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Chang Q, Yang Y, Hong B, Zhao Y, Zhao M, Han S, Zhang F, Peng H, Peng D, Li Y. A variant of the venom allergen-like protein, DdVAP2, is required for the migratory endoparasitic plant nematode Ditylenchus destructor parasitism of plants. FRONTIERS IN PLANT SCIENCE 2023; 14:1322902. [PMID: 38152146 PMCID: PMC10751354 DOI: 10.3389/fpls.2023.1322902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 11/28/2023] [Indexed: 12/29/2023]
Abstract
The potato rot nematode, Ditylenchus destructor, poses a serious threat to numerous root and tuber crops, yet the functional characterization of effectors from this migratory endoparasitic plant nematode remains limited. Despite inhabiting distinct habitats, sedentary and migratory plant parasitic nematodes share the structurally conserved effectors, such as venom allergen-like proteins (VAPs). In this study, a variant of DdVAP2 was cloned from D. destructor. The transcription profile analysis revealed that DdVAP2 was higher expressed in D. destructor feeding on either potato or sweet potato compared to on fungus via qRT-PCR. And DdVAP2 was highly expressed at all life stages feeding on sweet potato, except for eggs. DdVAP2 was confirmed to be specifically expressed in the subventral esophageal glands of D. destructor through in situ hybridization assays. Combined with functional validation of the signal peptide of DdVAP2, it suggested that DdVAP2 could be secreted from nematode into host. Heterologous expression of DdVAP2 in Nicotiana benthamiana revealed that the protein localized in both cytosol and nuclei of plant cells. Knocking down DdVAP2 by RNAi in D. destructor resulted in infection and reproduction defects on plants. All the results suggest that DdVAP2 plays a crucial role in the interaction between D. destructor and plants by facilitating the nematode infection.
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Affiliation(s)
- Qing Chang
- Shaanxi Key Laboratory of Plant Nematology, Bio-Agriculture Institute of Shaanxi, Xi’an, China
| | - Yiwei Yang
- Shaanxi Key Laboratory of Plant Nematology, Bio-Agriculture Institute of Shaanxi, Xi’an, China
| | - Bo Hong
- Shaanxi Key Laboratory of Plant Nematology, Bio-Agriculture Institute of Shaanxi, Xi’an, China
| | - Yanqun Zhao
- Yulin Agricultural Technology Service Center, Yulin, China
| | - Mengxin Zhao
- Shaanxi Key Laboratory of Plant Nematology, Bio-Agriculture Institute of Shaanxi, Xi’an, China
| | - Shanshan Han
- Shaanxi Key Laboratory of Plant Nematology, Bio-Agriculture Institute of Shaanxi, Xi’an, China
| | - Feng Zhang
- Shaanxi Key Laboratory of Plant Nematology, Bio-Agriculture Institute of Shaanxi, Xi’an, China
| | - Huan Peng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Deliang Peng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yingmei Li
- Shaanxi Key Laboratory of Plant Nematology, Bio-Agriculture Institute of Shaanxi, Xi’an, China
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Wang C, Zhuge J, Tang S, Zhou X, Zhou L, Guo K. Comparative effects of two in situ hybridization methods for the pinewood nematode ( Bursaphelenchus xylophilus). Front Microbiol 2023; 14:1234895. [PMID: 38098656 PMCID: PMC10720641 DOI: 10.3389/fmicb.2023.1234895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 10/18/2023] [Indexed: 12/17/2023] Open
Abstract
The gene localization technique of Bursaphelenchus xylophilus (pinewood nematode, PWN) is used for study gene expression in PWNs. Two in situ hybridization methods, namely, whole-mount in situ hybridization and the cut-off method are used widely. To compare the effects of these two in situ hybridization methods, the present study investigated the patterns of two functional genes expression in PWNs. The Bx-vap-2 gene (GenBank accession number: OR228482), related to pathogenicity, and the fem-2 gene (GenBank accession number: OR228481), related to sex determination, were selected to map related genes in the whole-mount and amputated PWNs at different ages using these in situ hybridization methods. Based on the overall statistical comparison, we found that compared to the cut-off method, the whole-mount method exhibited higher staining rates and correct staining rates for the fem-2 gene and Bx-vap-2 gene. However, considering the correct staining aspect, the cut-off method yielded better staining effects on pinewood nematode sections than the whole-mount method, with clearer hybridization signal locations and less non-specific staining. In other words, the cut-off method demonstrated more precise gene localization. Both methods are applicable for gene localization, but considering the overall staining pattern, analysis of experimental results, and comprehensive experimental operations, we believe that the whole-mount method is more suitable for gene localization and expression analysis of development-related genes in pinewood nematodes. This is because intact pinewood nematodes are better suited for showcasing the continuous developmental process of development-related genes. On the other hand, considering the experimental time, accuracy of staining site, and the amount of non-specific staining, the cut-off method is more suitable for disease-related genes. Additionally, to achieve better performance, the cut-off method can be selectively applied to samples during the experimental process.
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Affiliation(s)
- Chunyu Wang
- School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, China
| | - Junhao Zhuge
- School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, China
| | - Siqi Tang
- School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, China
| | - Xiang Zhou
- National Joint Local Engineering Laboratory for High-Efficient Preparation of Biopesticide, Changsha, China
| | - Lifeng Zhou
- School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, China
| | - Kai Guo
- School of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, China
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3
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Ding X, Zhao R, Dai Y, Zhang Y, Lin S, Ye J. Comprehensive Analysis of Copy Number Variations on Glycoside Hydrolase 45 Genes among Different Bursaphelenchus xylophilus Strains. Int J Mol Sci 2022; 23:ijms232315323. [PMID: 36499649 PMCID: PMC9735991 DOI: 10.3390/ijms232315323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 11/29/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022] Open
Abstract
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.
