Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Fine mapping of the gene Rvi18 (V25) for broad-spectrum resistance to apple scab, and development of a linked SSR marker suitable for marker-assisted breeding
    Soriano, J.M. ; Madduri, M. ; Schaart, J. ; Burgh, A.M. van der; Kaauwen, M.P.W. van; Tomic, L. ; Groenwold, R. ; Velasco, R. ; Weg, W.E. van de; Schouten, H.J. - \ 2014
    Molecular Breeding 34 (2014)4. - ISSN 1380-3743 - p. 2021 - 2032.
    malus-x-domestica - venturia-inaequalis - microsatellite markers - cisgenic plants - genome - borkh. - receptors - lectins - race
    Apple scab, caused by the fungal pathogen Venturia inaequalis, is one of the most devastating diseases for the apple growing industry in temperate zones with humid springs and summers. Breeding programs around the world have identified several sources of resistance, of which the Rvi6 (Vf) gene from Malus floribunda 821 has been the most widely used. The appearance of Rvi6-virulent strains of V. inaequalis in several European countries have underlined the necessity of pyramiding different effective resistance genes for durably resistant cultivars. Here we report the mapping of the new apple scab resistance gene Rvi18 (V25) from the selection 1980-015-025 of the apple breeding program at Wageningen University and Research Centre, The Netherlands. This gene was fine mapped on the proximal part of LG11 to a region of 34 Kb in the apple genome sequence of ‘Golden Delicious’, using 894 progeny plants, and SSR, DArT, AFLP, and SNP markers. One gene on the ‘Golden Delicious’ reference genome was identified as the potential susceptibility allele of the resistance gene. Moreover, an SSR marker has been developed of which one of its amplicons sizes is highly specific for Rvi18, thus facilitating the directed pyramiding of resistance genes through marker assisted breeding.
    The domestication and evolutionary ecology of apples
    Cornille, A. ; Giraud, T. ; Smulders, M.J.M. ; Roldán-Ruiz, I. ; Gladieux, P. - \ 2014
    Trends in Genetics 30 (2014)2. - ISSN 0168-9525 - p. 57 - 65.
    wild malus-orientalis - genetic-structure - population-structure - venturia-inaequalis - crop domestication - cultivated apple - fruit - sylvestris - markers - mill.
    The cultivated apple is a major fruit crop in temperate zones. Its wild relatives, distributed across temperate Eurasia and growing in diverse habitats, represent potentially useful sources of diversity for apple breeding. We review here the most recent findings on the genetics and ecology of apple domestication and its impact on wild apples. Genetic analyses have revealed a Central Asian origin for cultivated apple, together with an unexpectedly large secondary contribution from the European crabapple. Wild apple species display strong population structures and high levels of introgression from domesticated apple, and this may threaten their genetic integrity. Recent research has revealed a major role of hybridization in the domestication of the cultivated apple and has highlighted the value of apple as an ideal model for unraveling adaptive diversification processes in perennial fruit crops. We discuss the implications of this knowledge for apple breeding and for the conservation of wild apples.
    Cloning and functional characterization of the Rvi15 (Vr2) gene for apple scab resistance
    Schouten, H.J. ; Brinkhuis, J. ; Burgh, S. van der; Schaart, J. ; Groenwold, R. ; Broggini, G.A.L. ; Gessler, C. - \ 2014
    Tree Genetics and Genomes 10 (2014)2. - ISSN 1614-2942 - p. 251 - 260.
    malus x domestica - venturia-inaequalis - cladosporium-fulvum - cisgenic plants - plasma-membrane - vf gene - tomato - locus - proteins - pathogen
    Apple scab, caused by Venturia inaequalis, is a serious disease of apple. Previously, the scab resistance Rvi15 (Vr2) from the accession GMAL 2473 was genetically mapped, and three candidate resistance genes were identified. Here, we report the cloning and functional characterization of these three genes, named Vr2-A, Vr2-B, and Vr2-C. Each gene was cloned with its native promoter, terminator and introns, and inserted into the susceptible apple cultivar ‘Gala’. Inoculation of the plants containing Vr2-A and Vr2-B induced no resistance symptoms, but abundant sporulation. However, inoculation of the plants harboring Vr2-C showed a hypersensitive response with clear pinpoint pits, and no or very little sporulation. We conclude that Vr2-C is the Rvi15 (Vr2) gene. This gene belongs to the Toll and mammalian interleukin-1 receptor protein nucleotide-binding site leucine-rich repeat structure resistance gene family. The proteins of this gene family reside in the cytoplasm, whereas V. inaequalis develops in the apoplast, between the epidermis and cuticle, without making haustoria. The spatial separation of the recognizing resistance protein and the pathogen is discussed. This is the second cloned gene for apple scab resistance, and out of these two the only one leading to a symplastic protein.
    The role of Schmidt 'Antonovka' in apple scab resistance breeding
    Bus, V.G.M. ; Weg, W.E. van de; Peil, A. ; Dunemann, F. ; