Epidemics of Meloidogyne brasilensis in Central Brazil on Processing Tomato Hybrids That Have the Root-Knot Nematode Mi Resistance Gene

The species Meloidogyne brasilensis Charchar & Eisenback 2002 was described as causing root rot, severe wilt, and numerous galls in pea (Pisum sativum L.) in Brasília-Federal District and tomato (Solanum lycopersicum L.) cv. Rossol (known to have the root-knot nematode resistance Mi gene) in Londrina-Paraná State, Brazil. To our knowledge, this current work is the first report of the epidemics on tomato hybrids that have the Mi gene caused by infection of M. brasilensis in central Brazil. Samples were obtained from fields with two commercial hybrids that have the Mi gene (‘Calroma’ and ‘Nemapride’) that were cultivated under center-pivot irrigation in Silvânia, Goiás State. These hybrids exhibited slow vegetative development and malformed roots because of the high number of large galls. Symptomatic plants were collected from a tomato crop area of more than 100 ha. Random sampling indicated field sectors with up to 100% of symptomatic plants. Morphological and morphometric evaluations of this Meloidogyne population were carried out with the female perineal pattern, stylet, and excretory pore and also with the male body traits, labial disc, and stylet. The esterase phenotype was unique for this population with four clear bands (J. M. Charchar, unpublished data). Altogether, the morphological and biochemical characteristics of this population were in agreement with that reported for M. brasilensis (1). Koch's postulates were fulfilled using tomato ‘Rutgers’ (susceptible) and ‘Rossol' (with the Mi resistance locus) under greenhouse conditions. The massive use of tomato hybrids with the Mi gene could be a strong selection factor favoring this pathogen under growing conditions in central Brazil. Germplasm screen searching for sources of resistance specific to this nematode species is advisable. Reference: (1) J. M. Charchar and J. D. Eisenback. Nematology 4:629, 2002.

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Effect of the Mi gene on reproduction of Meloidogyne hispanica on tomato genotypes

Nematology ◽

10.1163/138855411x566449 ◽

2011 ◽

Vol 13 (8) ◽

pp. 939-949 ◽

Cited By ~ 9

Author(s):

Maria Clara Vieira dos Santos ◽

Rosane H.C. Curtis ◽

Isabel M. de O. Abrantes ◽

Carla M. Maleita ◽

Stephen J. Powers

Keyword(s):

Nematode Species ◽

Nematode Resistance ◽

Management Programme ◽

Root Knot Nematode ◽

Rf Values ◽

Gall Index ◽

Mi Gene ◽

Gene Status ◽

Reproduction Factor ◽

Tomato Genotypes

AbstractThe root-knot nematode resistance (Mi) gene was screened in 25 tomato genotypes of Solanum lycopersicum, by amplification of REX-1 and Mi23 markers. Ten heterozygous tomato genotypes (Mimi), nine homozygous (MiMi) at the Mi locus and six lacking the Mi gene for resistance to root-knot nematode were identified using the marker REX-1. The results obtained with Mi23 marker confirmed the Mi gene status of the tomato genotypes, except for genotype Valouro RZ F1 that was homozygous (MiMi) and heterozygous (Mimi) at the Mi locus when using the REX-1 and Mi23 markers, respectively. The pathogenicity of Meloidogyne hispanica on the 25 tomato genotypes was assessed 60 days after inoculation with 5000 eggs on the basis of root gall index (GI) and reproduction factor (Rf). All the tomato genotypes were susceptible (excellent or good hosts), with GI > 4 and Rf > 2, except the genotype Rapit (Mimi), considered as resistant/hypersensitive (poor host). In this genotype, the nematode induced galls (GI = 4) on its roots and a small number of eggs were produced (Pf = 3085 ± 485). Significant differences in reproduction were detected between the Mi allelic conditions and genotypes within Mi allelic conditions. The increasing number of Mi alleles (0, 1 or 2) is associated with decreasing Rf, which suggests a possible dosage effect of the Mi gene. The variability observed in the Rf values for MiMi tomato genotypes may reflect an influence of the genetic background of the plants containing the Mi gene. Ten of the 25 tomato genotypes with Mi gene are commercially available. However, only Rapit can be used to control the three most common Meloidogyne spp. and inhibit the increasing of M. hispanica populations, and may have potential to be included in an integrated pest management programme. However, it is advisable to evaluate the pathogenicity of local populations of this nematode species associated with different environmental factors.