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Affiliation(s)
- Xiaolei Ding
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing 210037, China
- Correspondence:
| | - Ruiwen Zhao
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing 210037, China
| | - Yonglin Dai
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Yue Zhang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing 210037, China
| | - Sixi Lin
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing 210037, China
| | - Jianren Ye
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing 210037, China
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Ding X, Guo Y, Ye J, Wu X, Lin S, Chen F, Zhu L, Huang L, Song X, Zhang Y, Dai L, Xi X, Huang J, Wang K, Fan B, Li D. Population differentiation and epidemic tracking of Bursaphelenchus xylophilus in China based on chromosome-level assembly and whole-genome sequencing data. PEST MANAGEMENT SCIENCE 2022; 78:1213-1226. [PMID: 34839581 PMCID: PMC9300093 DOI: 10.1002/ps.6738] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 11/09/2021] [Accepted: 11/28/2021] [Indexed: 05/13/2023]
Abstract
BACKGROUND Bursaphelenchus xylophilus, the pinewood nematode, kills millions of pine trees worldwide every year, and causes enormous economic and ecological losses. Despite extensive research on population variation, there is little understanding of the population-wide variation spectrum in China. RESULTS We sequenced an inbred B. xylophilus strain using Pacbio+Illumina+Bionano+Hi-C and generated a chromosome-level assembly (AH1) with six chromosomes of 77.1 Mb (chromosome N50: 12 Mb). The AH1 assembly shows very high continuity and completeness, and contains novel genes with potentially important functions compared with previous assemblies. Subsequently, we sequenced 181 strains from China and the USA and found ~7.8 million single nucleotide polymorphisms (SNPs). Analysis shows that the B. xylophilus population in China can be divided into geographically bounded subpopulations with severe cross-infection and potential migrations. In addition, distribution of B. xylophilus is dominated by temperature zones while geographically associated SNPs are mainly located on adaptation related GPCR gene families, suggesting the nematode has been evolving to adapt to different temperatures. A machine-learning based epidemic tracking method has been established to predict their geographical origins, which can be applied to any other species. CONCLUSION Our study provides the community with the first high-quality chromosome-level assembly which includes a comprehensive catalogue of genetic variations. It provides insights into population structure and effective tracking method for this invasive species, which facilitates future studies to address a variety of applied, genomic and evolutionary questions in B. xylophilus as well as related species.
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Affiliation(s)
- Xiaolei Ding
- Co‐Innovation Center for Sustainable Forestry in Southern China, College of ForestryNanjing Forestry UniversityNanjingChina
- Jiangsu Key Laboratory for Prevention and Management of Invasive SpeciesNanjingChina
- Zilkha Neurogenetic Institute, University of Southern CaliforniaLos AngelesCAUSA
| | - Yunfei Guo
- Zilkha Neurogenetic Institute, University of Southern CaliforniaLos AngelesCAUSA
- Department of Preventive MedicineUniversity of Southern CaliforniaLos AngelesCAUSA
| | - Jianren Ye
- Co‐Innovation Center for Sustainable Forestry in Southern China, College of ForestryNanjing Forestry UniversityNanjingChina
- Jiangsu Key Laboratory for Prevention and Management of Invasive SpeciesNanjingChina
| | - Xiaoqin Wu
- Co‐Innovation Center for Sustainable Forestry in Southern China, College of ForestryNanjing Forestry UniversityNanjingChina
- Jiangsu Key Laboratory for Prevention and Management of Invasive SpeciesNanjingChina
| | - Sixi Lin
- Co‐Innovation Center for Sustainable Forestry in Southern China, College of ForestryNanjing Forestry UniversityNanjingChina
- Jiangsu Key Laboratory for Prevention and Management of Invasive SpeciesNanjingChina
| | - Fengmao Chen
- Co‐Innovation Center for Sustainable Forestry in Southern China, College of ForestryNanjing Forestry UniversityNanjingChina
- Jiangsu Key Laboratory for Prevention and Management of Invasive SpeciesNanjingChina
| | - Lihua Zhu
- Co‐Innovation Center for Sustainable Forestry in Southern China, College of ForestryNanjing Forestry UniversityNanjingChina
- Jiangsu Key Laboratory for Prevention and Management of Invasive SpeciesNanjingChina
| | - Lin Huang
- Co‐Innovation Center for Sustainable Forestry in Southern China, College of ForestryNanjing Forestry UniversityNanjingChina
- Jiangsu Key Laboratory for Prevention and Management of Invasive SpeciesNanjingChina
| | - Xiaofeng Song
- Department of Biomedical EngineeringNanjing University of Aeronautics and AstronauticsNanjingChina
| | - Yi Zhang
- Co‐Innovation Center for Sustainable Forestry in Southern China, College of ForestryNanjing Forestry UniversityNanjingChina
- Jiangsu Key Laboratory for Prevention and Management of Invasive SpeciesNanjingChina
| | - Ling Dai
- Co‐Innovation Center for Sustainable Forestry in Southern China, College of ForestryNanjing Forestry UniversityNanjingChina
