DNA transposons drive genome evolution of the root-knot nematode Meloidogyne incognita

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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Expression profile of jasmonic acid-induced genes and the induced resistance against the root-knot nematode (Meloidogyne incognita) in tomato plants (Solanum lycopersicum) after foliar treatment with methyl jasmonate

Journal of Plant Physiology ◽

10.1016/j.jplph.2010.12.002 ◽

2011 ◽

Vol 168 (10) ◽

pp. 1084-1097 ◽

Cited By ~ 67

Author(s):

Taketo Fujimoto ◽

Yasuhiro Tomitaka ◽

Hiroshi Abe ◽

Shinya Tsuda ◽

Kazuyoshi Futai ◽

...

Keyword(s):

Jasmonic Acid ◽

Methyl Jasmonate ◽

Solanum Lycopersicum ◽

Induced Resistance ◽

Expression Profile ◽

Meloidogyne Incognita ◽

Root Knot Nematode ◽

Tomato Plants ◽

Foliar Treatment ◽

Induced Genes

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Transcriptional Changes of the Root-Knot Nematode Meloidogyne incognita in Response to Arabidopsis thaliana Root Signals

PLoS ONE ◽

10.1371/journal.pone.0061259 ◽

2013 ◽

Vol 8 (4) ◽

pp. e61259 ◽

Cited By ~ 22

Author(s):

Alice Teillet ◽

Katarzyna Dybal ◽

Brian R. Kerry ◽

Anthony J. Miller ◽

Rosane H. C. Curtis ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Meloidogyne Incognita ◽

Root Knot Nematode ◽

Root Signals ◽

Transcriptional Changes

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Evaluation of Blattisocius dolichus (Acari: Blattisociidae) for biocontrol of root-knot nematode, Meloidogyne incognita (Tylenchida: Heteroderidae)

BioControl ◽

10.1007/s10526-014-9581-z ◽

2014 ◽

Vol 59 (5) ◽

pp. 617-624 ◽

Cited By ~ 3

Author(s):

Chun-Ling Xu ◽

Yong-Liang Chen ◽

Xue-Nong Xu ◽

Dong-Wei Wang ◽

Hui Xie ◽

...

Keyword(s):

Meloidogyne Incognita ◽

Root Knot Nematode

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Systemically Induced Resistance and Microbial Competitive Exclusion: Implications on Biological Control

Phytopathology ◽

10.1094/phyto-04-11-0120 ◽

2012 ◽

Vol 102 (3) ◽

pp. 260-266 ◽

Cited By ~ 33

Author(s):

A. Martinuz ◽

A. Schouten ◽

R. A. Sikora

Keyword(s):

Meloidogyne Incognita ◽

Defense Mechanisms ◽

Root Colonization ◽

Competitive Exclusion ◽

Spatial Separation ◽

Agricultural Pests ◽

Root Knot Nematode ◽

Tomato Plants ◽

Split Root ◽

Induce Resistance

The root-knot nematode, Meloidogyne incognita, is among the most damaging agricultural pests, particularly to tomato. The mutualistic endophytes Fusarium oxysporum strain Fo162 (Fo162) and Rhizobium etli strain G12 (G12) have been shown to systemically induce resistance toward M. incognita. By using triple-split-root tomato plants, spatially separated but simultaneous inoculation of both endophytes did not lead to additive reductions in M. incognita infection. More importantly, spatially separated inoculation of Fo162 and G12 led to a reduction in Fo162 root colonization of 35 and 39% when G12 was inoculated on a separate root section of the same plant in two independent experiments. In an additional split-root experiment, spatial separation of Fo162 and G12 resulted in a reduction of Fo162 root colonization of approximately 50% over the water controls in two independent experiments. The results suggested that the suppressive activity of G12 on Fo162 and M. incognita is possibly related to the induction of specific plant defense mechanisms. Thus, although Fo162 and G12 have the ability to systemically repress M. incognita infection in tomato, they can be considered incompatible biocontrol agents when both organisms are present simultaneously on the same root system.

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