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Shobade SO, Zabotina OA, Nilsen-Hamilton M. Plant root associated chitinases: structures and functions. FRONTIERS IN PLANT SCIENCE 2024; 15:1344142. [PMID: 38362446 PMCID: PMC10867124 DOI: 10.3389/fpls.2024.1344142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Accepted: 01/05/2024] [Indexed: 02/17/2024]
Abstract
Chitinases degrade chitin, a linear homopolymer of β-1,4-linked N-acetyl-D-glucosamine (GlcNAc) residues found in the cell walls of fungi and the exoskeletons of arthropods. They are secreted by the roots into the rhizosphere, a complex and dynamic environment where intense nutrient exchange occurs between plants and microbes. Here we modeled, expressed, purified, and characterized Zea mays and Oryza sativa root chitinases, and the chitinase of a symbiotic bacterium, Chitinophaga oryzae 1303 for their activities with chitin, di-, tri-, and tetra-saccharides and Aspergillus niger, with the goal of determining their role(s) in the rhizosphere and better understanding the molecular mechanisms underlying plant-microbe interactions. We show that Zea mays basic endochitinase (ZmChi19A) and Oryza sativa chitinase (OsChi19A) are from the GH19 chitinase family. The Chitinophaga oryzae 1303 chitinase (CspCh18A) belongs to the GH18 family. The three enzymes have similar apparent K M values of (20-40 µM) for the substrate 4-MU-GlcNAc3. They vary in their pH and temperature optima with OsChi19A activity optimal between pH 5-7 and 30-40°C while ZmChi19A and CspCh18A activities were optimal at pH 7-9 and 50-60°C. Modeling and site-directed mutation of ZmChi19A identified the catalytic cleft and the active residues E147 and E169 strategically positioned at ~8.6Å from each other in the folded protein. Cleavage of 4-MU-GlcNAc3 was unaffected by the absence of the CBD but diminished in the absence of the flexible C-terminal domain. However, unlike for the soluble substrate, the CBD and the newly identified flexible C-terminal domain were vital for inhibiting Aspergillus niger growth. The results are consistent with the involvement of the plant chitinases in defense against pathogens like fungi that have chitin exoskeletons. In summary, we have characterized the functional features and structural domains necessary for the activity of two plant root chitinases that are believed to be involved in plant defense and a bacterial chitinase that, along with the plant chitinases, may participate in nutrient recycling in the rhizosphere.
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Affiliation(s)
- Samuel O. Shobade
- Ames National Laboratory, U. S. Department of Energy, Ames, IA, United States
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States
| | - Olga A. Zabotina
- Ames National Laboratory, U. S. Department of Energy, Ames, IA, United States
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States
| | - Marit Nilsen-Hamilton
- Ames National Laboratory, U. S. Department of Energy, Ames, IA, United States
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States
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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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Shen S, Ding B, Jiang X, Yang M, Yang Q, Dong L. Discovery of novel inhibitors targeting nematode chitinase C eCht1: Virtual screening, biological evaluation, and molecular dynamics simulation. Front Chem 2022; 10:1021295. [PMID: 36405330 PMCID: PMC9669442 DOI: 10.3389/fchem.2022.1021295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 10/18/2022] [Indexed: 04/19/2024] Open
Abstract
Plant-parasitic nematodes are a main limiting factor for worldwide agriculture. To reduce the global burden of nematode infections, chemical nematicides are still the most effective methods to manage nematodes. With the increasing resistance of nematodes, the development of new anti-nematicides drug is urgent. Nematode chitinases are found to play important roles in various physiological functions, such as larva moulting, hatching from eggshell, and host infection. Inhibition of nematode chitinase is considered a promising strategy for the development of eco-friendly nematicides. In this study, to develop novel nematode chitinase CeCht1 inhibitors, virtual screening of the ZINC database was performed using the pesticide-likeness rules, pharmacophore-based and docking-based approach in turn. Compounds HAU-4 and HAU-7 were identified as potent CeCht1 inhibitors with the IC50 values of 4.2 μM and 10.0 μM, respectively. Moreover, molecular dynamics simulations combined with binding free energy and free energy decomposition calculations were conducted to investigate the basis for the potency of the two inhibitors toward CeCht1. This work gives an insight into the future rational development of novel and potent nematode chitinase inhibitors.