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Resistance in Peanut Cultivars and Breeding Lines to Three Root-Knot Nematode Species

Plant Disease ◽

10.1094/pdis-92-4-0631 ◽

2008 ◽

Vol 92 (4) ◽

pp. 631-638 ◽

Cited By ~ 4

Author(s):

W. B. Dong ◽

C. C. Holbrook ◽

P. Timper ◽

T. B. Brenneman ◽

Y. Chu ◽

...

Keyword(s):

Durable Resistance ◽

Nematode Species ◽

Nematode Resistance ◽

Root Knot Nematode ◽

Sources Of Resistance ◽

Breeding Lines ◽

Sequence Characterized Amplified Region ◽

Race 1 ◽

Meloidogyne Spp ◽

Peanut Cultivars

Three major species of root-knot nematode infect peanut: Meloidogyne arenaria race 1, M. hapla, and M. javanica race 3. Sources of resistance to all three nematodes are needed for developing novel peanut cultivars with broad resistance to Meloidogyne spp. Cultivars and breeding lines of peanut were evaluated for resistance to M. arenaria, M. hapla, and M. javanica in the greenhouse and in the laboratory. Twenty-six genotypes with some resistance to M. arenaria, M. javanica, or M. hapla were identified from 60 accessions based on average eggs per gram of root and gall index relative to a susceptible control. Among these, 14 genotypes were moderately to highly resistant to all three species, 5 genotypes were resistant to M. arenaria and M. javanica, 2 genotypes were resistant to M. javanica and M. hapla, 1 genotype was resistant M. arenaria alone, and 4 genotypes were resistant to M. hapla alone. Reproduction of M. arenaria on lines NR 0817, C724-19-11, and D108 was highly variable, indicating that these genotypes likely were heterogeneous for resistance. COAN, NemaTAM, C724-25-8, and the M. arenaria-resistant plants of C724-19-11 contained the dominant sequence-characterized amplified region marker (197/909) for nematode resistance. Results with the molecular markers indicate that the high resistance to M. arenaria in GP-NC WS 6 may be different from the resistance in COAN, NemaTAM, and C724-25-8. Resistance to M. arenaria was correlated with resistance to M. javanica in peanut, whereas resistance to M. hapla was not correlated with the resistance to either M. arenaria or M. javanica. The resistant selections should be valuable sources for pyramiding resistance genes to develop new cultivars with broad and durable resistance to Meloidogyne spp.

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Meloidogyne lopezi n. sp. (Nematoda: Meloidogynidae), a new root-knot nematode associated with coffee (Coffea arabica L.) in Costa Rica, its diagnosis and phylogenetic relationship with other coffee-parasitising Meloidogyne species

Nematology ◽

10.1163/15685411-00002794 ◽

2014 ◽

Vol 16 (6) ◽

pp. 643-661 ◽

Cited By ~ 11

Author(s):

Danny A. Humphreys-Pereira ◽

Lorena Flores-Chaves ◽

Danny A. Humphreys-Pereira ◽

Lorena Flores-Chaves ◽

...