- Jiangsu Key Laboratory for Prevention and Management of Invasive SpeciesNanjingChina
| | - Xiaotong Xi
- Co‐Innovation Center for Sustainable Forestry in Southern China, College of ForestryNanjing Forestry UniversityNanjingChina
- Jiangsu Key Laboratory for Prevention and Management of Invasive SpeciesNanjingChina
| | - Jinsi Huang
- Co‐Innovation Center for Sustainable Forestry in Southern China, College of ForestryNanjing Forestry UniversityNanjingChina
- Jiangsu Key Laboratory for Prevention and Management of Invasive SpeciesNanjingChina
| | - Kai Wang
- Zilkha Neurogenetic Institute, University of Southern CaliforniaLos AngelesCAUSA
- Department of Preventive MedicineUniversity of Southern CaliforniaLos AngelesCAUSA
- Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children's Hospital of PhiladelphiaPhiladelphiaPAUSA
- Department of Pathology and Laboratory MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Ben Fan
- Co‐Innovation Center for Sustainable Forestry in Southern China, College of ForestryNanjing Forestry UniversityNanjingChina
- Jiangsu Key Laboratory for Prevention and Management of Invasive SpeciesNanjingChina
| | - De‐Wei Li
- The Connecticut Agricultural Experiment Station Valley LaboratoryWindsorCTUSA
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Li J, Xu C, Yang S, Chen C, Tang S, Wang J, Xie H. A Venom Allergen-Like Protein, RsVAP, the First Discovered Effector Protein of Radopholus similis That Inhibits Plant Defense and Facilitates Parasitism. Int J Mol Sci 2021; 22:4782. [PMID: 33946385 PMCID: PMC8125365 DOI: 10.3390/ijms22094782] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 04/13/2021] [Accepted: 04/28/2021] [Indexed: 12/16/2022] Open
Abstract
Radopholus similis is a migratory endoparasitic nematode that is extremely harmful to host plants. Venom allergen-like proteins (VAPs) are members of the cysteine-rich secretory protein family that are widely present in plants and animals. In this study, we cloned a VAP gene from R. similis, designated as RsVAP. RsVAP contains an open reading frame of 1089 bp encoding 362 amino acids. RsVAP is specifically expressed in the esophageal gland, and the expression levels of RsVAP are significantly higher in juveniles than in other life stages of R. similis. This expression pattern of RsVAP was consistent with the biological characteristics of juveniles of R. similis, which have the ability of infection and are the main infection stages of R. similis. The pathogenicity and reproduction rate of R. similis in tomato was significantly attenuated after RsVAP was silenced. In tobacco leaves transiently expressing RsVAP, the pathogen-associated molecular pattern-triggered immunity (PTI) induced by a bacterial flagellin fragment (flg22) was inhibited, while the cell death induced by two sets of immune elicitors (BAX and Gpa2/RBP-1) was repressed. The RsVAP-interacting, ras-related protein RABA1d (LeRabA1d) was identified in tomato hosts by yeast two-hybrid and co-immunoprecipitation assays. RsVAP may interact with LeRabA1d to affect the host defense response, which in turn facilitates nematode infection. This study provides the first evidence for the inhibition of plant defense response by a VAP from migratory plant-parasitic nematodes, and, for the first time, the target protein of R. similis in its host was identified.
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Affiliation(s)
| | | | | | | | | | | | - Hui Xie
- Research Center of Nematodes of Plant Quarantine, Laboratory of Plant Nematology, Department of Plant Pathology/Guangdong Province Key Laboratory of Microbial Signals and Disease Control, College of Plant Protection, South China Agricultural University, Guangzhou 510642, China; (J.L.); (C.X.); (S.Y.); (C.C.); (S.T.); (J.W.)
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Kirino H, Yoshimoto K, Shinya R. Thaumatin-like proteins and a cysteine protease inhibitor secreted by the pine wood nematode Bursaphelenchus xylophilus induce cell death in Nicotiana benthamiana. PLoS One 2020; 15:e0241613. [PMID: 33125444 PMCID: PMC7598465 DOI: 10.1371/journal.pone.0241613] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 10/19/2020] [Indexed: 12/29/2022] Open
Abstract
Pine wilt disease (PWD) is an infectious disease of pines that typically kills affected trees. The causal pathogen of PWD is the pine wood nematode (PWN), Bursaphelenchus xylophilus. Understanding of the disease has advanced in recent years through the use of a highly sensitive proteomics procedure and whole genome sequence analysis; in combination, these approaches have enabled identification of proteins secreted by PWNs. However, the roles of these proteins during the onset of parasitism have not yet been elucidated. In this study, we used a leaf-disk assay based on transient overexpression in Nicotiana benthamiana to allow functional screening of 10 candidate pathogenic proteins secreted by PWNs. These proteins were selected based on previous secretome and RNA-seq analyses. We found that five molecules induced significant cell death in tobacco plants relative to a GFP-only control. Three of these proteins (Bx-TH1, Bx-TH2, and Bx-CPI) may have a role in molecular mimicry and likely make important contributions to inducing hypersensitive responses in host plants.
