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Pathogenicity and reproductive fitness of Pratylenchus brachyurus on cowpea

SIQUEIRA, Kercya Maria Simoes de; INOMOTO, Mario Massayuki
Fonte: BRILL ACADEMIC PUBLISHERS Publicador: BRILL ACADEMIC PUBLISHERS
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.23%
The lesion nematode Pratylenchus brachyurus is widespread in cowpea plantations throughout the tropics and sub-tropics. However, the pathogenicity of P. brachyurus on cowpea has been scarcely studied. In this work, it was demonstrated in two glasshouse experiments that an isolate (Pb-20) of P brachyurus was pathogenic to cowpea cv. IPA-206, adversely affecting the plant growth and pod formation and filling. Initial population levels of 5000 and 15 000 nematodes per plant caused reduction of root growth and typical decay of root tissue. The third experiment demonstrated that all six cowpea cultivars selected for evaluation supported reproduction of three isolates of P. brachyurus (Pb-20, Pb-21 and Pb-23) in their roots, although the reproduction factor values obtained indicated that they were dissimilar in their reproductive fitness. Low resistance to R brachyurus was reported for at least one tested cultivar, but apparently of an insufficient degree to be effective for field management of the nematode.

Reação de culturas de cobertura utilizadas no sistema de plantio direto ao nematóide das lesões Pratylenchus brachyurus e ao nematóide das galhas, Meloidogyne incognita; Host status of cover crops used in no tillage system to lesion nematode Pratylenchus brachyurus and to root-knot nematode Meloidogyne incognita

Borges, Dárcio de Carvalho
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 30/09/2009 PT
Relevância na Pesquisa
46.31%
Na região dos cerrados, as principais culturas de cobertura utilizadas para a produção de palha no sistema de plantio direto são o milheto (Pennisetum glaucum R. BR.) e as aveias (Avenas spp.). No entanto, a resposta dessas espécies vegetais frente ao nematóide das lesões (Pratylenchus brachyurus) e o das galhas (Meloidogyne incognita) são escassas. O objetivo do presente trabalho é de verificar a resposta de genótipos de milhetos, aveias e outras coberturas vegetais a Pratylenchus brachyurus e de aveias a Meloidogyne incognita sob condições controladas. Desenvolveram-se quatro experimentos no total, no experimento 1, os cultivares de milhetos testados foram resistentes ao nematóide (FR<1,0) com exceção da cultivar ADR 500 (população BA). No experimento 2, as aveias pretas contribuíram para a redução populacional (resistentes) de P. brachyurus, fato oposto, pode ser verificado para as aveias branca e amarela (suscetíveis). No terceiro experimento, diferentemente do verificado no experimento 1, os milhetos se mostraram suscetíveis a P. brachyurus, e, o sorgo BRS-800 foi a cobertura que mais incrementou a densidade do nematóide, equiparando-se estatisticamente com a soja BRS 133. No quarto experimento, verificou-se aumento da densidade das três populações de M. incognita nas aveias pretas testadas...

Reação de hospedeiro de espécies de eucalipto a Pratylenchus brachyurus e Meloidogyne incognita; Host-status of eucalyptus species to Pratylenchus brachyurus and Meloidogyne incognita

Souza, Victor Hugo Moura de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 16/01/2015 PT
Relevância na Pesquisa
46.32%
O gênero Eucalyptus possui diversas espécies que apresentam grande valor comercial, sendo utilizado principalmente para produção de energia (carvão e lenha) e celulose-papel. Na literatura, entretanto, existem poucas informações acerca de nematoses nessa cultura. Além dessa carência e de sua importância econômica, o eucalipto é comumente cultivado em locais de alta incidência de Pratylenchus brachyurus e Meloidogyne incognita, além de ser consorciado com diversas outras culturas intolerantes, como por exemplo a soja. Dessa forma há uma necessidade de conhecer a reação das espécies de eucalipto a estes nematoides. Dito isso, o presente trabalho teve por objetivo testar a reação de algumas espécies de eucalipto a P. brachyurus e M.incognita. Foram realizados 6 experimentos, 5 envolvendo o nematoide das lesões e 1 com o nematoide de galhas. Os tratamentos foram inoculados com uma população inicial de nematoides e, após 90 dias, estimava-se o fator de reprodução (FR) e nematoides por grama de raiz (Nem/g). Adotou-se o critério baseado em Oostenbrink (1966), onde a espécie foi considerada suscetível quando apresenta FR >= 1 e resistente quando FR < 1. Dos eucaliptos testados, 6 apresentaram reação suscetível e 4 reação resistente para P. brachyurus. As espécies com maiores FR estão entre as mais utilizadas no Brasil...