Keyword(s):

Costa Rica ◽

16S Rrna ◽

Coffea Arabica ◽

Phylogenetic Analyses ◽

Mitochondrial Gene ◽

Restriction Enzymes ◽

Nematode Species ◽

Male Body ◽

Root Knot Nematode ◽

Pcr Rflp

Coffee (Coffea arabica L. cv. Catuai) seedlings with abundant small root galls caused by an unknown root-knot nematode were found in southern Costa Rica. Morphology, esterase and malate dehydrogenase isozyme phenotypes and DNA markers differentiated this nematode from known Meloidogyne spp. A new species, M. lopezi n. sp., with common name Costa Rican root-knot nematode, is suggested. Meloidogyne lopezi n. sp. is distinguished from other coffee-associated Meloidogyne spp. by size of female lips and stylet, male body length and stylet and second-stage juvenile body and tail morphology. The region of the mitochondrial genome between COII and 16S rRNA showed a unique amplicon size of 1370 bp, and digestions with restriction enzymes HinfI, AluI, DraI and DraIII revealed characteristic PCR-RFLP patterns that differed from the tropical root-knot nematode species M. arabicida, M. incognita, M. izalcoensis, M. javanica and M. paranaensis. Characterisation of the protein-coding map-1 gene and phylogenetic analyses suggested that M. lopezi n. sp. might reproduce by mitotic parthenogenesis. Phylogenies estimated using Bayesian analyses based on the region between the COII and 16S rRNA mitochondrial genes, as well as the 18S and 28S ribosomal nuclear genes, indicated that M. lopezi n. sp. is closely related to other tropical Meloidogyne spp. that infect coffee, especially M. arabicida, M. izalcoensis and M. paranaensis from Central and South America. Isozyme analyses and PCR-RFLP of the COII-16S rRNA mitochondrial gene region enable a clear diagnostic differentiation between these species.

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

Phytopathology ◽

10.1094/phyto-95-0158 ◽

2005 ◽

Vol 95 (2) ◽

pp. 158-165 ◽

Cited By ~ 80

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.

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Sources of resistance to Fusarium wilt and root-knot nematode in indigenous chickpea germplasm

Plant Genetic Resources ◽

10.1017/s1479262112000263 ◽

2012 ◽

Vol 10 (3) ◽

pp. 258-260 ◽

Cited By ~ 5

Author(s):

Mohar Singh ◽

Z. Khan ◽

Krishna Kumar ◽

M. Dutta ◽

Anju Pathania ◽

...

Keyword(s):

Fusarium Wilt ◽

Rating Scale ◽

Resistance Breeding ◽

Practical Method ◽

Root Knot Nematode ◽

Sources Of Resistance ◽

Chickpea Wilt ◽

Breeding Programmes ◽

Race 1 ◽

Moderately Resistant

Fusarium wilt caused by Fusarium oxysporum, Schlecht. emend. Snyd. & Hans. f. sp. ciceri is prevalent in most chickpea-growing countries and is a major devastating disease. Host plant resistance is the most practical method of disease management. Indigenous chickpea germplasm reveals a heterogeneous genetic make-up and the response of resistance to wilt is an unexplored potential source for disease resistance. There are 70 indigenous germplasm lines selected on the basis of their agronomic performance and diverse areas of collections in the country. Of these, four accessions had a highly resistant score of 1 and six had a score of 3 using a 1–9 rating scale, indicating their level of resistance to Fusarium wilt (race 4). Other germplasm accessions of chickpea were found to be moderately resistant to highly susceptible disease reaction. Likewise, the same set of germplasm was also screened for Meloidogyne incognita (race 1) using pot culture under controlled condition. Only one accession was found to be resistant to this pest. These resistant gene sources can be utilised effectively for race-specific chickpea wilt and root-knot resistance breeding programmes.

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Host suitability of summer cover crops to Meloidogyne arenaria, M. enterolobii, M. incognita and M. javanica

Nematology ◽

10.1163/15685411-bja10122 ◽

2021 ◽

pp. 1-9

Author(s):

Hung X. Bui ◽

Johan A. Desaeger

Keyword(s):