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Affiliation(s)
- Shengqiang Shen
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Baokang Ding
- State Key Laboratory of North China Crop Improvement and Regulation, College of Plant Protection, Hebei Agricultural University, Baoding, China
| | - Xi Jiang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Guangdong Laboratory for Lingnan Modern Agriculture (Shenzhen Branch), Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Meiling Yang
- State Key Laboratory of North China Crop Improvement and Regulation, College of Plant Protection, Hebei Agricultural University, Baoding, China
| | - Qing Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Guangdong Laboratory for Lingnan Modern Agriculture (Shenzhen Branch), Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Lili Dong
- State Key Laboratory of North China Crop Improvement and Regulation, College of Plant Protection, Hebei Agricultural University, Baoding, China
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Gama MDVF, Moraes CS, Gomes B, Diaz-Albiter HM, Mesquita RD, Seabra-Junior E, Azambuja P, Garcia EDS, Genta FA. Structure and expression of Rhodnius prolixus GH18 chitinases and chitinase-like proteins: Characterization of the physiological role of RpCht7, a gene from subgroup VIII, in vector fitness and reproduction. Front Physiol 2022; 13:861620. [PMID: 36262251 PMCID: PMC9574080 DOI: 10.3389/fphys.2022.861620] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 08/12/2022] [Indexed: 11/22/2022] Open
Abstract
Chitinases are enzymes responsible for the hydrolysis of glycosidic linkages within chitin chains. In insects, chitinases are typically members of the multigenic glycoside hydrolase family 18 (GH18). They participate in the relocation of chitin during development and molt, and in digestion in detritivores and predatory insects, and they control the peritrophic membrane thickness. Chitin metabolism is a promising target for developing vector control strategies, and knowledge of the roles of chitinases may reveal new targets and illuminate unique aspects of their physiology and interaction with microorganisms. Rhodnius prolixus is an important vector of Chagas disease, which is caused by the parasite Trypanosoma cruzi. In this study, we performed annotation and structural characterization of nine chitinase and chitinase-like protein genes in the R. prolixus genome. The roles of their corresponding transcripts were studied in more depth; their physiological roles were studied through RNAi silencing. Phylogenetic analysis of coding sequences showed that these genes belong to different subfamilies of GH18 chitinases already described in other insects. The expression patterns of these genes in different tissues and developmental stages were initially characterized using RT-PCR. RNAi screening showed silencing of the gene family members with very different efficiencies. Based on the knockdown results and the general lack of information about subgroup VIII of GH18, the RpCht7 gene was chosen for phenotype analysis. RpCht7 knockdown doubled the mortality in starving fifth-instar nymphs compared to dsGFP-injected controls. However, it did not alter blood intake, diuresis, digestion, molting rate, molting defects, sexual ratio, percentage of hatching, or average hatching time. Nevertheless, female oviposition was reduced by 53% in RpCht7-silenced insects, and differences in oviposition occurred within 14–20 days after a saturating blood meal. These results suggest that RpCht7 may be involved in the reproductive physiology and vector fitness of R. prolixus.
