Showing papers on "Heterodera avenae published in 1997"
TL;DR: The Cre3 gene confers a high level of resistance to the root endoparasitic nematode Heterodera avenae in wheat and two related gene sequences have been analysed at the Cre3 locus, which appears to be a pseudogene with a frame shift caused by a deletion event.
Abstract: The Cre3 gene confers a high level of resistance to the root endoparasitic nematode Heterodera avenae in wheat. A DNA marker cosegregating with H. avenae resistance was used as an entry point for m...
161 citations
TL;DR: Analysis of a further seven sources of CCN resistance in the form of near-isogenic lines (NILs) indicates that all available sources of resistance to the Australian pathotype ofCCN in barley represent the Ha 2 locus.
Abstract: The cereal cyst nematode (CCN), Heterodera avenae Woll., is an economically damaging pest of barley in many of the world’s cereal-growing areas. The development of CCN-resistant cultivars may be accelerated through the use of molecular markers. A number of resistance genes against the pest are well known; one of them, the single dominant Ha 2 resistance gene, has been shown to be effective against the Australian pathotype and maps to chromosome 2 of barley. Segregation analysis identified two restriction fragment length polymorphism (RFLP) markers flanking the resistance gene in two doubled-haploid populations of barley. AWBMA 21 and MWG 694 mapped 4.1 and 6.1 cM respectively from the Ha 2 locus in the Chebec×Harrington cross and 4.0 and 9.2 cM respectively in the Clipper×Sahara cross. Analysis of a further seven sources of CCN resistance in the form of near-isogenic lines (NILs) indicates that all available sources of resistance to the Australian pathotype of CCN in barley represent the Ha 2 locus.
76 citations
TL;DR: The inferred phylogenetic relationships of species in the CCN complex are in agreement with their morphological characterization, and restriction sites have revealed a mixture of the species H. latipons and H. avenae, and possible infraspecific variation in Heterodera avenae.
Abstract: This study examined the restriction polymorphism (RFLP) of the nuclear ribosomal DNA in Heterodera avenae, H. filipjevi, H. mani, H. latipons, and the taxonomically unclear Gotland strain in order ...
63 citations
TL;DR: The results indicate that several resistances to P. thornei are present in Ae.
Abstract: Root-lesion nematode (Pratylenchus thornei Sher and Allen) causes substantial loss in yield of wheat in eastern Australia. Central Asian accessions of Aegilops tauschii Coss. were tested to find new sources of resistance to P. thornei for use in wheat-breeding programs. Ae. tauschii (2n = 14, DD genome) is one of the wild progenitors of wheat, Triticum aestivum L. (2n = 42, AABBDD genomes). Resistance was determined by nematode reproduction in the plant roots during 16 weeks of growth in pots in a glasshouse. Thirty-nine of 244 accessions of Ae. tauschii tested in 2 replicated experiments had lower numbers of nematodes than GS50a, a partially resistant line of wheat used as a resistance standard. Resistance to P. thornei was present in accessions of most taxonomic groups within Ae. tauschii, i.e. Ae. tauschii subsp. strangulata (Eig) Tzvel., and Ae. tauschii subsp. tauschii var. typica L. and var. meyeri (Griseb.) Tzvel. Resistance was most common in subsp. strangulata with 20 out of 40 strangulata accessions in the resistant group and none in a highly susceptible group of 43 accessions. Accessions of var. meyeri with the Cre3 gene for effective resistance to cereal cyst nematode (Heterodera avenae Woll.) were also resistant to P. thornei. The results indicate that several resistances to P. thornei are present in Ae. tauschii subspecies and varieties, which could be introgressed into cultivated wheat to help control P. thornei and increase farm profits.
48 citations
TL;DR: Barley lectin and wheat germ agglutinin (WGA) accumulated in the roots of both resistant and susceptible cultivars of barley and wheat following invasion by second-stage juveniles (J2) of the cereal cyst nematode Heterodera avenaeWoll.
18 citations
TL;DR: A protein that cross-reacts to a wheat-germ agglutinin antibody was induced in oat roots following the invasion of second-stage juveniles of the cereal cyst nematode Heterodera avenae, and JA is suggested to be involved in signal transduction after pathogen invasion of the plant.
Abstract: A protein that cross-reacts to a wheat-germ agglutinin antibody was induced in oat roots following the invasion of second-stage juveniles (J2) of the cereal cyst nematode Heterodera avenae. This protein, designated ASP45, was acid soluble, and its molecular mass was about 45 kDa on a sodium dodecyl sulfate-polyacrylamide gel. ASP45 was induced in both compatible and incompatible interactions between the nematode and the plant, and also in roots by exposure to jasmonic acid (JA) or methyl jasmonate. However, ASP45 was not induced by elicitors of pathogenesis-related proteins, abscisic acid, or wounding. Lipoxygenase activity, which is involved in JA synthesis, was higher in nematode-infected and JA-treated roots than in their noninfected, untreated counterparts. Inhibition of lipoxygenase activity in roots abolished ASP45 induction in the nematode-infected roots. Amino acid sequences similar to that of ASP45 were found in chitinases of poplar tree and Arabidopsis, even though ASP45 showed no chitinase acti...
