RNAi of esophageal gland-specific gene Mi-msp-1 alters early stage infection behaviour of root-knot nematode, Meloidogyne incognita

Identifying parasitism genes encoding proteins secreted from a nematode's esophageal gland cells and injected through its stylet into plant tissue is the key to understanding the molecular basis of nematode parasitism of plants. Meloidogyne incognita parasitism genes were cloned by microaspirating the cytoplasm from the esophageal gland cells of different parasitic stages to provide mRNA to create a gland cell-specific cDNA library by long-distance reverse-transcriptase polymerase chain reaction. Of 2,452 cDNA clones sequenced, deduced protein sequences of 185 cDNAs had a signal peptide for secretion and, thus, could have a role in root-knot nematode parasitism of plants. High-throughput in situ hybridization with cDNA clones encoding signal peptides resulted in probes of 37 unique clones specifically hybridizing to transcripts accumulating within the subventral (13 clones) or dorsal (24 clones) esophageal gland cells of M. incognita. In BLASTP analyses, 73% of the predicted proteins were novel proteins. Those with similarities to known proteins included a pectate lyase, acid phosphatase, and hypothetical proteins from other organisms. Our cell-specific analysis of genes encoding secretory proteins provided, for the first time, a profile of putative parasitism genes expressed in the M. incognita esophageal gland cells throughout the parasitic cycle.

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A Set of Genes Differentially Expressed Between Avirulent and Virulent Meloidogyne incognita Near-Isogenic Lines Encode Secreted Proteins

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2003.16.12.1077 ◽

2003 ◽

Vol 16 (12) ◽

pp. 1077-1084 ◽

Cited By ~ 31

Author(s):

Cédric Neveu ◽

Stéphanie Jaubert ◽

Pierre Abad ◽

Philippe Castagnone-Sereno

Keyword(s):

Meloidogyne Incognita ◽

Expression Profiles ◽

Gene Expression Profiles ◽

Differentially Expressed ◽

Near Isogenic Lines ◽

Root Knot Nematode ◽

Significant Similarity ◽

Cdna Sequences ◽

Isogenic Lines ◽

Esophageal Gland

A cDNA-amplification fragment length polymorphism (AFLP)-based strategy has been used to identify genes differentially expressed between two pairs of near-isogenic lines (NIL) of the root-knot nematode Meloidogyne incognita either avirulent or virulent against the tomato Mi resistance gene. Gene expression profiles from infective second-stage juveniles (J2) were compared, and 22 of the 24,025 transcript-derived fragments (TDF) generated proved to be differential, i.e., present in both avirulent NIL and absent in both virulent NIL. Fourteen of the TDF sequences did not show any significant similarity to known proteins, while eight matched reported sequences from nematodes and other invertebrates. The differential expression of nine genes was confirmed by reverse transcription-polymerase chain reaction (RT-PCR) experiments. In situ hybridization conducted with five of the sequences showed that two were specifically expressed in the intestinal cells (HM10 and PM1), one in the subventral esophageal glands (HM1), and two in the dorsal esophageal gland of J2 (HM7 and HM12). Analysis of full-length cDNA sequences revealed the presence of a signal peptide for HM1, HM10, and HM12, indicating that the encoded proteins are putatively secreted. Since secreted products in general and esophageal gland secretions in particular are thought to be among the main M. incognita pathogenicity factors, this result suggests a possible dual role for some of the genes encoding such secretions, i.e., they could be involved in both pathogenicity and virulence or avirulence of these biotrophic parasites.

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Transcriptomic and Histological Analysis of the Response of Susceptible and Resistant Cucumber to Meloidogyne incognita Infection Revealing Complex Resistance via Multiple Signaling Pathways

Frontiers in Plant Science ◽

10.3389/fpls.2021.675429 ◽

2021 ◽

Vol 12 ◽

Author(s):

Xvzhen Li ◽

Yinhui Sun ◽

Yuting Yang ◽

Xiaopei Yang ◽

Wanyu Xue ◽

...

