scholarly journals Root-knot nematode chemotaxis is positively regulated by l-galactose sidechains of mucilage carbohydrate rhamnogalacturonan-I

2021 ◽  
Vol 7 (27) ◽  
pp. eabh4182
Author(s):  
Allen Yi-Lun Tsai ◽  
Yuka Iwamoto ◽  
Yoichi Tsumuraya ◽  
Morihiro Oota ◽  
Teruko Konishi ◽  
...  
Keyword(s):  
High Specificity ◽  
Environmental Chemicals ◽  
Hydroxyl Groups ◽  
Agricultural Pests ◽  
Root Knot Nematode ◽  
Root Knot Nematodes ◽  
Pectic Polysaccharide ◽  
Rhamnogalacturonan I ◽  
Structures And Properties ◽  
Nematode Chemotaxis

Root-knot nematodes (RKNs) are plant parasites and major agricultural pests. RKNs are thought to locate hosts through chemotaxis by sensing host-secreted chemoattractants; however, the structures and properties of these attractants are not well understood. Here, we describe a previously unknown RKN attractant from flaxseed mucilage that enhances infection of Arabidopsis and tomato, which resembles the pectic polysaccharide rhamnogalacturonan-I (RG-I). Fucose and galactose sidechains of the purified attractant were found to be required for attractant activity. Furthermore, the disaccharide α-l-galactosyl-1,3-l-rhamnose, which forms the linkage between the RG-I backbone and galactose sidechains of the purified attractant, was sufficient to attract RKN. These results show that the α-l-galactosyl-1,3-l-rhamnose linkage in the purified attractant from flaxseed mucilage is essential for RKN attraction. The present work also suggests that nematodes can detect environmental chemicals with high specificity, such as the presence of chiral centers and hydroxyl groups.

Reactions of lines of Phaseolus atropurpureus to four species of root-knot nematode

1972 ◽  
Vol 23 (4) ◽  
pp. 623
Author(s):  
EM Hutton ◽  
WT Williams ◽  
LB Beall
Keyword(s):  
Lycopersicon Esculentum ◽  
Differential Resistance ◽  
Meloidogyne Arenaria ◽  
Root Knot Nematode ◽  
Root Knot Nematodes ◽  
Increased Susceptibility

In each of two years the reactions of 36 lines of Phaseolus atropurpureus to the four root-knot nematodes Meloidogyne arenaria, M. hapla, M. incognita, and M. javanica were studied. Seven of the experimental lines were common to the two years. Two known susceptible species, Phaseolus lathyroides and Lycopersicon esculentum (tomato cv. Grosse Lisse), were used as controls. Four macroscopic and four microscopic reactions were recorded on each occasion, and the results analysed. Resistance to the four nematodes was present in all lines of P. atropurpureus. There was also evidence of differential resistance between lines; some showed increased resistance to all nematodes except M. hapla, and others showed both increased susceptibility to M. hapla and increased resistance to M. javanica. The severity of attack on thc controls was significantly less in the second ycar. Several explanations for this are advanced.

scholarly journals Control of Root-knot Nematodes by Streptomyces: Screening of Root-knot Nematode-controlling Actinomycetes and Evaluation of Their Usefulness in a Pot Test

1999 ◽  
Vol 29 (2) ◽  
pp. 42-45 ◽  
Author(s):  
Kazuyoshi CHUBACHI ◽  
Makoto FURUKAWA ◽  
Shigeaki FUKUDA ◽  
Senji TAKAHASHI ◽  
Shoji MATSUMURA ◽  
...  
Keyword(s):  
Root Knot Nematode ◽  
Root Knot Nematodes

scholarly journals Histological Characterization of Resistance to Different Root-Knot Nematode Species Related to Phenolics Accumulation in Capsicum annuum

2005 ◽  
Vol 95 (2) ◽  
pp. 158-165 ◽  
Author(s):  
A. Pegard ◽  
G. Brizzard ◽  
A. Fazari ◽  
O. Soucaze ◽  
P. Abad ◽  
...  
Keyword(s):  
Resistance Gene ◽  
Capsicum Annuum ◽  
High Performance ◽  
Nematode Species ◽  
Susceptible Cultivar ◽  
Resistant Line ◽  
Root Knot Nematode ◽  
Resistance Response ◽  
Root Knot Nematodes ◽  
Chromatography Analysis