Reação de porta-enxertos de videira a Pratylenchus brachyurus e Pratylenchus zeae

Puerari, Heriksen H.; Dias-Arieira, Claudia R.; Moura, Mara F.; Biela, Fabio; Chiamolera, Fernando M.; Cunha, Tatiana P.L. da
Fonte: Sociedade Brasileira de Fitopatologia Publicador: Sociedade Brasileira de Fitopatologia
Tipo: Artigo de Revista Científica Formato: 220-222
POR
Relevância na Pesquisa
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Nesse trabalho, o objetivo foi avaliar a reação de oito porta-enxertos de videira aos nematoides das lesões radiculares. As estacas dos porta-enxertos Kober, SO4, 101-14, R99, 420-A, Rupestris du Lot, Riparia do Traviú e Telek 5C, cedidas pelo Centro APTA de Frutas/IAC, foram plantadas em vasos contendo mistura de solo:areia na proporção 2:1 (v:v) e mantidas em casa de vegetação. Após quatro meses, os porta-enxertos foram inoculados com 1.200 espécimes de Pratylenchus brachyurus ou P. zeae, e o milho foi usado para comprovar a viabilidade do inóculo. Aos 180 dias após a inoculação, avaliou-se o número de nematoides por sistema radicular e em 100 cm³ de solo. O milho foi avaliado aos 90 dias após a inoculação e cada vaso recebeu uma nova planta, que foi avaliada juntamente com os porta-enxertos. No milho, as populações finais de P. brachyurus e P. zeae foram respectivamente iguais a 8.040 e 6.940 indivíduos. Todos os porta-enxertos comportaram-se como imunes a P. brachyurus e P. zeae, isto é, a população final dos nematoides e o fator de reprodução foram iguais a zero. Recuperaram-se seis e 11 espécimes de P. zeae nas amostras de solo cultivadas com os porta-enxertos Kober e 420-A, respectivamente. Conclui-se que os porta-enxertos estudados apresentam potencial para serem usados em áreas infestadas com esses nematoides das lesões.; The aim of this study was to evaluate the reaction of eight grapevine rootstocks to root-lesion nematodes. Cuttings of the rootstocks Kober...

Ocorrência de Pratylenchus spp. em cafezais do Estado de São Paulo e efeito de Pratylenchus coffeae no crescimento e fotossíntese de Coffea arabica

Kubo, Roberto Kazuhiro
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Tese de Doutorado Formato: ix, 101 f. : il., gráfs.
POR
Relevância na Pesquisa
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Pós-graduação em Agronomia (Proteção de Plantas) - FCA; Amostras de solo e raízes foram coletadas em plantações de café no estado de São Paulo, com o objetivo de determinar a importância e a ocorrência dos nematóides das lesões na cultura do café. A espécie de Pratylenchus mais freqüente foi P. brachyurus (solo: 13,2 %; raízes: 18,3 %), mas geralmente em baixas densidades. O nematóide das lesões do café, P. coffeae, ocorreu em 5,1 % das amostras de raízes, mas em altas densidades e causando mais danos do que a primeira espécie. Outra espécie, P. vulnus, foi encontrada somente em uma localidade. Este é o primeiro relato de P. vulnus em café. Outros fitonematóides identificados nas amostras foram: Xiphinema brevicolle, Xiphinema sp., Paratrichodorus minor, Paratrichodorus sp.,...; Soil and root samples were collected from coffee plantations in the state of São Paulo, in order to determine the occurrence and importance of lesion nematodes in coffee culture. The most frequent species of Pratylenchus was P. brachyurus (soil: 13,2 %; roots: 18,3 %), but generally in low densities. The coffee lesion nematode, P. coffeae, occurred in 5,1 % of root samples...