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Affiliation(s)
| | | | - Bruno Gomes
- Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - Hector Manuel Diaz-Albiter
- Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
- El Colegio de la Frontera Sur, ECOSUR, Campeche, Mexico
| | - Rafael Dias Mesquita
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Eloy Seabra-Junior
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Patrícia Azambuja
- Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, Brazil
- Universidade Federal Fluminense, UFF, Rio de Janeiro, Brazil
| | - Eloi de Souza Garcia
- Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, Brazil
| | - Fernando Ariel Genta
- Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, Brazil
- *Correspondence: Fernando Ariel Genta, ,
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Gong S, Meng Q, Qiao J, Huang Y, Zhong W, Zhang G, Zhang K, Li N, Shang Y, Li Z, Cai X. Biological Characteristics of Recombinant Arthrobotrys oligospora Chitinase AO-801. THE KOREAN JOURNAL OF PARASITOLOGY 2022; 60:345-352. [PMID: 36320111 PMCID: PMC9633153 DOI: 10.3347/kjp.2022.60.5.345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 09/15/2022] [Accepted: 09/15/2022] [Indexed: 11/24/2023]
Abstract
Chitinase AO-801 is a hydrolase secreted by Arthrobotrys oligospora during nematode feeding, while its role remained elusive. This study analyzed the molecular characteristics of recombinant chitinase of Arthrobotrys oligospora (reAO-801). AO-801 belongs to the typical glycoside hydrolase 18 family with conserved chitinase sequence and tertiary structure of (α/β)8 triose-phosphate isomerase (TIM) barrel. The molecular weight of reAO-801 was 42 kDa. reAO-801 effectively degraded colloidal and powdered chitin, egg lysate, and stage I larval lysate of Caenorhabditis elegans. The activity of reAO-801 reached its peak at 40˚C and pH values between 4-7. Enzyme activity was inhibited by Zn2+, Ca2+, and Fe3+, whereas Mg2+ and K+ potentiated its activity. In addition, urea, sodium dodecyl sulfate, and 2-mercaptoethanol significantly inhibited enzyme activity. reAO-801 showed complete nematicidal activity against C. elegans stage I larvae. reAO-801 broke down the C. elegans egg shells, causing them to die or die prematurely by hatching the eggs. It also invoked degradation of Haemonchus contortus eggs, resulting in apparent changes in the morphological structure. This study demonstrated the cytotoxic effect of reAO-801, which laid the foundation for further dissecting the mechanism of nematode infestation by A. oligospora.
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Affiliation(s)
- Shasha Gong
- College of Animal Science & Technology, Shihezi University, Shihezi, Xinjiang 832003,
China
| | - Qingling Meng
- College of Animal Science & Technology, Shihezi University, Shihezi, Xinjiang 832003,
China
| | - Jun Qiao
- College of Animal Science & Technology, Shihezi University, Shihezi, Xinjiang 832003,
China
| | - Yunfu Huang
- College of Animal Science & Technology, Shihezi University, Shihezi, Xinjiang 832003,
China
| | - Wenqiang Zhong
- College of Animal Science & Technology, Shihezi University, Shihezi, Xinjiang 832003,
China
| | - Guowu Zhang
- College of Animal Science & Technology, Shihezi University, Shihezi, Xinjiang 832003,
China
| | - Kai Zhang
- College of Animal Science & Technology, Shihezi University, Shihezi, Xinjiang 832003,
China
| | - Ningxing Li
- College of Animal Science & Technology, Shihezi University, Shihezi, Xinjiang 832003,
China
| | - Yunxia Shang
- College of Animal Science & Technology, Shihezi University, Shihezi, Xinjiang 832003,
China
| | - Zhiyuan Li
- College of Animal Science & Technology, Shihezi University, Shihezi, Xinjiang 832003,
China
| | - Xuepeng Cai
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu 730046,
China
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6
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Chen W, Chen Q, Kumar A, Jiang X, Zhang KYJ, Yang Q. Structure-based virtual screening of highly potent inhibitors of the nematode chitinase CeCht1. J Enzyme Inhib Med Chem 2021; 36:1198-1204. [PMID: 34074203 PMCID: PMC8174485 DOI: 10.1080/14756366.2021.1931862] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Nematode chitinases play vital roles in various physiological processes, including egg hatching, larva moulting, and reproduction. Small-molecule inhibitors of nematode chitinases have potential applications for controlling nematode pests. On the basis of the crystal structure of CeCht1, a representative chitinase indispensable to the eggshell chitin degradation of the model nematode Caenorhabditis elegans, we have discovered a series of novel inhibitors bearing a (R)-3,4-diphenyl-4,5-dihydropyrrolo[3,4-c]pyrazol-6(2H)-one scaffold by hierarchical virtual screening. The crystal structures of CeCht1 complexed with two of these inhibitors clearly elucidated their interactions with the enzyme active site. Based on the inhibitory mechanism, several analogues with improved inhibitory activities were identified, among which the compound PP28 exhibited the most potent activity with a Ki value of 0.18 μM. This work provides the structural basis for the development of novel nematode chitinase inhibitors.