In the pepper Capsicum annuum CM334, which is used by breeders as a source of resistance to Phytophthora spp. and potyviruses, a resistance gene entirely suppresses reproduction of the root-knot nematode (Meloidogyne spp.). The current study compared the histological responses of this resistant line and a susceptible cultivar to infection with the three most damaging root-knot nematodes: M. arenaria, M. incognita, or M. javanica. Resistance of CM334 to root-knot nematodes was associated with unidentified factors that limited nematode penetration and with post-penetration biochemical responses, including the hypersensitive response, which apparently blocked nematode migration and thereby prevented juvenile development and reproduction. High-performance liquid chromatography analysis suggested that phenolic compounds, especially chlorogenic acid, may be involved in CM334 resistance. The response to infection in the resistant line varied with root-knot nematode species and was correlated with nematode behavior and pathogenicity in the susceptible cultivar: nematode species that quickly reached the vascular cylinder and initiated feeding sites in the susceptible cultivar were quickly recognized in CM334 and stopped in the epidermis or cortex. After comparing our data with those from other resistant pepper lines, we suggest that timing of the resistance response and the mechanism of resistance vary with plant genotype, resistance gene, and root-knot nematode species.

Genetic diversity of Meloidogyne spp. parasitising potato in Brazil and aggressiveness of M. javanica populations on susceptible cultivars

Nematology ◽  
2017 ◽  
Vol 19 (1) ◽  
pp. 69-80 ◽  
Author(s):  
Israel L. Medina ◽  
Cesar B. Gomes ◽  
Valdir R. Correa ◽  
Vanessa S. Mattos ◽  
Philippe Castagnone-Sereno ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Rapd Markers ◽  
Potato Production ◽  
Potato Cultivars ◽  
Root Knot Nematode ◽  
Root Knot Nematodes ◽  
Nematode Reproduction ◽  
Meloidogyne Spp ◽  
Prevalent Species ◽  
Reproduction Factor

Root-knot nematodes (Meloidogyne spp.) significantly impact potato production worldwide and in Brazil they are considered one of the most important group of nematodes affecting potatoes. The objectives of this study were to survey Meloidogyne spp. associated with potatoes in Brazil, determine their genetic diversity and assess the aggressiveness of M. javanica on two susceptible potato cultivars. Fifty-seven root-knot nematode populations were identified using esterase phenotyping, including Meloidogyne javanica, M. incognita, M. arenaria and M. ethiopica. Overall, root-knot nematodes were present in ca 43% of sampled sites, in which M. javanica was the most prevalent species, and the phenotypes Est J3, J2a and J2 occurred in 91.2, 6.7 and 2.1% of the positive samples, respectively. Other species, such as M. incognita, M. arenaria and M. ethiopica, were found less frequently and occurred at rates of 6.4, 4.3 and 2.1% of the samples, respectively. Sometimes, M. javanica was found in mixtures with other root-knot nematodes in ca 10.6% of sites containing Meloidogyne. After confirming the identification of 17 isolates of M. javanica and one isolate each of M. incognita, M. arenaria and M. ethiopica by SCAR markers, the populations were used to infer their genetic diversity using RAPD markers. Results revealed low intraspecifc genetic diversity among isolates (13.9%) for M. javanica. Similarly, M. javanica sub-populations (J2a) clustered together (81% of bootstrap), indicating subtle variation from typical J3 populations. The aggressiveness of four populations of M. javanica from different Brazilian states on two susceptible potato cultivars was tested under glasshouse conditions. Results indicated differences in aggressiveness among these populations and showed that potato disease was proportional to nematode reproduction factor.

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

2012 ◽  
Vol 102 (3) ◽  
pp. 260-266 ◽  
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.

scholarly journals Genome expression dynamics reveals parasitism regulatory landscape of the root-knot nematode Meloidogyne incognita and a promoter motif associated with effector genes

2021 ◽  
Author(s):  
Martine Da Rocha ◽  
Caroline Bournaud ◽  
Julie Dazeniere ◽  
Peter Thorpe ◽  
Clement Pellegrin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Meloidogyne Incognita ◽  
Life Stage ◽  
Regulation Of Gene Expression ◽  
Root Knot Nematode ◽  
Root Knot Nematodes ◽  
Control Of Gene Expression ◽  
Precise Control ◽  
Effector Genes ◽  
Spatio Temporal