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Affiliation(s)
- Haru Kirino
- School of Agriculture, Meiji University, Kawasaki-shi, Kanagawa, Japan
| | - Kohki Yoshimoto
- School of Agriculture, Meiji University, Kawasaki-shi, Kanagawa, Japan
| | - Ryoji Shinya
- School of Agriculture, Meiji University, Kawasaki-shi, Kanagawa, Japan
- JST PRESTO, Kanagawa, Japan
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Xue Q, Wu XQ, Zhang WJ, Deng LN, Wu MM. Cathepsin L-like Cysteine Proteinase Genes Are Associated with the Development and Pathogenicity of Pine Wood Nematode, Bursaphelenchus xylophilus. Int J Mol Sci 2019; 20:E215. [PMID: 30626082 PMCID: PMC6337200 DOI: 10.3390/ijms20010215] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 01/01/2019] [Indexed: 01/01/2023] Open
Abstract
The pine wood nematode (PWN), Bursaphelenchus xylophilus, is the pathogen of pine wilt disease (PWD), resulting in huge losses in pine forests. However, its pathogenic mechanism remains unclear. The cathepsin L-like cysteine proteinase (CPL) genes are multifunctional genes related to the parasitic abilities of plant-parasitic nematodes, but their functions in PWN remain unclear. We cloned three cpl genes of PWN (Bx-cpls) by rapid amplification of cDNA ends (RACE) and analyzed their characteristics using bioinformatic methods. The tissue specificity of cpl gene of PWN (Bx-cpl) was studied using in situ mRNA hybridization (ISH). The functions of Bx-cpls in development and pathogenicity were investigated using real-time quantitative PCR (qPCR) and RNA interference (RNAi). The results showed that the full-length cDNAs of Bx-cpl-1, Bx-cpl-2, and Bx-cpl-3 were 1163 bp, 1305 bp, and 1302 bp, respectively. Bx-cpls could accumulate specifically in the egg, intestine, and genital system of PWN. During different developmental stages of PWN, the expression of Bx-cpls in the egg stage was highest. After infection, the expression levels of Bx-cpls increased and reached their highest at the initial stage of PWD, then declined gradually. The silencing of Bx-cpl could reduce the feeding, reproduction, and pathogenicity of PWN. These results revealed that Bx-cpls play multiple roles in the development and pathogenic processes of PWN.
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Affiliation(s)
- Qi Xue
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China.
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing Forestry University, Nanjing 210037, China.
| | - Xiao-Qin Wu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China.
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing Forestry University, Nanjing 210037, China.
| | - Wan-Jun Zhang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China.
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing Forestry University, Nanjing 210037, China.
| | - Li-Na Deng
- Yancheng Institute of Technology, School of Ocean and Biological Engineering, Yancheng 224051, China.
| | - Miao-Miao Wu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China.
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing Forestry University, Nanjing 210037, China.
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Fernandes RS, Barbosa TC, Barbosa MMF, Miyasato PA, Nakano E, Leite LCC, Farias LP. Stage and tissue expression patterns of Schistosoma mansoni venom allergen-like proteins SmVAL 4, 13, 16 and 24. Parasit Vectors 2017; 10:223. [PMID: 28482920 PMCID: PMC5422958 DOI: 10.1186/s13071-017-2144-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 04/19/2017] [Indexed: 11/20/2022] Open
Abstract
Background Schistosoma mansoni venom allergen-like protein (SmVAL) is a gene family composed of 29 members divided into group 1 encoding proteins potentially secreted, and group 2 encoding intracellular components. Some members were found to be upregulated in the transition of germ ball - cercariae - day 3 schistosomula, suggesting that group 1 SmVAL proteins are associated with the invasion of the human host, although their functions are not completely established. Recently, we have described the localization of SmVAL7 (group 1) and SmVAL6 (group 2) transcripts in the oesophageal gland and in the oral and ventral suckers of adult parasites, respectively. The expression patterns of the two genes suggest that SmVAL7 protein plays a role in the blood-feeding process while SmVAL6 is associated with the parasite attachment and movement in the vasculature. In this way, searching for additional secreted SmVAL proteins that could be involved in key processes from skin penetration to the beginning of blood-feeding, we investigated the tissue localization of SmVAL4, 13, 16 and 24 by whole-mount in situ hybridization (WISH). Results We report here the localization of group 1 SmVAL4 and 24 transcripts in the pre-acetabular glands of developing germ balls. Time course experiments of in vitro cultured schistosomula after cercariae transformation demonstrated that SmVAL4 protein is secreted during the first 3 h of in vitro culture, correlating with the emptying of acetabular glands as documented by confocal microscopy. In addition, the localization of SmVAL13 transcripts in adult male anterior oesophageal gland suggests that the respective protein may be involved in the first steps of the blood-feeding process. SmVAL16 was localized close to the neural ganglia and requires further investigation. Conclusions Our findings demonstrate that SmVAL proteins have localizations that place them in strategic positions to be considered as potential vaccine candidates as some members are exposed to interaction with the immune system and may participate in key processes of mammalian invasion and parasitism establishment. Electronic supplementary material The online version of this article (doi:10.1186/s13071-017-2144-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Rafaela Sachetto Fernandes
- Centro de Biotecnologia, Instituto Butantan, Av. Vital Brasil, 1500, São Paulo, SP, Brazil.,Programa de Pós-Graduação Interunidades em Biotecnologia, Universidade de São Paulo, São Paulo, SP, Brazil
| | | | - Mayra Mara Ferrari Barbosa
- Centro de Biotecnologia, Instituto Butantan, Av. Vital Brasil, 1500, São Paulo, SP, Brazil.,Programa de Pós-Graduação Interunidades em Biotecnologia, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Patrícia Aoki Miyasato
- Laboratório de Parasitologia, Instituto Butantan, Av. Vital Brasil, 1500, São Paulo, SP, Brazil
| | - Eliana Nakano
- Laboratório de Parasitologia, Instituto Butantan, Av. Vital Brasil, 1500, São Paulo, SP, Brazil
| | | | - Leonardo Paiva Farias
- Centro de Biotecnologia, Instituto Butantan, Av. Vital Brasil, 1500, São Paulo, SP, Brazil. .,Present Address: Instituto Gonçalo Moniz, Fundação Oswaldo Cruz (FIOCRUZ), Salvador, BA, Brazil.