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Affiliation(s)
- Wei Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qi Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ashutosh Kumar
- Laboratory for Structural Bioinformatics, Center for Biosystems Dynamics Research, RIKEN, Yokohama, Japan
| | - Xi Jiang
- Guangdong Laboratory for Lingnan Modern Agriculture (Shenzhen Branch), Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Kam Y J Zhang
- Laboratory for Structural Bioinformatics, Center for Biosystems Dynamics Research, RIKEN, Yokohama, Japan
| | - Qing Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.,Guangdong Laboratory for Lingnan Modern Agriculture (Shenzhen Branch), Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.,School of Bioengineering, Dalian University of Technology, Dalian, China
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7
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Chen Q, Chen W, Kumar A, Jiang X, Janezic M, Zhang KYJ, Yang Q. Crystal Structure and Structure-Based Discovery of Inhibitors of the Nematode Chitinase CeCht1. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:3519-3526. [PMID: 33691404 DOI: 10.1021/acs.jafc.1c00162] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Nematode chitinases play crucial roles in various processes of the nematode lifecycle, including hatching, molting, and reproduction. Small-molecule inhibitors of nematode chitinases have shown promise for controlling nematode pests. However, the lack of structural information makes it a challenge to develop nematicides targeting nematode chitinases. Here, we report the first crystal structure of a representative nematode chitinase, that of CeCht1 from the model nematode Caenorhabditis elegans, to a 1.7 Å resolution. CeCht1 is a highly conserved chitinase among nematodes, and structural comparison with other chitinases revealed that CeCht1 has a classical TIM-barrel fold with some subtle structural differences in the substrate-binding cleft. Benefiting from the obtained crystal structure, we identified a series of novel inhibitors by hierarchical virtual screening. Analysis of the structure-activity relationships of these compounds provided insight into their interactions with the enzyme active site, which may inform future work in improving the potencies of their inhibitory activities. This work gives an insight into the structural features of nematode chitinases and provides a solid basis for the development of inhibitors.
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Affiliation(s)
- Qi Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Wei Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Ashutosh Kumar
- Laboratory for Structural Bioinformatics, Center for Biosystems Dynamics Research, RIKEN, Yokohama, Kanagawa 230-0045, Japan
| | - Xi Jiang
- Guangdong Laboratory for Lingnan Modern Agriculture (Shenzhen Branch), Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China
| | - Matej Janezic
- Laboratory for Structural Bioinformatics, Center for Biosystems Dynamics Research, RIKEN, Yokohama, Kanagawa 230-0045, Japan
| | - Kam Y J Zhang
- Laboratory for Structural Bioinformatics, Center for Biosystems Dynamics Research, RIKEN, Yokohama, Kanagawa 230-0045, Japan
| | - Qing Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Guangdong Laboratory for Lingnan Modern Agriculture (Shenzhen Branch), Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China
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Feng H, Zhou D, Daly P, Wang X, Wei L. Characterization and Functional Importance of Two Glycoside Hydrolase Family 16 Genes from the Rice White Tip Nematode Aphelenchoides besseyi. Animals (Basel) 2021; 11:ani11020374. [PMID: 33540794 PMCID: PMC7913077 DOI: 10.3390/ani11020374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/26/2021] [Accepted: 01/31/2021] [Indexed: 01/02/2023] Open
Abstract
Simple Summary The rice white tip nematode Aphelenchoides besseyi is a plant parasite but can also feed on fungi if this alternative nutrient source is available. Glucans are a major nutrient source found in fungi, and β-linked glucans from fungi can be hydrolyzed by β-glucanases from the glycoside hydrolase family 16 (GH16). The GH16 family is abundant in A. besseyi, but their functions have not been well studied, prompting the analysis of two GH16 members (AbGH16-1 and AbGH16-2). AbGH16-1 and AbGH16-2 are most similar to GH16s from fungi and probably originated from fungi via a horizontal gene transfer event. These two genes are important for feeding on fungi: transcript levels increased when cultured with the