Root-knot nematodes are the major contributor to the crop losses caused by nematodes. Root-knot nematodes secrete effectors into the plant, derived from two sets of pharyngeal gland cells, to manipulate host physiology and immunity. Successful completion of the life cycle, involving successive molts from egg to adult, covers morphologically and functionally distinct stages and will require precise control of gene expression, including effectors. The details of how root-knot nematodes regulate transcription remain sparse. Here, we report a life stage-specific transcriptome of Meloidogyne incognita. Combined with an available annotated genome, we explore the spatio-temporal regulation of gene expression. We reveal gene expression clusters and predicted functions that accompany the major developmental transitions. Focusing on effectors, we identify a putative cis-regulatory motif associated with expression in the dorsal glands: providing an insight into effector regulation. We combine the presence of this motif with several other criteria to predict a novel set of putative dorsal gland effectors. Finally, we show this motif, and thereby its utility, is broadly conserved across the Meloidogyne genus and termed it Mel-DOG. Taken together, we provide the first genome-wide analysis of spatio-temporal gene expression in a root-knot nematode, and identify a new set of candidate effector genes that will guide future functional analyses.

scholarly journals A new root-knot nematode, Meloidogyne vitis sp. nov. (Nematoda: Meloidogynidae), parasitizing grape in Yunnan

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0245201
Author(s):  
Yanmei Yang ◽  
Xianqi Hu ◽  
Pei Liu ◽  
Li Chen ◽  
Huan Peng ◽  
...  
Keyword(s):  
New Species ◽  
Rapid Identification ◽  
Root Knot Nematode ◽  
Morphometric Traits ◽  
Head Region ◽  
Root Knot Nematodes ◽  
Lateral Field ◽  
Sequence Characterized Amplified Region ◽  
Second Stage ◽  
Labial Disc

An unknown root-knot nematode was found at high density on grape roots collected from Yunnan Province. Morphometric traits and measurements, isozyme phenotypes, and molecular analysis clearly differentiated this nematode from previously described root-knot nematodes. This new species is described, illustrated and named Meloidogyne vitis sp. nov. The new species can be distinguished from other Meloidogyne spp. by a unique combination of characters. Females display a prominent neck, an excretory pore is located on the ventral region between 23rd and 25th annule behind lips, an EP/ST ratio of approximately 2.5 (1.98–2.96), a perineal pattern with two large and prominent phasmids, and a labial disc fused with the medial lips to form a dumbbell-shaped structure. Males display an obvious head region, a labial disc fused with the medial lips to form a dumbbell-shaped structure, no lateral lips, a prominent slit-like opening between the labial disc and medial lips, a distinct sunken appearance of the middle of the medial lips, and four incisures in the lateral field. Second-stage juveniles are characterized by a head region with slightly wrinkled mark, a labial disc fused with the medial lips to form a dumbbell-shaped structure, a slightly sunken appearance of the middle of the medial lips, a slit-like amphidial openings between the labial disc and lateral lips, and four incisures in the lateral field. The new species has rare Mdh (N3d) and Est phenotypes (VF1). Phylogenetic analysis based on ITS1-5.8S-ITS2, D2D3 fragments of rDNA, and coxI and coxII fragments of mtDNA sequences clearly separated the new species from other root-knot nematodes, and the closest relative was Meloidogyne mali. Meloidogyne mali was collected for amplifying these sequences as mentioned above, which were compared with the corresponding sequences of new species, the result showed that all of these sequences with highly base divergence (48–210 base divergence). Moreover, sequence characterized amplified region (SCAR) primers for rapid identification of this new species were designed.

scholarly journals Assessment of the Potential of Eco-Friendly Nematicides in the Management of Root-Knot Nematodes on French Beans in Kenya

2019 ◽  
Vol 7 (1) ◽  
pp. 62-67
Author(s):  
E. O. Ogumo ◽  
W. M. Muiru ◽  
J. W. Kimenju ◽  
D. M. Mukunya
Keyword(s):  
Reproductive Potential ◽  
Negative Control ◽  
French Bean ◽  
Economic Losses ◽  
Root Knot Nematode ◽  
Population Densities ◽  
Root Knot Nematodes ◽  
French Beans ◽  
Wide Range ◽  
Significant Difference