Response of Peach Seedlings to Infection by the Root Lesion Nematode Pratylenchus penetrans under Controlled Conditions

Potter, J. W.; Dirks, V. A.; Johnson, P. W.; Olthof, T. H. A.; Layne, R. E. C.; McDonnell, M. M.
Fonte: Society of Nematologists Publicador: Society of Nematologists
Tipo: Artigo de Revista Científica
Publicado em /07/1984 EN
Relevância na Pesquisa
66.42%
Twenty-one open pollinated populations of peach rootstock seedlings were evaluated for their response to infection by the root lesion nematode, Pratylenchus penetrans, over a period of 98 days. Nematode-infected peach seedling populations were shorter in plant height and had less shoot weight but more dry root weight than nematode-free controls. Rootstock differences were demonstrated for nematode increase over the 98-day period, and average total numbers of nematodes in soil and roots. Rootstocks were classified into three groups differing in total nematode population levels, ratio of nematode increase, and the number of nematodes per root. The heritable nature of rootstock response to nematodes was evident. Rootstocks showing the lowest response to nematode infection included Tzim Pee Tao, Rutgers Red Leaf, and two progenies of a cross of these two rootstocks.

Strawberry Cultivars Vary in their Resistance to Northern Lesion Nematode

Dale, Adam; Potter, John W.
Fonte: Society of Nematologists Publicador: Society of Nematologists
Tipo: Artigo de Revista Científica
Publicado em /12/1998 EN
Relevância na Pesquisa
46.52%
The genetic diversity of commercial cultivars of strawberry Fragaria x ananassa from various parentages, as expressed by their resistance to the northem lesion nematode Pratylenchus penetrans, was evaluated in nematode-infested field plots for two growing seasons. Data taken for each plant in each season included soil nematode Pi and Pf, end-of-season nematode numbers in each entire root system, and end-of-season fresh and dry top weight and whole root system weight. Resistance was estimated using an index of the nematode load on the plant: Nematode load = {n(root) + (200 × n[soil])}/{root dry weight} where n (root) = number of nematodes in the root, n [soil] = number of nematodes in 50 g of nonfumigated soil, and 200 is a multiplier to convert the soil nematode count to a 10-kg basis. Nineteen strawberry cultivars varied in their resistance to the northern lesion nematode, from a mean load of 382 nematodes/plant for Pajaro to 1,818 nematodes/plant for Veestar. This variability could be related to the original family groupings, with the most resistant cultivars related to Lassen and the least resistant to Sparkle x Valentine.

Efeito de herbicidas sobre a densidade populacional de Pratylenchus brachyurus em cultivares de soja; Effect of herbicides on the population density of Pratylenchus brachyurus on soybean cultivars

Macedo, Leonardo Barros de
Fonte: Universidade Federal de Goiás; Brasil; UFG; Programa de Pós-graduação em Agronomia (EAEA); Escola de Agronomia e Engenharia de Alimentos - EAEA (RG) Publicador: Universidade Federal de Goiás; Brasil; UFG; Programa de Pós-graduação em Agronomia (EAEA); Escola de Agronomia e Engenharia de Alimentos - EAEA (RG)
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
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Soybean (Glycine max L.) is now a major export products from Brazil and one of the main commodities in the world. In the Central West region of Brazil, the main soybean-producing region, the lesion nematode, Pratylenchus brachyurus, has become a major problem for culture can lead to significant losses. Weeds are also a limiting factor for obtaining high yields in soybean, and herbicide application to control it can affect the population of nematodes. This study aimed to evaluate the effect of herbicides, including glyphosate, on the population density of P. brachyurus on soybean conventional and transgenic cultivar. Two experiments were conducted in field conditions and another in a greenhouse in 2010/2011 harvest. The experimental design of the first was completely randomized in factorial arrangement 2x4+2, with four replicates. In greenhouse the design was completely randomized, with the same factorial design and six replications. The factors of the treatments consisted of cultivars, with two levels (BRSGO Iara and M-SOY 8001), and methods of weed control, with four levels (pull-off manual and chemical control with lactofen, chlorimuron-ethyl, and haloxifop-r). Two additional treatments consisted of transgenic cultivar BRS Valiosa RR with manual control of weeds and glyphosate. The assessments for the population of P. brachyurus...

