and elsewhere is prohibiting their use and alternatives are being sought. Pasteuria penetrans is a hyperparasitic bacterium that form endospores and have potential to control root‐knot nematodes (Meloidogyne spp.), but their attachment to the nematode cuticle is host‐specific. Understanding host specificity has relied upon endospore inhibition bioassays using immunological and biochemical approaches. Phylogenetic analysis of survey sequences has shown P. penetrans to be closely related to Bacillus and to have a diverse range of collagen‐like fibres which we hypothesise to be involved in the endospore adhesion. However, due to the obligately hyperparasitic nature of Pasteuria species, identifying and characterizing these collagenous‐like proteins through gain of function has proved difficult and new approaches are required. Methods and Results Using antibodies raised to synthetic peptides based on Pasteuria collagen‐like genes we show similarities between P. penetrans and the more easily cultured bacterium Bacillus thuringiensis and suggest it be used as a gain of function platform/model. Using immunological approaches similar proteins between P. penetrans and B. thuringiensis are identified and characterized, one >250 kDa and another ~72 kDa are glycosylated with N‐acetylglucosamine and both of which are digested if treated with collagenase. These treatments also affected endospore attachment and suggest these proteins are involved in adhesion of endospores to nematode cuticle. Conclusion There are conserved similarities in the collagen‐like proteins present on the surface of endospores of both P. penetrans and B. thuringiensis. Significance and Impact of Study As B. thuringiensis is relatively easy to culture and can be transformed, it could be developed as a platform for studying the role of the collagen‐like adhesins from Pasteuria in endospore adhesion.
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Affiliation(s)
- Arohi Srivastava
- School of Life and Medical Sciences, University of Hertfordshire, Hatfield, AL10 9AB, UK
| | - Sharad Mohan
- Division of Nematology, Indian Agricultural Research Institute, Pusa Campus, New Delhi110012, India
| | - Keith G Davies
- School of Life and Medical Sciences, University of Hertfordshire, Hatfield, AL10 9AB, UK
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7
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Function of lipid binding proteins of parasitic helminths: still a long road. Parasitol Res 2022; 121:1117-1129. [PMID: 35169885 DOI: 10.1007/s00436-022-07463-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 02/07/2022] [Indexed: 10/19/2022]
Abstract
Infections with parasitic helminths cause severe debilitating and sometimes lethal diseases in humans and domestic animals on a global scale. Unable to synthesize de novo their own fatty acids and sterols, helminth parasites (nematodes, trematodes, cestodes) rely on their hosts for their supply. These organisms produce and secrete a wide range of lipid binding proteins that are, in most cases, structurally different from the ones found in their hosts, placing them as possible novel therapeutic targets. In this sense, a lot of effort has been made towards the structure determination of these proteins, but their precise function is still unknown. In this review, we aim to present the current knowledge on the functions of LBPs present in parasitic helminths as well as novel members of this highly heterogeneous group of proteins.