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9
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Espada M, Silva AC, Eves van den Akker S, Cock PJA, Mota M, Jones JT. Identification and characterization of parasitism genes from the pinewood nematode Bursaphelenchus xylophilus reveals a multilayered detoxification strategy. MOLECULAR PLANT PATHOLOGY 2016; 17:286-95. [PMID: 25981957 PMCID: PMC6638532 DOI: 10.1111/mpp.12280] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The migratory endoparasitic nematode Bursaphelenchus xylophilus, which is the causal agent of pine wilt disease, has phytophagous and mycetophagous phases during its life cycle. This highly unusual feature distinguishes it from other plant-parasitic nematodes and requires profound changes in biology between modes. During the phytophagous stage, the nematode migrates within pine trees, feeding on the contents of parenchymal cells. Like other plant pathogens, B. xylophilus secretes effectors from pharyngeal gland cells into the host during infection. We provide the first description of changes in the morphology of these gland cells between juvenile and adult life stages. Using a comparative transcriptomics approach and an effector identification pipeline, we identify numerous novel parasitism genes which may be important for the mediation of interactions of B. xylophilus with its host. In-depth characterization of all parasitism genes using in situ hybridization reveals two major categories of detoxification proteins, those specifically expressed in either the pharyngeal gland cells or the digestive system. These data suggest that B. xylophilus incorporates effectors in a multilayer detoxification strategy in order to protect itself from host defence responses during phytophagy.
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Affiliation(s)
- Margarida Espada
- NemaLab/ICAAM-Instituto de Ciências Agrárias e Ambientais Mediterrânicas, Universidade de Évora, Núcleo da Mitra, Ap. 94, 7002-554, Évora, Portugal
- Cell and Molecular Sciences Group/Information and Computer Sciences Group (PJAC), The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
| | - Ana Cláudia Silva
- NemaLab/ICAAM-Instituto de Ciências Agrárias e Ambientais Mediterrânicas, Universidade de Évora, Núcleo da Mitra, Ap. 94, 7002-554, Évora, Portugal
- Cell and Molecular Sciences Group/Information and Computer Sciences Group (PJAC), The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
- Biology Department, University of Gent, KL Ledeganckstraat 35, B9000, Gent, Belgium
| | | | - Peter J A Cock
- Cell and Molecular Sciences Group/Information and Computer Sciences Group (PJAC), The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
| | - Manuel Mota
- NemaLab/ICAAM-Instituto de Ciências Agrárias e Ambientais Mediterrânicas, Universidade de Évora, Núcleo da Mitra, Ap. 94, 7002-554, Évora, Portugal
| | - John T Jones
- Cell and Molecular Sciences Group/Information and Computer Sciences Group (PJAC), The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
- Biology Department, University of Gent, KL Ledeganckstraat 35, B9000, Gent, Belgium
- School of Biology, University of St Andrews, North Haugh, St Andrews, KY16 9TZ, UK
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10
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Chi Y, Wang X, Le X, Ju Y, Guan T, Li H. Exposure to double-stranded RNA mediated by tobacco rattle virus leads to transcription up-regulation of effector gene Mi-vap-2 from Meloidogyne incognita and promotion of pathogenicity in progeny. Int J Parasitol 2016; 46:105-13. [PMID: 26545953 DOI: 10.1016/j.ijpara.2015.09.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 09/17/2015] [Indexed: 10/22/2022]
Abstract
Meloidogyne spp. are economically important plant parasites and cause enormous damage to agriculture world-wide. These nematodes use secreted effectors which modify host cells, allowing them to obtain the nutrients required for growth and development. A better understanding of the roles of effectors in nematode parasitism is critical for understanding the mechanisms of nematode-host interactions. In this study, Mi-vap-2 of Meloidogyne incognita, a gene encoding a venom allergen-like protein, was targeted by RNA interference mediated by the tobacco rattle virus. Unexpectedly, compared with a wild type line, a substantial up-regulation of Mi-vap-2 transcript was observed in juveniles collected at 7 days p.i. from Nicotiana benthamiana agroinfiltrated with TRV::vap-2. This up-regulation of the targeted transcript did not impact development of females or the production of galls, nor the number of females on the TRV::vap-2 line. In a positive control line, the transcript of Mi16D10 was knocked down in juveniles from the TRV::16D10 line at 7 days p.i., resulting in a significant inhibition of nematode development. The up-regulation of Mi-vap-2 triggered by TRV-RNAi was inherited by the progeny of the nematodes exposed to double-stranded RNA. Meanwhile, a substantial increase in Mi-VAP-2 expression in those juvenile progeny was revealed by ELISA. This caused an increase in the number of galls (71.2%) and females (84.6%) produced on seedlings of N. benthamiana compared with the numbers produced by control nematodes. Up-regulation of Mi-vap-2 and its encoded protein therefore enhanced pathogenicity of the nematodes, suggesting that Mi-vap-2 may be required for successful parasitism during the early parasitic stage of M. incognita.
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Affiliation(s)
- Yuankai Chi
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Xuan Wang
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Xiuhu Le
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Yuliang Ju
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Tinglong Guan
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, PR China
| | - Hongmei Li
- Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, PR China.
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11
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Nawaratna SSK, Gobert GN, Willis C, Chuah C, McManus DP, Jones MK. Transcriptional profiling of the oesophageal gland region of male worms of Schistosoma mansoni. Mol Biochem Parasitol 2014; 196:82-9. [PMID: 25149559 DOI: 10.1016/j.molbiopara.2014.08.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 08/04/2014] [Accepted: 08/04/2014] [Indexed: 11/24/2022]
Abstract
The intestinal tract of schistosomes opens at the mouth and leads into the foregut or oesophageal region that is lined with syncytium continuous with the apical cytoplasm of the tegument. The oesophagus is surrounded by a specialised gland, the oesophageal gland. This gland releases materials into the lumen of the oesophagus and the region is thought to initiate the lysis of erythrocytes and neutralisation of immune effectors of the host. The oesophageal region is present in the early invasive schistosomulum, a stage potentially targetable by anti-schistosome vaccines. We used a 44k oligonucleotide microarray to identify highly up-regulated genes in microdissected frozen sections of the oesophageal gland of male worms of S. mansoni. We show that 122 genes were up-regulated 2-fold or higher in the oesophageal gland compared with a whole male worm tissue control. The enriched genes included several associated with lipid metabolism and transmembrane transport as well as some micro-exon genes. Since the oesophageal gland is important in the initiation of digestion and the fact that it develops early after invasion of the mammalian host, further study of selected highly up-regulated functionally important genes in this tissue may reveal new anti-schistosome intervention targets for schistosomiasis control.