Reação de genótipos de soja ao pratylenchus brachyurus; Reaction of soybean genotypes to Pratylenchus brachyurus

Silva, Adélia Cristina Fernandes
Fonte: Universidade Federal de Goiás; Brasil; UFG; Programa de Pós-graduação em Genetica e Melhoramentode Plantas; Escola de Agronomia e Engenharia de Alimentos - EAEA (RG) Publicador: Universidade Federal de Goiás; Brasil; UFG; Programa de Pós-graduação em Genetica e Melhoramentode Plantas; Escola de Agronomia e Engenharia de Alimentos - EAEA (RG)
Tipo: Tese de Doutorado Formato: application/pdf
POR
Relevância na Pesquisa
46.26%
Soybean is the most important crop in Brazil, which is known for being the second largest producer of the grain. There are several phytosanitary problems that affect the culture and cause losses in production, including plant nematodes. Pratylenchus brachyurus is one of the most widespread nematodes in soybean producing areas of Brazil. The search for genotypes that have resistance to this plant nematode has been widespread, but there is still disagreement regarding the behavior of several brazilian cultivars. Evaluation of soybean cultivars in infested areas has not indicated the existence of materials resistant or tolerant. Thus, this study was to evaluate the reaction to P. brachyurus of six soybean cultivars and eight F1 populations originated from crosses in partial diallel arrangement. We also evaluate the behavior of cultivars exposed to different inoculum concentrations in three planting dates. The first study aimed to evaluate the reaction of cultivars and F1 populations of the plant nematode P. brachyurus. Experiment were conducted in naturally infested field conditions to evaluate the cultivars MT/BR51 (Xingu), BRSGO Caiapônia, MSOY 8360RR, BRS 8560RR, Emgopa 313RR and MSOY 7639RR and another in greenhouse conditions...

Mapping of the root lesion nematode (Pratylenchus neglectus) resistance gene Rlnn1 in wheat

Williams, K.; Taylor, S.; Bogacki, P.; Pallotta, M.; Bariana, H.; Wallwork, H.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em //2002 EN
Relevância na Pesquisa
66.33%
The root lesion nematode, Pratylenchus neglectus, is an economically damaging pathogen of wheat and other crops. The development of P. neglectus-resistant wheat cultivars would be greatly accelerated through the use of molecular markers, as resistance phenotyping is extremely time-consuming. A greenhouse bioassay was developed to identify resistance phenotypes of doubled-haploid populations. Bulked-segregant analysis was used to identify AFLP markers linked to P. neglectus resistance in the wheat cultivar Excalibur. One resistance-linked AFLP marker was mapped close to chromosome 7A RFLP markers in a densely-mapped Cranbrook/Halberd population. One of the chromosome 7A RFLP probes, cdo347, was genotyped in the Tammin/Excalibur population segregating for response to root lesion nematode and showed 8% recombination with the P. neglectus resistance gene Rlnn1. The marker Xcdo347-7A was validated on Excalibur-and Krichauff-derived DH populations segregating for Rlnn1 and showed 14% and 10% recombination, respectively, with Rlnn1 in these populations.; K. Williams, S. Taylor, P. Bogacki, M. Pallotta, H. Bariana and H. Wallwork

Interaction between root lesion nematode, Pratylenchus neglectus, and root-rotting fungi of wheat / by Abdolhossein Taheri.

Taheri, Abdolhossein
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado Formato: 287017 bytes; application/pdf
Publicado em //1996 EN
Relevância na Pesquisa
56.16%
This study concludes that in soils in South Australia where root-rotting fungi and P. neglectus exist together, root disease of wheat is caused by their combined effect. Evidence suggests that P. neglectus not only contributes to this interaction through mechanical wounding of roots, but also causes biochemical and physiological changes in plants, making them more prone to fungal infection.; Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Science, 1996; Bibliography: leaves 307-329.; xvi, 329 leaves, [21] leaves of plates : ill. (chiefly col.), map ; 30 cm.; Title page, contents and abstract only. The complete thesis in print form is available from the University Library.

The role of fungi and the root lesion nematode, Pratylenchus neglectus, in damaging wheat roots in South Australia / Vivien Alison Vanstone.

Vanstone, Vivien Alison
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado Formato: 178146 bytes; application/pdf
Publicado em //1991 EN
Relevância na Pesquisa
76.28%
Pathogens associated with root damage were investigated in the Murray Mallee region of South Australia over the 1987-1989 growing seasons. Occurence of fungal species and the root lesion nematode (Pratylenchus neglectus) was assessed, and related to the appearance and severity of symptoms on the roots. Field experiments were supplemented with innoculation tests in the glasshouse and laboratory.; Thesis (Ph.D.)--University of Adelaide, Depts. of Plant Science and Crop Protection, 1991; Includes bibliographical references (leaves 265-296).; vi, 296 leaves, [14] leaves of plates : ill. (some col.), maps ; 30 cm.; Title page, contents and abstract only. The complete thesis in print form is available from the University Library.