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Yuan D, Li S, Shang Z, Wan M, Lin Y, Zhang Y, Feng Y, Xu L, Xiao L. Genus-level evolutionary relationships of FAR proteins reflect the diversity of lifestyles of free-living and parasitic nematodes. BMC Biol 2021; 19:178. [PMID: 34461887 PMCID: PMC8407040 DOI: 10.1186/s12915-021-01111-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 07/29/2021] [Indexed: 01/16/2023] Open
Abstract
Background Nematodes are a widespread and diverse group comprising free-living and parasitic species, some of which have major detrimental effects on crops, animals, and human health. Genomic comparisons of nematodes may help reveal the genetic bases for the evolution of parasitic lifestyles. Fatty acid and retinol-binding proteins (FARs) are thought to be unique to nematodes and play essential roles in their development, reproduction, infection, and possibly parasitism through promoting the uptake, transport, and distribution of lipid and retinol. However, the evolution of FAR family proteins across the phylum Nematoda remains elusive. Results We report here the evolutionary relationship of the FAR gene family across nematodes. No FAR was found in Trichocephalida species and Romanomermis culicivorax from Clade I, and FAR could be found in species from Clades III, IV, and V. FAR proteins are conserved in Clade III species and separated into three clusters. Tandem duplications and high divergence events lead to variable richness and low homology of FARs in Steinernema of Clade IVa, Strongyloides of Clade IVb, and intestinal parasitic nematodes from Clades Vc and Ve. Moreover, different richness and sequence variations of FARs in pine wood, root-knot, stem, and cyst nematodes might be determined by reproduction mode or parasitism. However, murine lungworm Angiostrongylus and bovine lungworm Dictyocaulus viviparus from Clade Vd have only 3–4 orthologs of FAR. RNA-seq data showed that far genes, especially far-1 and far-2, were highly expressed in most nematodes. Angiostrongylus cantonensis FAR-1 and FAR-3 have low sequence homology and distinct ligand-binding properties, leading to differences in the cavity volume of proteins. These data indicate that FAR proteins diverged early and experienced low selective pressure to form genus-level diversity. The far genes are present in endophyte or root-colonized bacteria of Streptomyces, Kitasatospora sp., Bacillus subtilis, and Lysobacter, suggesting that bacterial far genes might be derived from plant-parasitic nematodes by horizontal gene transfer. Conclusions Data from these comparative analyses have provided insights into genus-level diversity of FAR proteins in the phylum Nematoda. FAR diversification provides a glimpse into the complicated evolution history across free-living and parasitic nematodes. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01111-3.
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Affiliation(s)
- Dongjuan Yuan
- Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Song Li
- Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Ziyu Shang
- Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Muchun Wan
- Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Yu Lin
- Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Yanhua Zhang
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China
| | - Yaoyu Feng
- Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Lian Xu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226019, China.
| | - Lihua Xiao
- Center for Emerging and Zoonotic Diseases, College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, China. .,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China.
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Paecilomyces formosus MD12, a Biocontrol Agent to Treat Meloidogyne incognita on Brinjal in Green House. J Fungi (Basel) 2021; 7:jof7080632. [PMID: 34436171 PMCID: PMC8398934 DOI: 10.3390/jof7080632] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/09/2021] [Accepted: 07/23/2021] [Indexed: 11/17/2022] Open
Abstract
The present study was carried out to analyze the potential of fungi isolated from the rhizosphere of soybean, brinjal, tomato, and potato plants. The density of fungi varied in the pot soil and rhizosphere after Paecilomyces formosus MD12 treatment. The P. formosus MD12 population was 6.3 ± 0.13 × 104 CFU g−1 in the pot planted with brinjal, and the population increased in the rhizosphere (6.72 ± 0.41 × 104 CFU g−1). P. formosus MD12 was cultured in the production medium, and the supernatant was used for egg inhibition studies on a root-knot nematode parasite, Meloidogyne incognita. It was revealed that maximum egg inhibition (94.7 ± 6.2%) was obtained at 100% concentration of extract. The culture supernatant from P. formosus MD12 affected the development of M. incognita juvenile, and the mortality rate was maximum after 96 h (95 ± 6%). Mortality was reduced when treated with 25%, 50%, and 75% supernatant. At 1 × 107 mL−1 of spore suspension, we found reductions of 71.6 ± 3.3% nematode populations in the soil, 60.7 ± 2.2% from the root, and 63.6 ± 2.4% egg mass compared with the control in the pot experiment. The culture supernatant applied at the 10% level showed a maximum mean reduction of the nematode population in roots (72.4 ± 2.2%), soil (77.9 ± 2.5%), and egg masses (73.2 ± 1.5%), respectively. The presence of P. formosus MD12 in a soil environment could antagonize nematode parasites and improve soil amendment. The P. formosus MD12 strain showed good biocontrol ability against the root-knot nematode, M. incognita, under in vitro and green house experimental condition.