Cover Crops ◽

Nematode Species ◽

Host Suitability ◽

Parasitic Nematodes ◽

Plant Parasitic Nematodes ◽

Root Knot Nematode ◽

Sunn Hemp ◽

Host Status ◽

Susceptible Control ◽

Sorghum Sudangrass

Summary Cover crops can be a useful tool for managing plant-parasitic nematodes provided they are poor or non-hosts for the target nematode species. A glasshouse experiment was done to determine the host status of four common cover crops in Florida, sunn hemp, cowpea, sorghum sudangrass and sunflower, to pure populations of four common tropical root-knot nematode (RKN) species Meloidogyne javanica (Mj), M. incognita (Mi), M. enterolobii (Me) and M. arenaria (Ma). Tomato was included as a susceptible control. Eight weeks after nematode inoculation (WAI), tomato showed the highest root gall damage for all tested RKN species, with gall indices (GI) between 7 (Ma) and 8.5 (Me) and reproduction factor (RF) ranging from 20 (Ma) to 50 (Mj). No visible root galls were observed for any of the RKN species on sunn hemp and sorghum sudangrass at 8 WAI. However, Mj and Mi were able to reproduce slightly on sorghum sudangrass (RF = 0.02 and 0.79, respectively). Sunflower and cowpea were infected by all four tested RKN species, but host suitability varied. Sunflower root galling ranged from 1.1 (Me) to 4.5 (Mj) and RF = 3.2 (Me) to 28.7 (Mj), while cowpea root galling ranged from 0.6 (Mi) to 5.1 (Me) and RF = 0.8 (Mi) to 67.3 (Mj). Sunn hemp and, to a lesser extent, sorghum sudangrass were poor hosts to all four tested RKN species. Sunflower was a good host to all RKN species, but root gall damage and RF were lowest for Me. Cowpea was a good host to Mj, Me and Ma, but a poor host to Mi. Our results confirm and stress the importance of RKN species identification when selecting cover crops as an RKN management strategy.

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Genetic Diversity, Identification and Utilization of Novel Genetic Resources for Resistance to Meloidogyne incognita in Mulberry (Morus spp.)

Plant Disease ◽

10.1094/pdis-11-20-2515-re ◽

2021 ◽

Author(s):

Gondi S Arunakumar ◽

Belaghihalli Nanjappa Gnanesh ◽

Haniyambadi B Manojkumar ◽

Doss S. Gandhi ◽

Mogili Thallapally ◽

...

Keyword(s):

Ssr Markers ◽

Resistance Breeding ◽

Field Resistance ◽

Infested Soil ◽

Root Knot Nematode ◽

Sources Of Resistance ◽

Molecular Variance ◽

Morus Spp ◽

Principle Coordinate Analysis ◽

Germplasm Accessions

Mulberry (Morus spp.) is an important crop in the sericulture industry as the leaves constitute the primary feed for the silkworm. The availability of diverse genetic sources of resistance to root- knot nematode (RKN; Meloidogyne spp.) are very scanty and therefore, a set of 415 varied exotic and indigenous germplasm accessions were screened under glasshouse conditions. Twenty one accessions were identified as highly resistant and 48 were resistant, the highest numbers of highly resistant/resistant accessions were found in Morus alba. Further, thirty accessions based on rooting ability were evaluated for field resistance at four different locations with infested soil. Finally, eight germplasm accessions; BR-8, Karanjtoli-1, Hosur-C8, Nagalur Estate, Tippu, Calabresa, Thai Pecah and SRDC-3 were identified as potential genetic sources in RKN resistance breeding programs or as resistant rootstock for the establishment of mulberry gardens. Sixteen SSR markers analyzed among the 77 resistant and susceptible accessions, generated 55 alleles, ranging from 2 to 5 with an average of 3.43 alleles per locus. Principle coordinate analysis grouped the accessions on the basis of RKN susceptible and resistant to a greater extent. The RKN susceptible accessions exhibited higher variability as compared to resistant accessions and they were more dispersed. Analysis of molecular variance showed that maximum molecular variance (78%) within the population and 22% between populations. Results of this study indicate that SSR markers are reliable for assessing genetic variability among the RKN resistant and susceptible mulberry accessions.