Phytoecdysteroids: a novel defense against plant-parasitic nematodes

Soriano, I.; Riley, I.; Potter, M.; Bowers, W.
Fonte: Kluwer Academic/Plenum Publ Publicador: Kluwer Academic/Plenum Publ
Tipo: Artigo de Revista Científica
Publicado em //2004 EN
Relevância na Pesquisa
46.21%
The phytoecdysteroid, 20-hydroxyecdysone (20E), is a major molting hormone of invertebrates possibly including nematodes. As 20E is inducible in spinach, the defensive role against plant-parasitic nematodes was investigated. The effects of direct application on nematodes was assessed by treating cereal cyst nematode, Heterodera avenae, juveniles with concentrations of 20E from 8.2 × 10⁻⁸ to 5.2 × 10⁻⁵ M before applying to Triticum aestivum growing in sand. H. avenae, Heterodera schachtii (sugarbeet cyst nematode), Meloidogyne javanica (root-knot nematode) and Pratylenchus neglectus (root lesion nematode) were treated with 5.2 × 10⁻⁵ 20E and incubated in moist sand. To test the protective effects of 20E in plants, the latter three nematodes were applied to Spinacia oleracea in which elevated concentrations of 20E had been induced by methyl jasmonate. Abnormal molting, immobility, reduced invasion, impaired development, and death occurred in nematodes exposed to 20E either directly at concentration above 4.2 × 10⁻⁷ M or in plants. Phytoecdysteroid was found to protect spinach from plant-parasitic nematodes and may confer a mechanism for nematode resistance.; The original publication can be found at www.springerlink.com

Assessing the importance of subsoil constraints to yield of wheat and its implications for yield improvement

McDonald, G.; Taylor, J.; Verbyla, A.; Kuchel, H.
Fonte: CSIRO Publishing Publicador: CSIRO Publishing
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
66.3%
Many of the soils in the Australian cereal belt have subsoils with chemical and physical properties that restrict root growth, which limits water use and yield. On alkaline sodic soils salinity, high pH, high available boron (B), deficiencies of zinc (Zn) and manganese (Mn) and high soil strength occur commonly and aluminium (Al) toxicity restricts root growth on acid soils. While the effects of individual subsoil constraints have been studied there is some debate about the relative importance to yield of the different soil stresses across the region. To address this issue yield variation among a set of 52 varieties of bread wheat was analysed using yield data from 233 trials conducted over 12 years. The trials were conducted in all mainland States but the majority were in South Australia and Western Australia. Each variety was characterised for its response to high B, high pH, Al toxicity, salinity, deficiencies in Zn and Mn and resistance to root lesion nematode (Pratylenchus neglectus), root growth through strong soil, seminal root angle, carbon isotope discrimination (CID) and maturity. This data was then used to examine the contribution of each trait to the genetic variation in yield at each of the 233 trials. The contribution of a specific trait to the genetic variation in yield at each site was used to infer the importance of a particular constraint to yield at that site. Of the traits linked to soil constraints...

Genetic and biological characterisation of resistance to root lesion nematode Pratylenchus thornei in wheat.

Linsell, Katherine Joanne
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2013
Relevância na Pesquisa
86.57%
Root lesion nematodes of the genus Pratylenchus feed and reproduce in the root cortex of many plant species, including wheat. Migration through root tissue causes extensive root damage, and in turn severe reductions in growth and yield. In Australia, one of the most prevalent and widespread species affecting wheat is Pratylenchus thornei. Due to the wide host range of Pratylenchus spp. and the restrictions and inefficiency of chemical pesticides, the development of resistant cultivars has become increasingly important. Despite the identification and investigation of several resistance sources and resistance quantitative trait loci (QTL), no P. thornei resistance has been integrated into commercial cultivars. In addition, prior to this study, the biological resistance mechanisms of wheat against P. thornei were not well characterised. The identification of novel sources of genetic resistance in wheat and understanding of the biological mechanisms will allow effective combinations of genes either to be used alternatively or pyramided to generate effective and stable Pratylenchus resistance. The major objectives of the study were to identify genetic loci associated with P. thornei resistance and to investigate the associated biological mechanisms in a double haploid wheat population developed from a cross between the synthetically derived Sokoll and the Australian adapted Krichauff parental lines. The resistance to P. thornei observed in the Sokoll x Krichauff wheat population is complex and under the control of several loci which suppress all nematode developmental stages. The four main components of the root invasion process by Pratylenchus: root attraction...