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Mohan S, Kiran Kumar K, Sutar V, Saha S, Rowe J, Davies KG. Plant Root-Exudates Recruit Hyperparasitic Bacteria of Phytonematodes by Altered Cuticle Aging: Implications for Biological Control Strategies. FRONTIERS IN PLANT SCIENCE 2020; 11:763. [PMID: 32582268 PMCID: PMC7296116 DOI: 10.3389/fpls.2020.00763] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 05/13/2020] [Indexed: 05/21/2023]
Abstract
Phytonematodes are globally important functional components of the belowground ecology in both natural and agricultural soils; they are a diverse group of which some species are economically important pests, and environmentally benign control strategies are being sought to control them. Using eco-evolutionary theory, we test the hypothesis that root-exudates of host plants will increase the ability of a hyperparasitic bacteria, Pasteuria penetrans and other closely related bacteria, to infect their homologous pest nematodes, whereas non-host root exudates will not. Plant root-exudates from good hosts, poor hosts and non-hosts were characterized by gas chromatography-mass spectrometry (GC/MS) and we explore their interaction on the attachment of the hyperparasitic bacterial endospores to homologous and heterologous pest nematode cuticles. Although GC/MS did not identify any individual compounds as responsible for changes in cuticle susceptibility to endospore adhesion, standardized spore binding assays showed that Pasteuria endospore adhesion decreased with nematode age, and that infective juveniles pre-treated with homologous host root-exudates reduced the aging process and increased attachment of endospores to the nematode cuticle, whereas non-host root-exudates did not. We develop a working model in which plant root exudates manipulate the nematode cuticle aging process, and thereby, through increased bacterial endospore attachment, increase bacterial infection of pest nematodes. This we suggest would lead to a reduction of plant-parasitic nematode burden on the roots and increases plant fitness. Therefore, by the judicious manipulation of environmental factors produced by the plant root and by careful crop rotation this knowledge can help in the development of environmentally benign control strategies.
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Affiliation(s)
- Sharad Mohan
- Division of Nematology, Indian Council of Agricultural Research, Indian Agricultural Research Institute, New Delhi, India
- *Correspondence: Sharad Mohan,
| | - K. Kiran Kumar
- Indian Council of Agricultural Research, Central Citrus Research Institute, Nagpur, India
| | - Vivek Sutar
- Division of Nematology, Indian Council of Agricultural Research, Indian Agricultural Research Institute, New Delhi, India
| | - Supradip Saha
- Division of Agricultural Chemicals, Indian Council of Agricultural Research, Indian Agricultural Research Institute, New Delhi, India
| | - Janet Rowe
- Plant Pathology and Microbiology, Rothamsted Research, Harpenden, United Kingdom
| | - Keith G. Davies
- Department of Biological and Environmental Sciences, University of Hertfordshire, Hatfield, United Kingdom
- Norwegian Institute of Bioeconomy Research, Ås, Norway
- Keith G. Davies,
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11
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Identification and Characterization of a Fatty Acid- and Retinoid-Binding Protein Gene ( Ar-far-1) from the Chrysanthemum Foliar Nematode, Aphelenchoides ritzemabosi. Int J Mol Sci 2019; 20:ijms20225566. [PMID: 31703422 PMCID: PMC6888133 DOI: 10.3390/ijms20225566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 10/28/2019] [Accepted: 11/04/2019] [Indexed: 12/04/2022] Open
Abstract
The chrysanthemum foliar nematode (CFN), Aphelenchoides ritzemabosi, is a migratory, plant-parasitic nematode that is widely distributed and infects the aboveground parts of many plants. The fatty acid- and retinoid-binding proteins (FAR) are nematode-specific proteins that are involved in the development, reproduction, and infection of nematodes and are secreted into the tissues to disrupt the plant defense reaction. In this study, we obtained the full-length sequence of the FAR gene (Ar-far-1) from CFN, which is 727 bp and includes a 546 bp ORF that encodes 181 amino acids. Ar-FAR-1 from CFN has the highest sequence similarity to Ab-FAR-1 from A. besseyi, and they are located within the same branch of the phylogenetic tree. Fluorescence-based ligand-binding analysis confirmed that recombinant Ar-FAR-1 was bound to fatty acids and retinol. Ar-far-1 mRNA was expressed in the muscle layer, intestine, female genital system, and egg of CFN, and more highly expressed in females than in males among the four developmental stages of CFN. We demonstrated that the reproduction number and infection capacity of CFN decreased significantly when Ar-far-1 was effectively silenced by in vitro RNAi. Ar-far-1 plays an important role in the development, reproduction, infectivity, and pathogenesis of CFN and may be used as an effective target gene for the control of CFN. The results provide meaningful data about the parasitic and pathogenic genes of CFN to study the interaction mechanism between plant-parasitic nematodes and hosts.
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Chang DZ, Serra L, Lu D, Mortazavi A, Dillman AR. A core set of venom proteins is released by entomopathogenic nematodes in the genus Steinernema. PLoS Pathog 2019; 15:e1007626. [PMID: 31042778 PMCID: PMC6513111 DOI: 10.1371/journal.ppat.1007626] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 05/13/2019] [Accepted: 02/07/2019] [Indexed: 11/26/2022] Open
Abstract
Parasitic helminths release molecular effectors into their hosts and these effectors can directly damage host tissue and modulate host immunity. Excreted/secreted proteins (ESPs) are one category of parasite molecular effectors that are critical to their success within the host. However, most studies of nematode ESPs rely on in vitro stimulation or culture conditions to collect the ESPs, operating under the assumption that in vitro conditions mimic actual in vivo infection. This assumption is rarely if ever validated. Entomopathogenic nematodes (EPNs) are lethal parasites of insects that produce and release toxins into their insect hosts and are a powerful model parasite system. We compared transcriptional profiles of individual Steinernema feltiae nematodes at different time points of activation under in vitro and in vivo conditions and found that some but not all time points during in vitro parasite activation have similar transcriptional profiles with nematodes from in vivo infections. These findings highlight the importance of experimental validation of ESP collection conditions. Additionally, we found that a suite of genes in the neuropeptide pathway were downregulated as nematodes activated and infection progressed in vivo, suggesting that these genes are involved in host-seeking behavior and are less important during active infection. We then characterized the ESPs of activated S. feltiae infective juveniles (IJs) using mass spectrometry and identified 266 proteins that are released by these nematodes. In comparing these ESPs with those previously identified in activated S. carpocapsae IJs, we identified a core set of 52 proteins that are conserved and present in the ESPs of activated IJs of both species. These core venom proteins include both tissue-damaging and immune-modulating proteins, suggesting that the ESPs of these parasites include both a core set of effectors as well as a specialized set, more adapted to the particular hosts they infect.
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Affiliation(s)
- Dennis Z. Chang
- Department of Nematology, University of California, Riverside, California, United States of America
| | - Lorrayne Serra
- Department of Developmental and Cell Biology, Center for Complex Biological Systems, University of California, Irvine, California, United States of America
| | - Dihong Lu
- Department of Nematology, University of California, Riverside, California, United States of America
| | - Ali Mortazavi
- Department of Developmental and Cell Biology, Center for Complex Biological Systems, University of California, Irvine, California, United States of America
| | - Adler R. Dillman
- Department of Nematology, University of California, Riverside, California, United States of America
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Manan A, Bazai ZA, Fan J, Yu H, Li L. The Nif3-Family Protein YqfO03 from Pseudomonas syringae MB03 Has Multiple Nematicidal Activities against Caenorhabditis elegans and Meloidogyne incognita. Int J Mol Sci 2018; 19:ijms19123915. [PMID: 30563288 PMCID: PMC6321441 DOI: 10.3390/ijms19123915] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 11/20/2018] [Accepted: 12/04/2018] [Indexed: 11/29/2022] Open
Abstract
The nematicidal activity of the common plant-pathogenic bacterium Pseudomonas syringae against certain nematodes has been recently identified, but little is known about its virulence factors. In the current study, predictive analysis of nematode-virulent factors in the genome of a P. syringae wild-type strain MB03 revealed a variety of factors with the potential to be pathogenic against nematodes. One of these virulence factors that was predicted with a high score, namely, YqfO03, was a protein with structural domains that are similar to the Nif3 superfamily. This protein was expressed and purified in Escherichia coli, and was investigated for nematicidal properties against the model nematode Caenorhabditis elegans and an agriculturally important pest Meloidogyne incognita. Our results showed that YqfO03 exhibits lethal activity toward C. elegans and M. incognita worms, and it also caused detrimental effects on the growth, brood size, and motility of C. elegans worms. However, C. elegans worms were able to defend themselves against YqfO03 via a physical defense response by avoiding contact with the protein. Discovery of the diverse nematicidal activities of YqfO03 provides new knowledge on the biological function of a bacterial Nif3-family protein and insight into the potential of this protein as a specific means of controlling agricultural nematode pests.
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Affiliation(s)
- Abdul Manan
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
- Center for Advance Studies in Vaccinology and Biotechnology, University of Baluchistan, Quetta 87300, Pakistan.
| | - Zahoor Ahmad Bazai
- Department of Botany, University of Baluchistan, Quetta 87300, Pakistan.
| | - Jin Fan
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Huafu Yu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Lin Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
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Phani V, Somvanshi VS, Shukla RN, Davies KG, Rao U. A transcriptomic snapshot of early molecular communication between Pasteuria penetrans and Meloidogyne incognita. BMC Genomics 2018; 19:850. [PMID: 30486772 PMCID: PMC6263062 DOI: 10.1186/s12864-018-5230-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 11/07/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Southern root-knot nematode Meloidogyne incognita (Kofoid and White, 1919), Chitwood, 1949 is a key pest of agricultural crops. Pasteuria penetrans is a hyperparasitic bacterium capable of suppressing the nematode reproduction, and represents a typical coevolved pathogen-hyperparasite system. Attachment of Pasteuria endospores to the cuticle of second-stage nematode juveniles is the first and pivotal step in the bacterial infection. RNA-Seq was used to understand the early transcriptional response of the root-knot nematode at 8 h post Pasteuria endospore attachment. RESULTS A total of 52,485 transcripts were assembled from the high quality (HQ) reads, out of which 582 transcripts were found differentially expressed in the Pasteuria endospore encumbered J2 s, of which 229 were up-regulated and 353 were down-regulated. Pasteuria infection caused a suppression of the protein synthesis machinery of the nematode. Several of the differentially expressed transcripts were putatively involved in nematode innate immunity, signaling, stress responses, endospore attachment process and post-attachment behavioral modification of the juveniles. The expression profiles of fifteen selected transcripts were validated to be true by the qRT PCR. RNAi based silencing of transcripts coding for fructose bisphosphate aldolase and glucosyl transferase caused a reduction in endospore attachment as compared to the controls, whereas, silencing of aspartic protease and ubiquitin coding transcripts resulted in higher incidence of endospore attachment on the nematode cuticle. CONCLUSIONS Here we provide evidence of an early transcriptional response by the nematode upon infection by Pasteuria prior to root invasion. We found that adhesion of Pasteuria endospores to the cuticle induced a down-regulated protein response in the nematode. In addition, we show that fructose bisphosphate aldolase, glucosyl transferase, aspartic protease and ubiquitin coding transcripts are involved in modulating the endospore attachment on the nematode cuticle. Our results add new and significant information to the existing knowledge on early molecular interaction between M. incognita and P. penetrans.
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Affiliation(s)
- Victor Phani
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Vishal S Somvanshi
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Rohit N Shukla
- Bionivid Technology Private Limited, 209, 4th Cross, Kasturi Nagar, Bangalore, India
| | - Keith G Davies
- Department of Biological and Environmental Sciences, University of Hertfordshire, Hatfield, UK. .,Division of Biotechnology and Plant Health, Norwegian Institute of Bioeconomy Research, Postboks 115 NO-1431, Ås, Norway.
| | - Uma Rao
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, India.