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Affiliation(s)
- Sujeevi S K Nawaratna
- School of Veterinary Sciences, The University of Queensland, Gatton Campus, Gatton, Qld 4343, Australia; QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Qld 4006, Australia.
| | - Geoffrey N Gobert
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Qld 4006, Australia
| | - Charlene Willis
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Qld 4006, Australia
| | - Candy Chuah
- School of Veterinary Sciences, The University of Queensland, Gatton Campus, Gatton, Qld 4343, Australia; QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Qld 4006, Australia; School of Medical Sciences, Universiti Sains Malaysia, 16150 Kelantan, Malaysia
| | - Donald P McManus
- QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Qld 4006, Australia
| | - Malcolm K Jones
- School of Veterinary Sciences, The University of Queensland, Gatton Campus, Gatton, Qld 4343, Australia; QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, Qld 4006, Australia
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12
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Screening and functional analysis of the peroxiredoxin specifically expressed in Bursaphelenchus xylophilus--the causative agent of pine wilt disease. Int J Mol Sci 2014; 15:10215-32. [PMID: 24918285 PMCID: PMC4100149 DOI: 10.3390/ijms150610215] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 05/25/2014] [Accepted: 05/26/2014] [Indexed: 12/18/2022] Open
Abstract
The pine wood nematode, Bursaphelenchus xylophilus, is the causal agent of pine wilt disease. Accurately differentiating B. xylophilus from other nematodes species, especially its related species B. mucronatus, is important for pine wood nematode detection. Thus, we attempted to identify a specific protein in the pine wood nematode using proteomics technology. Here, we compared the proteomes of B. xylophilus and B. mucronatus using Two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization-time-of-flight/time-of-flight (MALDI-TOF/TOF-MS) technologies. In total, 15 highly expressed proteins were identified in B. xylophilus compared with B. mucronatus. Subsequently, the specificity of the proteins identified was confirmed by PCR using the genomic DNA of other nematode species. Finally, a gene encoding a specific protein (Bx-Prx) was obtained. This gene was cloned and expressed in E. coli. The in situ hybridisation pattern of Bx-Prx showed that it was expressed strongly in the tail of B. xylophilus. RNAi was used to assess the function of Bx-Prx, the results indicated that the gene was associated with the reproduction and pathogenicity of B. xylophilus. This discovery provides fundamental information for identifying B. xylophilus via a molecular approach. Moreover, the purified recombinant protein has potential as a candidate diagnostic antigen of pine wilt disease, which may lead to a new immunological detection method for the pine wood nematode.
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13
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Figueiredo J, Simões MJ, Gomes P, Barroso C, Pinho D, Conceição L, Fonseca L, Abrantes I, Pinheiro M, Egas C. Assessment of the geographic origins of pinewood nematode isolates via single nucleotide polymorphism in effector genes. PLoS One 2013; 8:e83542. [PMID: 24391785 PMCID: PMC3877046 DOI: 10.1371/journal.pone.0083542] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 11/05/2013] [Indexed: 11/18/2022] Open
Abstract
The pinewood nematode, Bursaphelenchus xylophilus, is native to North America but it only causes damaging pine wilt disease in those regions of the world where it has been introduced. The accurate detection of the species and its dispersal routes are thus essential to define effective control measures. The main goals of this study were to analyse the genetic diversity among B. xylophilus isolates from different geographic locations and identify single nucleotide polymorphism (SNPs) markers for geographic origin, through a comparative transcriptomic approach. The transcriptomes of seven B. xylophilus isolates, from Continental Portugal (4), China (1), Japan (1) and USA (1), were sequenced in the next generation platform Roche 454. Analysis of effector gene transcripts revealed inter-isolate nucleotide diversity that was validated by Sanger sequencing in the genomic DNA of the seven isolates and eight additional isolates from different geographic locations: Madeira Island (2), China (1), USA (1), Japan (2) and South Korea (2). The analysis identified 136 polymorphic positions in 10 effector transcripts. Pairwise comparison of the 136 SNPs through Neighbor-Joining and the Maximum Likelihood methods and 5-mer frequency analysis with the alignment-independent bilinear multivariate modelling approach correlated the SNPs with the isolates geographic origin. Furthermore, the SNP analysis indicated a closer proximity of the Portuguese isolates to the Korean and Chinese isolates than to the Japanese or American isolates. Each geographic cluster carried exclusive alleles that can be used as SNP markers for B. xylophilus isolate identification.