Genetic mapping and marker development for resistance of wheat against the root lesion nematode Pratylenchus neglectus

Jayatilake, D.; Tucker, E.; Bariana, H.; Kuchel, H.; Edwards, J.; McKay, A.; Chalmers, K.; Mather, D.
Fonte: BioMed Central Ltd. Publicador: BioMed Central Ltd.
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
Relevância na Pesquisa
96.33%
BACKGROUND The Rlnn1 locus, which resides on chromosome 7A of bread wheat (Triticum aestivum L.) confers moderate resistance against the root lesion nematode Pratylenchus neglectus. Prior to this research, the exact linkage relationships of Rlnn1 with other loci on chromosome 7A were not clear and there were no simple codominant markers available for selection of Rlnn1 in wheat breeding. The objectives of the research reported here were to (1) develop an improved genetic map of the Rlnn1 region of chromosome 7A and (2) develop molecular markers that could be used in marker-assisted selection to improve resistance of wheat against P. neglectus. RESULTS A large-effect quantitative trait locus (QTL) for resistance against P. neglectus was genetically mapped using a population of Excalibur/Kukri doubled haploid lines. This QTL coincides in position with the rust resistance gene(s) Lr20/Sr15, the phytoene synthase gene Psy-A1 and 10 molecular markers, including five new markers designed using wheat-rice comparative genomics and wheat expressed sequence tags. Two of the new markers are suitable for use as molecular diagnostic tools to distinguish plants that carry Rlnn1 and Lr20/Sr15 from those that do not carry these resistance genes. CONCLUSIONS The genomic location of Rlnn1 was confirmed to be in the terminal region of the long arm of chromosome 7A. Molecular markers were developed that provide simple alternatives to costly phenotypic assessment of resistance against P. neglectus in wheat breeding. In Excalibur...

Genetic analysis of tolerance to the root lesion nematode Pratylenchus neglectus in the legume Medicago littoralis

Oldach, K.H.; Peck, D.M.; Nair, R.M.; Sokolova, M.; Harris, J.; Bogacki, P.; Ballard, R.
Fonte: Biomed Central Publicador: Biomed Central
Tipo: Artigo de Revista Científica
Publicado em //2014 EN
Relevância na Pesquisa
76.34%
BACKGROUND: The nematode Pratylenchus neglectus has a wide host range and is able to feed on the root systems of cereals, oilseeds, grain and pasture legumes. Under the Mediterranean low rainfall environments of Australia, annual Medicago pasture legumes are used in rotation with cereals to fix atmospheric nitrogen and improve soil parameters. Considerable efforts are being made in breeding programs to improve resistance and tolerance to Pratylenchus neglectus in the major crops wheat and barley, which makes it vital to develop appropriate selection tools in medics. RESULTS: A strong source of tolerance to root damage by the root lesion nematode (RLN) Pratylenchus neglectus had previously been identified in line RH-1 (strand medic, M. littoralis). Using RH-1, we have developed a single seed descent (SSD) population of 138 lines by crossing it to the intolerant cultivar Herald. After inoculation, RLN-associated root damage clearly segregated in the population. Genetic analysis was performed by constructing a genetic map using simple sequence repeat (SSR) and gene-based SNP markers. A highly significant quantitative trait locus (QTL), QPnTolMl.1, was identified explaining 49% of the phenotypic variation in the SSD population. All SSRs and gene-based markers in the QTL region were derived from chromosome 1 of the sequenced genome of the closely related species M. truncatula. Gene-based markers were validated in advanced breeding lines derived from the RH-1 parent and also a second RLN tolerance source...