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Comparative study of the zooplankton composition of six lacustrine ecosystems in Central Brazil during the dry season

Revista Brasileira de Biologia ◽

10.1590/s0034-71082000000100013 ◽

2000 ◽

Vol 60 (1) ◽

pp. 101-111 ◽

Cited By ~ 11

Author(s):

F. L. do R. M. STARLING

Keyword(s):

Zooplankton Community ◽

Federal District ◽

Dry Season ◽

Zooplankton Species ◽

Waste Stabilisation Ponds ◽

Central Brazil ◽

Morphometric Features ◽

Santa Maria ◽

Sørensen Index

Zooplankton community from six lacustrine ecosystems located in Federal District (Central Brazil) was studied based on samples collected during the dry season (July to September). A total of 71 taxa were recorded: 44 rotifers, 17 cladocerans and 10 copepods. The highest number of zooplankton species was recorded in oligotrophic Bonita Pond (32 species) and the lowest number in hypertrophic waste stabilisation ponds (7 species). This tendency of decreasing the diversity with increasing trophic level was consistent with a cluster analysis of the samples based on Sorensen index of similarity. From the overall similarity dendrogram, two groups of ecosystems were distinguished: one containing the natural ponds Bonita and Formosa and the other comprising the reservoirs Santa Maria, Descoberto and Paranoá. The role of morphometric features in determining the zooplankton community in such lacustrine ecosystems was also discussed.

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Prevalence of human papillomavirus type 16 variants in the Federal District, Central Brazil

Memórias do Instituto Oswaldo Cruz ◽

10.1590/s0074-02762004000300007 ◽

2004 ◽

Vol 99 (3) ◽

pp. 281-282 ◽

Cited By ~ 15

Author(s):

Márcio R Cruz ◽

Daniela M Cerqueira ◽

Waldenor B Cruz ◽

Geni NL Camara ◽

Marcelo M Brígido ◽

...

Keyword(s):

Human Papillomavirus ◽

Federal District ◽

Central Brazil ◽

Human Papillomavirus Type 16

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Single pass cDNA sequencing - a powerful tool to analyse gene expression in preparasitic juveniles of the southern root-knot nematode Meloidogyne incognita

Nematology ◽

10.1163/156854101750236259 ◽

2001 ◽

Vol 3 (2) ◽

pp. 129-139 ◽

Cited By ~ 38

Author(s):

Jaap Bakker ◽

Fred Gommers ◽

Geert Smant ◽

Pierre Abad ◽

Marie-Noëlle Rosso ◽

...

Keyword(s):

Gene Expression ◽

Cdna Library ◽

Meloidogyne Incognita ◽

Sequence Data ◽

Homo Sapiens ◽

Large Fraction ◽

Nematode Species ◽

Cdna Libraries ◽

Parasitic Nematodes ◽

Root Knot Nematode

AbstractExpressed sequence tags (EST) have been widely used to assist in gene discovery in various organisms (e.g., Arabidopsis thaliana, Caenorhabditis elegans, Mus musculus, and Homo sapiens). In this paper we describe an EST project, which aims to investigate gene expression in Meloidogyne incognita at the onset of parasitism. Approximately 1000 5′-end sequence tags were produced from a cDNA library made of freshly hatched preparasitic second stage juveniles (J2). The EST were identified in the primary transformants of the cDNA library, and assigned to nine different functional groups, including (candidate) parasitism genes. A large fraction of the EST (45%) did not have a putative homologue in public databases. Sixty five percent of the EST that could be clustered into a functional group had putative homologues in other nematode species. EST were found for virtually all parasitism related genes that have been cloned from M. incognita to date. In addition, several novel genes were tagged, including a xylanase and a chitinase gene. The efficiency of EST projects, which produce sequence data for thousands of genes in months time without any difficult pre-selections of mRNA pools, makes random sequencing cDNA libraries a superior method to identify candidates for parasitism related genes in plant-parasitic nematodes. The sequences in this paper are retrievable from Genbank with the accession numbers BE191640 to BE191741, BE217592 to BE217720, BE225324 to BE225598, BE238852 to BE239221, and BE240829 to BE240865.

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