fungus Botrytis cinerea, and the purified AbGH16-1 and AbGH16-2 proteins inhibited the growth of B. cinerea. When AbGH16-1 and AbGH16-2 expression was silenced, the reproduction ability of A. besseyi was reduced. These findings have proved for the first time that GH16s contribute to the feeding and reproduction of A. besseyi, which thus provides novel insights into how plant-parasitic nematodes can obtain nutrition from sources other than their plant hosts. Abstract The glycoside hydrolase family 16 (GH16) is widely found in prokaryotes and eukaryotes, and hydrolyzes the β-1,3(4)-linkages in polysaccharides. Notably, the rice white tip nematode Aphelenchoides besseyi harbors a higher number of GH16s compared with other plant-parasitic nematodes. In this work, two GH16 genes, namely AbGH16-1 and AbGH16-2, were isolated and characterized from A. besseyi. The deduced amino acid sequences of AbGH16-1 and AbGH16-2 contained an N-terminal signal peptide and a fungal Lam16A glucanase domain. Phylogenetic analysis revealed that AbGH16-1 and AbGH16-2 clustered with ascomycete GH16s, suggesting AbGH16-1 and AbGH16-2 were acquired by horizontal gene transfer from fungi. In situ hybridization showed that both AbGH16-1 and AbGH16-2 were specifically expressed in the nematode gonads, correlating with qPCR analysis that showed the high transcript levels of the two genes in the female nematodes. AbGH16-1 and AbGH16-2 were also significantly induced in nematodes feeding on Botrytis cinerea. Characterization of the recombinant protein showed AbGH16-1 and AbGH16-2 displayed pronounced inhibition of both conidial germination and germ tube elongation of B. cinerea. In addition, silencing of AbGH16-1 and AbGH16-2 by RNA interference significantly decreased the reproduction ability of A. besseyi and had a profound impact on the development process of offspring in this nematode. These findings have firstly proved that GH16s may play important roles in A.besseyi feeding and reproduction on fungi, which thus provides novel insights into the function of GH16s in plant-parasitic nematodes.
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Glycoside hydrolase family 18 chitinases: The known and the unknown. Biotechnol Adv 2020; 43:107553. [DOI: 10.1016/j.biotechadv.2020.107553] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/09/2020] [Accepted: 04/20/2020] [Indexed: 12/13/2022]
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10
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Liu HB, Rui L, Feng YQ, Wu XQ. Autophagy contributes to resistance to the oxidative stress induced by pine reactive oxygen species metabolism, promoting infection by Bursaphelenchus xylophilus. PEST MANAGEMENT SCIENCE 2020; 76:2755-2767. [PMID: 32187440 DOI: 10.1002/ps.5823] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 02/25/2020] [Accepted: 03/18/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND Autophagy plays an important role in eukaryotes. We investigated its role in the pine wood nematode (PWN), Bursaphelenchus xylophilus, the causative agent of pine wilt disease (PWD), to find promising control strategies against PWD. RESULTS We analysed the expression levels of PtRBOH1 and PtRBOH2, which regulate reactive oxygen species (ROS) metabolism, in Pinus thunbergii and the expression of three autophagy genes, BxATG5, BxATG9 and BxATG16, in PWN by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and measured the content of H2 O2 , the main product of ROS metabolism, in pine stem. There was a correlation between the expression of autophagy genes in PWN and pine ROS metabolism during early infection. We also found that oxidative stress induces autophagy in PWN according to qRT-PCR, transmission electron microscopy and Western blot analyses. Inhibition of autophagy by 3-methyladenine or silencing of the autophagy genes BxATG9 and BxATG16 in PWN showed that autophagy is essential for feeding, fecundity, egg hatching and survival of PWN under oxidative stress, confirming the importance of autophagy in the antioxidant defences of PWN. Similarly, we demonstrated that autophagy contributes to the virulence of PWN. Moreover, PWN likely ameliorates oxidative damage by enhancing the activities of the peroxidase and catalase antioxidant pathways when autophagy is inhibited. CONCLUSION Autophagy contributes to resistance to the oxidative stress induced by pine ROS metabolism, thus promoting infection by PWN. Our findings clarify the defence mechanisms of PWN and the pathogenesis of PWD, and provide promising hints for control of PWD by blocking autophagy. © 2020 Society of Chemical Industry.
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Affiliation(s)
- Hong-Bin Liu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, China
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing Forestry University, Nanjing, China
| | - Lin Rui
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, China
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing Forestry University, Nanjing, China
| | - Ya-Qi Feng
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, China
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing Forestry University, Nanjing, China
| | - Xiao-Qin Wu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, China
- Jiangsu Key Laboratory for Prevention and Management of Invasive Species, Nanjing Forestry University, Nanjing, China
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Tanaka SE, Dayi M, Maeda Y, Tsai IJ, Tanaka R, Bligh M, Takeuchi-Kaneko Y, Fukuda K, Kanzaki N, Kikuchi T. Stage-specific transcriptome of Bursaphelenchus xylophilus reveals temporal regulation of effector genes and roles of the dauer-like stages in the lifecycle. Sci Rep 2019; 9:6080. [PMID: 30988401 PMCID: PMC6465311 DOI: 10.1038/s41598-019-42570-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 04/01/2019] [Indexed: 12/24/2022] Open
Abstract
The pine wood nematode Bursaphelenchus xylophilus is the causal agent of pine wilt disease, one of the most devastating forest diseases in East Asian and West European countries. The lifecycle of B. xylophilus includes four propagative larval stages and gonochoristic adults which are involved in the pathogenicity, and two stages of dispersal larvae involved in the spread of the disease. To elucidate the ecological roles of each developmental stage in the pathogenic life cycle, we performed a comprehensive transcriptome analysis using RNA-seq generated from all developmental stages of B. xylophilus and compared transcriptomes between stages. We found more than 9000 genes are differentially expressed in at least one stage of the life cycle including genes involved in general nematode biology such as reproduction and moulting but also effector genes likely to be involved in parasitism. The dispersal-stage transcriptome revealed its analogy to C. elegans dauer and the distinct roles of the two larval stages from each other regarding survival and transmission. This study provides important insights and resources to understand B. xylophilus parasitic biology.
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Affiliation(s)
- Suguru E Tanaka
- Laboratory of Forest Botany, Graduate School of Agricultural and Life Sciences, the University of Tokyo, Tokyo, 113-8657, Japan
| | - Mehmet Dayi
- Division of Parasitology, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan
- Forestry Vocational School, Duzce University, 81620, Duzce, Turkey
| | - Yasunobu Maeda
- Division of Parasitology, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan
| | - Isheng J Tsai
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Ryusei Tanaka
- Division of Parasitology, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan
| | - Mark Bligh
- Division of Parasitology, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan
| | - Yuko Takeuchi-Kaneko
- Laboratory of Terrestrial Microbial Ecology, Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
| | - Kenji Fukuda
- Laboratory of Forest Botany, Graduate School of Agricultural and Life Sciences, the University of Tokyo, Tokyo, 113-8657, Japan
| | - Natsumi Kanzaki
- Kansai Research Center, Forestry and Forest Products Research Institute, Kyoto, 612-0855, Japan
| | - Taisei Kikuchi
- Division of Parasitology, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan.
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Chen Q, Peng D. Nematode Chitin and Application. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1142:209-219. [PMID: 31102248 DOI: 10.1007/978-981-13-7318-3_10] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Plant-parasitic nematode infection is a global problem for agriculture and forestry. There is clearly a need for novel nematicides, because of the pitifully small repertoire of nematicides available and the effectiveness of losing or environmental prohibition of these nematicides. Chitin is the essential component of nematode eggshell and pharynx. The disturbance of chitin synthesis or hydrolysis led to nematode embryonic lethal, laying defective eggs or moulting failure. Thus, the key components in the chitin metabolic process are promising targets for anti-nematode agent's development. In this chapter, we focus on chitin and chitin synthase of nematodes, chitinases and their roles in nematode survival and application of chitin in nematode control.
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Affiliation(s)
- Qi Chen
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Deliang Peng
- Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
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