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Phani V, Shivakumara TN, Davies KG, Rao U. Knockdown of a mucin-like gene in Meloidogyne incognita (Nematoda) decreases attachment of endospores of Pasteuria penetrans to the infective juveniles and reduces nematode fecundity. MOLECULAR PLANT PATHOLOGY 2018; 19:2370-2383. [PMID: 30011135 PMCID: PMC6638177 DOI: 10.1111/mpp.12704] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 05/14/2018] [Accepted: 06/08/2018] [Indexed: 05/30/2023]
Abstract
Mucins are highly glycosylated polypeptides involved in many host-parasite interactions, but their function in plant-parasitic nematodes is still unknown. In this study, a mucin-like gene was cloned from Meloidogyne incognita (Mi-muc-1, 1125 bp) and characterized. The protein was found to be rich in serine and threonine with numerous O-glycosylation sites in the sequence. Quantitative real-time polymerase chain reaction (qRT-PCR) showed the highest expression in the adult female and in situ hybridization revealed the localization of Mi-muc-1 mRNA expression in the tail area in the region of the phasmid. Knockdown of Mi-muc-1 revealed a dual role: (1) immunologically, there was a significant decrease in attachment of Pasteuria penetrans endospores and a reduction in binding assays with human red blood cells (RBCs), suggesting that Mi-MUC-1 is a glycoprotein present on the surface coat of infective second-stage juveniles (J2s) and is involved in cellular adhesion to the cuticle of infective J2s; pretreatment of J2s with different carbohydrates indicated that the RBCs bind to J2 cuticle receptors different from those involved in the interaction of Pasteuria endospores with Mi-MUC-1; (2) the long-term effect of RNA interference (RNAi)-mediated knockdown of Mi-muc-1 led to a significant reduction in nematode fecundity, suggesting a possible function for this mucin as a mediator in the interaction between the nematode and the host plant.
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Affiliation(s)
- Victor Phani
- Division of NematologyICAR‐Indian Agricultural Research InstituteNew Delhi110012India
| | | | - Keith G Davies
- Department of Biological and Environmental SciencesUniversity of HertfordshireHatfieldAL10 9ABUnited Kingdom
- Norwegian Institute of Bioeconomy ResearchÅs115, 1431Norway
| | - Uma Rao
- Division of NematologyICAR‐Indian Agricultural Research InstituteNew Delhi110012India
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Phani V, Somvanshi VS, Rao U. Silencing of a Meloidogyne incognita selenium-binding protein alters the cuticular adhesion of Pasteuria penetrans endospores. Gene 2018; 677:289-298. [PMID: 30125659 DOI: 10.1016/j.gene.2018.08.058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 07/30/2018] [Accepted: 08/16/2018] [Indexed: 11/30/2022]
Abstract
Pasteuria penetrans is an endospore forming hyperparasitic bacterium of the plant-pathogenic root-knot nematode, Meloidogyne incognita. For successful parasitization, the first step is adherence of bacterial endospores onto the cuticle surface of nematode juveniles. The knowledge of molecular intricacies involved during this adherence is sparse. Here, we identified a M. incognita selenium-binding protein (Mi-SeBP-1) differentially expressed during the initial interaction of M. incognita and P. penetrans, and show that it is involved in modulating parasitic adhesion of bacterial endospores onto nematode cuticle. Selenium-binding proteins (SeBPs) are selenium associated proteins important for growth regulation, tumor prevention and modulation of oxidation/reduction in cells. Although reported to be present in several nematodes, the function of SeBPs is not known in Phylum Nematoda. In situ hybridization assay localized the Mi-SeBP-1 mRNA to the hypodermal cells. RNAi-mediated silencing of Mi-SeBP-1 significantly increased the adherence of P. penetrans endospores to the nematode juvenile cuticle. Silencing of Mi-SeBP-1 did not change the nematode's ability to parasitize plants and reproduction potential within the host. These results suggest that M. incognita Mi-SeBP-1 might be involved in altering the attachment of microbial pathogens on the nematode cuticle, but is not involved in nematode-host plant interaction. This is the first report for a function of SeBP in Phylum Nematoda.
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Affiliation(s)
- Victor Phani
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | | | - Uma Rao
- Division of Nematology, ICAR-Indian Agricultural Research Institute, New Delhi, India.
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