Plant-Parasitic nematodes infecting grapevine in southern Spain and susceptible reaction to root-knot nematodes of rootstocks reported as moderately resistant

Téliz, D.; Landa, Blanca B.; Rapoport, Hava F.; Perez Camacho, F.; Jiménez-Díaz, Rafael M.; Castillo, Pablo
Fonte: American Phytopathological Society Publicador: American Phytopathological Society
Tipo: Artículo Formato: 4085 bytes; image/gif
ENG
Relevância na Pesquisa
46.2%
Incidence and nematode population densities of plant-parasitic nematodes were determined in 64 samples of soil and grapevine roots collected from commercial vineyards in southern Spain between October 2003 and May 2005. In addition, a histopathological study was done of root-stock roots naturally infected by root-knot nematodes (Meloidogyne spp.). Nematodes infecting the rootstocks were identified according to conventional procedures, and the Meloidogyne spp. were furthermore identified by sequence characterized amplified region-polymerase chain reaction (SCAR-PCR) and isozyme esterase analyses. The most important plant-parasitic nematodes detected, in order of decreasing frequency of total soil infestation and root infection (percentage of samples), were Mesocriconema xenoplax (34.4%), Meloidogyne incognita (26.6%), Meloidogyne javanica (14.1%), Xiphinema index (12.5%), Xiphinema italiae (10.9%), Pratylenchus vulnus (6.3%), and Meloidogyne arenaria (1.6%). No disease symptoms were observed on aboveground plant parts of the infected grapevines, except for plants in some fields where soil was infested with the virus-vector nematodes X. index and X. italiae. Those grapevines showed a yellow mosaic pattern in leaves early in the growing season and the internode shortening characteristic of infections by Grapevine fanleaf virus. Rootstocks infected by root-knot nematodes (Meloidogyne spp.) showed distorted feeder roots and large- to moderate-sized root galls...

Identification of Pratylenchus thornei, the cereal and legume root-lesion nematode, based on SCAR-PCR and satellite DNA

Carrasco-Ballesteros, S.; Castillo, Pablo; Adams, B. J.; Pérez-Artés, Encarnación
Fonte: Springer Publicador: Springer
Tipo: Artículo Formato: 4085 bytes; image/gif
ENG
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Two different molecular tools for the diagnosis of the cereal and legume root-lesion nematode Pratylenchus thornei were developed. A randomly amplified DNA (RAPD) fragment specific to P. thornei was identified. After sequencing the fragment, longer primers were designed that complement the terminal sequences of the RAPD fragment, and this pair of specific primers was used to amplify the sequence-characterized amplified region (SCAR). Using the developed pair of SCAR primers, the SCAR fragment specific to P. thornei was easily amplified with DNA extracts obtained from different life stages of the nematode. The described SCARPCR- based assay has the potential to be optimized for routine practical diagnostic tests. In addition, the use of a species-specific satellite DNA sequence to distinguish P. thornei from other Pratylenchus spp. is discussed.; This research was supported by grant AGF98-0878 from Comisión Interministerial de Ciencia y Tecnología (CICYT) of Spain; Peer reviewed

Parasitism of the root-lesion nematode Pratylenchus thornei on chickpea

Castillo, Pablo; Jiménez-Díaz, Rafael M.; Gómez Barcina, Antonio; Vovlas, Nicola
Fonte: Blackwell Publishing Publicador: Blackwell Publishing
Tipo: Artículo Formato: 449823 bytes; application/pdf
ENG
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Pratylenchus thornei-chickpea interactions were investigated under controlled and fluctuating environmental conditions in the growth chamber, greenhouse and shadehouse. Under controlled conditions. P. thornei infected chickpea hnes 12071/10054 and P2245 and cultivars Andoum 1, JG62 and UC 27. Line P 2245 and cv. JG 62 were the most susceptible genotypes on the basis of root damage and nematode reproduction, but nematode infection did not significantly reduce root and shoot weights. Cultivars Andoum 1 and UC27 and line 12071/10054 showed the least root damage and nematode reproduction. Inoculation of cv. Andoum 1 with 2500, 5000 or lOOOO nematodes per plant in pots did not affect shoot weight, regardless ofthe conditions of water stress ofthe plants. However, root weight was significantly reduced by nematode infection in plants grown under water stress and fluctuating temperature conditions in the greenhouse, but was not affected by any other treatment. The nematode reproduction index was not affected by soil water content under shadehouse conditions, but was greater on plants watered to soil water-holding capacity than in water-stressed plants under greenhouse conditions. For both environments, the nematode reproduction index decreased when inoculum density was greater than 5000 nematodes per plant.; This research was supported by grant AGF92- 0910-CO2-01 from Comision Interministerial de Ciencia y Technologia (CICYT)...