Keyword(s):

Signaling Pathways ◽

Signaling Pathway ◽

Meloidogyne Incognita ◽

Host Resistance ◽

Calcium Binding ◽

Molecular Mechanisms ◽

Early Stage ◽

Resistance Mechanism ◽

Continuous Cropping ◽

Root Knot Nematode

The root-knot nematode (RKN), Meloidogyne incognita, is a devastating pathogen for cucumber (Cucumis sativus L.) specially in production under protected environments or continuous cropping. High level RKN resistance has been identified in African horned melon Cucumis metuliferus (CM). However, the resistance mechanism remains unclear. In this study, the comparative analysis on phenotypic and transcriptomic responses in the susceptible cucumber inbred line Q24 and the resistant CM, after M. incognita infection, was performed. The results showed that, in comparison with Q24, the CM was able to significantly reduce penetration numbers of second stage juveniles (J2), slow its development in the roots resulting in fewer galls and smaller giant cells suggesting the presence of host resistance in CM. Comparative transcriptomes analysis of Q24 and CM before and after M. incognita infection was conducted and differentially expressed genes (DEGs) associated with host resistance were identified in CM. Enrichment analyses revealed most enriched DEGs in Ca2+ signaling, salicylic acid (SA)/jamonate signaling (JA), as well as auxin (IAA) signaling pathways. In particular, in CM, DEGs in the Ca2+ signaling pathway such as those for the calmodulin and calcium-binding proteins were upregulated at the early stage of M. incognita infection; genes for SA/JA synthesis/signal transduction were markedly activated, whereas the IAA signaling pathway genes were inhibited upon infection suggesting the importance of SA/JA signaling pathways in mediating M. incognita resistance in CM. A model was established to explain the different molecular mechanisms on M. incognita susceptibility in cucumber and resistance to M. incognita infection in CM.

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Resistance mechanisms ofPrunusrootstocks to root-knot nematode,Meloidogyne incognita

Fruits ◽

10.1051/fruits/2009024 ◽

2009 ◽

Vol 64 (5) ◽

pp. 295-303 ◽

Cited By ~ 1

Author(s):

Hang Ye ◽

Wen-jun Wang ◽

Guo-jie Liu ◽

Li-xin Zhu ◽

Ke-gong Jia

Keyword(s):

Meloidogyne Incognita ◽

Resistance Mechanisms ◽

Root Knot Nematode

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Intestinal pathologic findings at early stage infection by Centrocestus armatus in albino rats

The Korean Journal of Parasitology ◽

10.3347/kjp.1997.35.2.135 ◽

1997 ◽

Vol 35 (2) ◽

pp. 135 ◽

Cited By ~ 9

Author(s):

S J Hong ◽

J H Han ◽

C K Park ◽

S Y Kang

Keyword(s):

Early Stage ◽

Albino Rats ◽

Pathologic Findings ◽

Stage Infection

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dl-β-Amino butyric acid induced resistance in tomato against root-knot nematode Meloidogyne incognita under salt stress condition

Indian Phytopathology ◽

10.1007/s42360-021-00320-8 ◽

2021 ◽

Author(s):

Mohd Asif ◽

Faryad Khan ◽

Taruba Ansari ◽

Faheem Ahmad ◽

Moh Tariq ◽

...

Keyword(s):

Salt Stress ◽

Induced Resistance ◽

Butyric Acid ◽

Meloidogyne Incognita ◽

Stress Condition ◽

Root Knot Nematode ◽

Salt Stress Condition ◽

Amino Butyric Acid

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Genetic Diversity, Virulence, and Meloidogyne incognita Interactions of Fusarium oxysporum Isolates Causing Cotton Wilt in Georgia

Plant Disease ◽

10.1094/pdis-09-16-1382-re ◽

2017 ◽

Vol 101 (6) ◽

pp. 948-956 ◽

Cited By ~ 9

Author(s):

Alois A. Bell ◽

Robert C. Kemerait ◽

Carlos S. Ortiz ◽

Sandria Prom ◽

Jose Quintana ◽

...