Root-knot nematodes (RKN) (Meloidogyne spp) are a serious pest causing heavy economic losses in a wide range of agricultural crops. A trial was carried out to evaluate the effectiveness of various eco-friendly nematicides in the management of RKN affecting French bean. The field trial was carried out in two seasons with the following treatments; Rigel-G (salicylic acid), Phyto Protect (Sesame oil extract), Mytech (Paecilomyces lilacinus), Neemraj 0.3% (Azadirachtin), Vydate® (Oxamyl) as a positive control and an untreated control. Various rates; Rigel –G (2.5 ml/l), Phyto Protect (10 l/ha), Mytech (125 g/ha) Neemraj 0.3% (3L/ha) and Vydate® (6 l/ha) of treatments were administered and damage on plants was assessed based on galling indices, crop biomass and yield whereas nematode reproductive potential was assessed based on the J2 counts. There was no significant difference (P ≥ 0.05) in the nematode population densities and galling indices observed among the eco-friendly nematicides and the conventional nematicide (Vydate®). Eco-friendly nematicides had a significant (P ≤ 0.05) reduction of RKN J2 population densities compared to the negative control. The negative control had the highest mean of root-knot nematode densities (240 RKN/200 cc soil) and a galling index of 3.77 while Vydate and Neemraj had the lowest mean density (40 RKN/200 cc soil) in the first season. Similar results were observed in the second season with control having the highest RKN J2 population densities (285 RKN/200 cc soil) and a galling index of 3.89 and Vydate had the lowest (23 RKN/200 cc soil). The results of this study clearly indicate that eco-friendly nematicides can be fully adopted to suppress RKN in French beans as alternatives to conventional nematicides.

scholarly journals Application of Biogas Digestate with Rice Straw Mitigates Nitrate Leaching Potential and Suppresses Root-Knot Nematode (Meloidogyne incognita)

Agronomy ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 227 ◽  
Author(s):  
Yuexi Wang ◽  
Seiya Chikamatsu ◽  
Tuya Gegen ◽  
Kozue Sawada ◽  
Koki Toyota ◽  
...  
Keyword(s):  
Rice Straw ◽  
Nitrate Leaching ◽  
Meloidogyne Incognita ◽  
Application Rate ◽  
Pig Manure ◽  
Test Plant ◽  
Root Knot Nematode ◽  
Root Knot Nematodes ◽  
Leaching Potential ◽  
Biogas Digestate

This study investigated the effects of biogas digestate application to soil with rice straw on nitrate leaching potential and nematicidal activity toward root-knot nematodes Meloidogyne incognita. The following seven treatments were set up: (i) control (CONT); (ii) chemical fertilizer (CF); (iii) wet biogas digestate derived from pig manure (WBD); (iv) and (v) dry biogas digestate derived from a mixture of pig manure and rice straw at an initial C/N ratio of 20 and 30 (DBD20 and DBD30); (vi) and (vii) DBD20 mixed with rice straw to adjust the C/N ratio to 16 (Mix1) and 30 (Mix2), respectively. The application rate of CF and digestates was adjusted to 200 mg N kg−1 soil based on the inorganic ammonium nitrogen contents. Nitrate contents readily increased in all the treatments with incubation, except for Mix2, and those at day 90 were decreased with increasing initial labile C contents. Garden balsam was grown as a test plant for root-knot nematodes using the soils at day 90 and the results showed that the gall index was significantly lower in Mix2 and Mix1 than in CF. These results suggest that dry digestate mixed with rice straw might have potential for lower nitrate leaching and nematicidal properties.

Yellow Nutsedge Response to Southern Root-Knot Nematodes, Chile Peppers, and Metolachlor

Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 534-540 ◽  
Author(s):  
Jill Schroeder ◽  
Michael J. Kenney ◽  
Stephen H. Thomas ◽  
Leigh Murray
Keyword(s):  
Host Plant ◽  
Plant Root ◽  
Root Systems ◽  
Root Mass ◽  
Root Knot Nematode ◽  
Root Knot Nematodes ◽  
Yellow Nutsedge ◽  
Greenhouse Experiments ◽  
Shoot Number ◽  
Chile Peppers

Greenhouse experiments showed that yellow nutsedge shoot number and shoot and root dry weights were reduced by root-knot nematodes and chile peppers. Root-knot nematodes increased and chile peppers decreased the number of yellow nutsedge tubers. Yellow nutsedge tuber germination was reduced by chile peppers but not by root-knot nematodes. Yellow nutsedge established from root-knot nematode-infected tubers produced more tubers than noninfected tubers. Root-knot nematode populations became established on yellow nutsedge root systems when plants were established from tubers previously cultured with root-knot nematodes. Metolachlor stunted chile peppers, eliminated yellow nutsedge, and influenced root-knot nematode populations through reduction of host plant root mass. However, when root-knot nematodes were present, yellow nutsedge tuber germination was not affected by metolachlor. This research indicates that the pests do not exist independently and that their management may be interrelated.

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