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Affiliation(s)
- Joana Figueiredo
- Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Maria José Simões
- Genoinseq, Next Generation Sequencing Unit, Biocant, Cantanhede, Portugal
| | - Paula Gomes
- Genoinseq, Next Generation Sequencing Unit, Biocant, Cantanhede, Portugal
| | - Cristina Barroso
- Genoinseq, Next Generation Sequencing Unit, Biocant, Cantanhede, Portugal
| | - Diogo Pinho
- Genoinseq, Next Generation Sequencing Unit, Biocant, Cantanhede, Portugal
| | - Luci Conceição
- IMAR-CMA, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Luís Fonseca
- IMAR-CMA, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Isabel Abrantes
- IMAR-CMA, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Miguel Pinheiro
- Genoinseq, Next Generation Sequencing Unit, Biocant, Cantanhede, Portugal
| | - Conceição Egas
- Genoinseq, Next Generation Sequencing Unit, Biocant, Cantanhede, Portugal
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14
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Shinya R, Morisaka H, Kikuchi T, Takeuchi Y, Ueda M, Futai K. Secretome Analysis of the Pine Wood Nematode Bursaphelenchus xylophilus Reveals the Tangled Roots of Parasitism and Its Potential for Molecular Mimicry. PLoS One 2013; 8:e67377. [PMID: 23805310 PMCID: PMC3689755 DOI: 10.1371/journal.pone.0067377] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 05/16/2013] [Indexed: 01/12/2023] Open
Abstract
Since it was first introduced into Asia from North America in the early 20(th) century, the pine wood nematode Bursaphelenchus xylophilus has caused the devastating forest disease called pine wilt. The emerging pathogen spread to parts of Europe and has since been found as the causal agent of pine wilt disease in Portugal and Spain. In 2011, the entire genome sequence of B. xylophilus was determined, and it allowed us to perform a more detailed analysis of B. xylophilus parasitism. Here, we identified 1,515 proteins secreted by B. xylophilus using a highly sensitive proteomics method combined with the available genomic sequence. The catalogue of secreted proteins contained proteins involved in nutrient uptake, migration, and evasion from host defenses. A comparative functional analysis of the secretome profiles among parasitic nematodes revealed a marked expansion of secreted peptidases and peptidase inhibitors in B. xylophilus via gene duplication and horizontal gene transfer from fungi and bacteria. Furthermore, we showed that B. xylophilus secreted the potential host mimicry proteins that closely resemble the host pine's proteins. These proteins could have been acquired by host-parasite co-evolution and might mimic the host defense systems in susceptible pine trees during infection. This study contributes to an understanding of their unique parasitism and its tangled roots, and provides new perspectives on the evolution of plant parasitism among nematodes.
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Affiliation(s)
- Ryoji Shinya
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
- College of Bioscience and Biotechnology, Chubu University, Kasugai, Japan
| | | | - Taisei Kikuchi
- Forestry and Forest Products Research Institute, Tsukuba, Japan
| | - Yuko Takeuchi
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Mitsuyoshi Ueda
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Kazuyoshi Futai
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
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15
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Cloning and molecular analysis of the aspartic protease Sc-ASP110 gene transcript in Steinernema carpocapsae. Parasitology 2013; 140:1158-67. [PMID: 23731543 DOI: 10.1017/s0031182013000577] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Many protease genes have previously been shown to be involved in parasitism and in the development of Steinernema carpocapsae, including a gene predicted to encode an aspartic protease, Sc-ASP110, which was cloned and was analysed in this study. A cDNA encoding Sc-ASP110 was cloned based on an expressed sequence tag (EST) fragment from our EST library. The full-length cDNA of Sc-ASP110 consists of 1112 nucleotides with a catalytic aspartic domain (aa18-337). The putative 341 amino acid residues have a calculated molecular mass of 37·1 kDa and a theoretical pI of 4·7. BLASTp analysis of the Sc-ASP110 amino acid sequence showed 45-77% amino acid sequence identity to parasitic and non-parasitic nematode aspartic proteases. An expression analysis showed that the sc-asp110 gene was upregulated during the late parasitic stage, L4, and 24 h after induction of in vitro nematodes. A sequence comparison revealed that Sc-ASP110 was a member of an aspartic protease family; additionally, a phylogenetic analysis indicated that Sc-ASP110 was clustered with the closely related nematode Steinernema feltiae. In situ hybridization showed that sc-asp110 was expressed in the body walls of dorsal cells. The upregulated Sc-ASP110 expression revealed that this protease could play a role in the late parasitic process. In this study, we have cloned and analysed the gene transcript of Sc-ASP110 in S. carpocapsae.
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16
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Shinya R, Morisaka H, Takeuchi Y, Futai K, Ueda M. Making headway in understanding pine wilt disease: what do we perceive in the postgenomic era? J Biosci Bioeng 2013; 116:1-8. [PMID: 23474098 DOI: 10.1016/j.jbiosc.2013.01.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 12/13/2012] [Accepted: 01/10/2013] [Indexed: 12/17/2022]
Abstract
The advent of next generation sequencing has revolutionized research approaches to biology by making entire genome sequences available and marking a new age in biology that has the potential to open innovative research avenues in various fields. Genome sequencing is now being applied in the fields of forest ecology and forest pathology, which previously had limited access to molecular techniques. One of the most advanced areas of progress is the study of "pine wilt disease", which is caused by the parasitic nematode, Bursaphelenchus xylophilus. The entire genome sequence of B. xylophilus was determined in 2011, and since then, proteomic studies have been conducted to understand the molecular basis of the parasitism and pathogenicity of B. xylophilus. These postgenomic studies have provided numerous molecular insights and greatly changed our understanding of the pathogenesis of pine wilt disease. Here, we review the recent advances in genomic and proteomic approaches that address some of the longstanding questions behind the pathogenesis of pine wilt disease and have identified future questions and directions in this regard.
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Affiliation(s)
- Ryoji Shinya
- Howard Hughes Medical Institute and Division of Biology, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA.