16 citations
Journal Article•
TL;DR: Protein changes were found at an early stage of infection in barley and wheat roots infected with H. avenae, but no difference was found between resistant and susceptible cultivars, and a few changes in intercellular leaf proteins were recorded in resistant cultivars.
Abstract: Changes in root- and leaf-soluble proteins were investigated in tomato after invasion by the root-knot nematode Meloidogyne javanica, or in barley and wheat after invasion by the cereal cyst nematode Heterodera avenae. Infection of susceptible tomato plants by M. javanica did not cause any change in the soluble-protein composition of leaves or roots compared with uninoculated plants at an early infection stage. No pathogenesis-related proteins (chitinase, glucanase, or P-14) were induced in the leaf apoplast. Changes in leaf proteins were not observed after invasion of wheat cultivars by H. avenae, whereas, in barley, a few changes in intercellular leaf proteins were recorded in resistant cultivars. These changes, however, were not the same among different H. avenae-resistant cultivars. Protein changes were found at an early stage of infection in barley and wheat roots infected with H. avenae, but no difference was found between resistant and susceptible cultivars. Key words: barley, cereal cyst nematode, chitinase, glucanase, Heterodera avenae, Hordeum vulgate, Lycopersicon esculentum, Meloidogyne javanica, nematode, pathogenesis-related proteins, root-knot nematode, tomato, Triticum aestivum, wheat.
14 citations
TL;DR: Breeding wheat for resistance to Heterodera avenae in southern Australia has been in progress for nearly 30 years and recently a number of resistant varieties have been released.
Abstract: Breeding wheat for resistance to Heterodera avenae in southern Australia has been in progress for nearly 30 years and recently a number of resistant varieties have been released. Early breeding work was hampered by three factors: • a lack of appreciation of the role and extent of the problem, • inaccurate, slow screening methods, ultimately being replaced by the 'tube' test and soon by linked molecular markers, • inappropriate breeding strategies, so that varietal releases have taken place only when the breeding has been fully integrated into the main programs. The experiences in southern Australia will be relevant to many other areas in the world where H. avenae is the major pest.
11 citations
15 Jun 1997
TL;DR: A survey to determine the frequency and abundance of plant parasitic nematodes in unirrigated fields of Alhama region (south-eastern Spain), mainly under wheat and barley, but also food and forage legumes and olive trees, found Heterodera avenae was the most widespread species.
Abstract: A survey was conducted to determine the frequency and abundance of plant parasitic nematodes in unirrigated fields of Alhama region (south-eastern Spain), mainly under wheat and barley, but also food and forage legumes and olive trees. Seventy-seven fields were sampled from a total area of 38,575 ha. Heterodera avenae was the most widespread species in the area, followed by Merlinius brevidens, Pratylenchus neglectus, Pratylenchus thornei, Meloidogyne artiellia and Zygotylenchus guevarai. Twenty-three other species of plant parasitic nematodes were found. Morphometrics of Paratrophurus acristylus, Paratylenchus sheri, P. nanus and P. similes from Southern Spain are provided. Paratylenchus israeliensis is proposed as a new junior synonym of P. sheri.
10 citations
TL;DR: A double antibody sandwich enzyme linked immunosorbent assay (DAS-ELISA) was the better ELISA format used to identify and quantify the CCN population from the processed soil samples containing up to 20% of organic matter.
Abstract: Monoclonal antibodies (MAbs) and polyclonal antibodies (PCs) were produced to antigens of an Australian population of cereal cyst nematode (CCN), Heterodera avenae. MAb IACR CCNj-49.2 recognised an antigen with a molecular weight of approximately 200 kDa, which was immunolocalised apparently in granules in the nematode gut. A procedure to extract CCN antigens from soil samples, under laboratory conditions was devised, and 50 g samples of soil containing 5 CCN cysts were processed by two sets of flotation techniques to recover the nematodes. Milling using Ballotini glass beads was then used to release the antigens from the CCN cysts recovered in the float. A double antibody sandwich enzyme linked immunosorbent assay (DAS-ELISA) was the better ELISA format used to identify and quantify the CCN population from the processed soil samples containing up to 20% of organic matter. The threshold limit of detection was estimated by serial dilutions of the soil extracts. It was approximately equivalent to 0.5 eggs or 3.6 eggs per g of soil in a DAS-ELISA, when using respectively the PC or the MAb as the trapping antibody. The assay could be made more sensitive in soils with lower contents of organic matter.
8 citations
Journal Article•
TL;DR: Although plant leaf extracts revealed non-significant larval hatch, yet plants, viz., Euphorbia hirta and Oxalis corniculata effectively reduced hatch in H. cajani, two dilutions of leaf extracts greatly enhanced/retarded larval emergence.
Abstract: Besides toxicity to the second stage larvae of cyst nematodes (Heterodera avenae and H cajani), larval emergence from cysts was also influenced by some plant leaf extracts Two dilutions of leaf extracts, ie, 1:5 and 1:20 at 3, 6 and 9 days intervals greatly enhanced/retarded larval emergence Although plant leaf extracts revealed non-significant larval hatch, yet plants, viz, Euphorbia hirta and Oxalis corniculata effectively reduced hatch in H avenue and Solanum xanthocarpum in H cajani