Keyword(s):

Genetic Diversity ◽

Fusarium Oxysporum ◽

Meloidogyne Incognita ◽

Root Knot Nematode ◽

Soil Infestation ◽

Causal Pathogen ◽

Complementation Groups ◽

Shoot Weight ◽

Cotton Wilt ◽

Significant Disease

Locally severe outbreaks of Fusarium wilt of cotton (Gossypium spp.) in South Georgia raised concerns about the genotypes of the causal pathogen, Fusarium oxysporum f. sp. vasinfectum. Vegetative complementation tests and DNA sequence analysis were used to determine genetic diversity among 492 F. oxysporum f. sp. vasinfectum isolates obtained from 107 wilted plants collected from seven fields in five counties. Eight vegetative complementation groups (VCG) were found, with VCG 01117B and VCG 01121 occurring in 66% of the infected plants. The newly recognized VCG 01121 was the major VCG in Berrien County, the center of the outbreaks. All eight VCG resulted in significant increases in the percentages of wilted leaves (27 to 53%) and significant reductions in leaf weight (40 to 67%) and shoot weight (33 to 60%) after being stem punctured into Gossypium hirsutum ‘Rowden’. They caused little or no significant reductions in shoot weight and height or increases in foliar symptoms and vascular browning in a soil-infestation assay. Soil infestation with Meloidogyne incognita race 3 (root-knot nematode) alone also failed to cause significant disease. When coinoculated with M. incognita race 3, all VCG caused moderate to severe wilt. Therefore, the VCG identified in this study belong to the vascular-competent pathotype, and should pose similar threats to cotton cultivars in the presence of the root-knot nematode. Use of nematode-resistant cultivars, therefore, is probably the best approach to control the disease in Georgia.

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The role of Caenorhabditis elegans sex-determination homologs, Mi-sdc-1 and Mi-tra-1 in Meloidogyne incognita

European Journal of Plant Pathology ◽

10.1007/s10658-021-02335-3 ◽

2021 ◽

Author(s):

Anil Baniya ◽

Soumi Joseph ◽

Larry Duncan ◽

William Crow ◽

Tesfamariam Mengistu

Keyword(s):

Caenorhabditis Elegans ◽

Sex Determination ◽

Meloidogyne Incognita ◽

Egg Production ◽

Target Genes ◽

Parasitic Nematode ◽

Plant Parasitic Nematode ◽

Root Knot Nematode ◽

Model Free ◽

Plant Parasitic

AbstractSex determination is a key developmental event in all organisms. The pathway that regulates sexual fate has been well characterized at the molecular level in the model free-living nematode Caenorhabditis elegans. This study aims to gain a preliminary understanding of sex-determining pathways in a plant-parasitic nematode Meloidogyne incognita, and the extent to which the roles of the sex determination genes are conserved in a hermaphrodite species, C. elegans, and plant-parasitic nematode species, M. incognita. In this study, we targeted two sex-determining orthologues, sdc-1 and tra-1 from M. incognita using RNA interference (RNAi). RNAi was performed by soaking second-stage juveniles of M. incognita in a solution containing dsRNA of either Mi-tra-1or Mi-sdc-1 or both. To determine the effect of RNAi of the target genes, the juveniles treated with the dsRNA were inoculated onto a susceptible cultivar of cowpea grown in a nutrient pouch at 28 °C for 5 weeks. The development of the nematodes was analyzed at different time points during the growth period and compared to untreated controls. Our results showed that neither Mi-sdc-1 nor Mi-tra-1 have a significant role in regulating sexual fate in M. incognita. However, the silencing of Mi-sdc-1 significantly delayed maturity to adult females but did not affect egg production in mature females. In contrast, the downregulation of Mi-tra-1 transcript resulted in a significant reduction in egg production in both single and combinatorial RNAi-treated nematodes. Our results indicate that M. incognita may have adopted a divergent function for Mi-sdc-1 and Mi-tra-1distinct from Caenorhabditis spp. However, Mi-tra-1 might have an essential role in female fecundity in M. incognita and is a promising dsRNA target for root-knot nematode (RKN) management using host-delivered RNAi.

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