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17
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Yan X, Cheng XY, Wang YS, Luo J, Mao ZC, Ferris VR, Xie BY. Comparative transcriptomics of two pathogenic pinewood nematodes yields insights into parasitic adaptation to life on pine hosts. Gene 2012; 505:81-90. [PMID: 22705985 DOI: 10.1016/j.gene.2012.05.041] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 04/03/2012] [Accepted: 05/18/2012] [Indexed: 02/07/2023]
Abstract
Bursaphelenchus xylophilus and Bursaphelenchus mucronatus are migratory endoparasitic nematodes that live in pine trees. To gain insight into their molecular similarities and differences, transcriptomes of the two nematodes were analysed. A total of 23,765 and 21,782 contigs (>300 bp) were obtained from B. xylophilus and B. mucronatus, respectively. More than 80% of the contigs could map to each other's transcriptome reciprocally. A total of 23,467 and 21,370 Open Reading Frames were predicted, respectively. Besides those known parasitism-related proteins, six new venom allergen-like proteins (VAPs) were found, which were not homologous to known VAPs. Enzymes involved in xenobiotic biodegradation were abundant in the two transcriptomes based on KEGG functional annotation. Metabolism of xenobiotics by cytochrome P450 comprised the main detoxification pathways. The mRNA expression levels of detoxification genes in nematodes living in the host were higher than those in nematodes feeding on fungus. However, there were fewer enzymes involved in the α-pinene degradation. Our results indicate that the two pinewood nematodes have evolved similar molecular mechanisms to adapt to life on pine hosts.
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Affiliation(s)
- Xia Yan
- College of Life Sciences, Beijing Normal University, Beijing, China
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18
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Kang JS, Koh YH, Moon YS, Lee SH. Molecular properties of a venom allergen-like protein suggest a parasitic function in the pinewood nematode Bursaphelenchus xylophilus. Int J Parasitol 2011; 42:63-70. [PMID: 22142561 DOI: 10.1016/j.ijpara.2011.10.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 10/26/2011] [Accepted: 10/27/2011] [Indexed: 11/25/2022]
Abstract
The pinewood nematode, Bursaphelenchus xylophilus, is a destructive pest in several countries including Japan, China and Korea. Of three genes encoding the venom allergen-like protein in B. xylophilus, Bxvap-1 showed the highest transcript levels at the pine-grown propagative stage. In addition, western blot and immunohistochemical analyses using anti-BxVap-1 polyclonal antibody verified a specific increase in BxVap-1 expression levels at the pine-grown propagative stage. Using immunohistochemistry, BxVap-1 was detected around the putative oesophageal glands and metacarpus, suggesting that BxVap-1 is secreted into the host pine tree and is involved in the parasitic mechanism. To explain the parasitic role of BxVap-1, we measured the migration rate inside pine seedlings of B. xylophilus either with or without Bxvap-1 knockdown by RNA interference. Bxvap-1 knockdown resulted in a significantly lower migration rate in the >6cm region compared with the control B. xylophilus. These results suggest that BxVap-1 is involved in B. xylophilus migration, perhaps by suppressing the pine tree defence mechanism.
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Affiliation(s)
- Jae Soon Kang
- Research Institute for Agriculture and Life Science, Seoul National University, 151-921 Seoul, Republic of Korea
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19
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Kikuchi T, Cotton JA, Dalzell JJ, Hasegawa K, Kanzaki N, McVeigh P, Takanashi T, Tsai IJ, Assefa SA, Cock PJA, Otto TD, Hunt M, Reid AJ, Sanchez-Flores A, Tsuchihara K, Yokoi T, Larsson MC, Miwa J, Maule AG, Sahashi N, Jones JT, Berriman M. Genomic insights into the origin of parasitism in the emerging plant pathogen Bursaphelenchus xylophilus. PLoS Pathog 2011; 7:e1002219. [PMID: 21909270 PMCID: PMC3164644 DOI: 10.1371/journal.ppat.1002219] [Citation(s) in RCA: 271] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 06/28/2011] [Indexed: 01/17/2023] Open
Abstract
Bursaphelenchus xylophilus is the nematode responsible for a devastating epidemic of pine wilt disease in Asia and Europe, and represents a recent, independent origin of plant parasitism in nematodes, ecologically and taxonomically distinct from other nematodes for which genomic data is available. As well as being an important pathogen, the B. xylophilus genome thus provides a unique opportunity to study the evolution and mechanism of plant parasitism. Here, we present a high-quality draft genome sequence from an inbred line of B. xylophilus, and use this to investigate the biological basis of its complex ecology which combines fungal feeding, plant parasitic and insect-associated stages. We focus particularly on putative parasitism genes as well as those linked to other key biological processes and demonstrate that B. xylophilus is well endowed with RNA interference effectors, peptidergic neurotransmitters (including the first description of ins genes in a parasite) stress response and developmental genes and has a contracted set of chemosensory receptors. B. xylophilus has the largest number of digestive proteases known for any nematode and displays expanded families of lysosome pathway genes, ABC transporters and cytochrome P450 pathway genes. This expansion in digestive and detoxification proteins may reflect the unusual diversity in foods it exploits and environments it encounters during its life cycle. In addition, B. xylophilus possesses a unique complement of plant cell wall modifying proteins acquired by horizontal gene transfer, underscoring the impact of this process on the evolution of plant parasitism by nematodes. Together with the lack of proteins homologous to effectors from other plant parasitic nematodes, this confirms the distinctive molecular basis of plant parasitism in the Bursaphelenchus lineage. The genome sequence of B. xylophilus adds to the diversity of genomic data for nematodes, and will be an important resource in understanding the biology of this unusual parasite.
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Affiliation(s)
- Taisei Kikuchi
- Forestry and Forest Products Research Institute, Tsukuba, Japan.
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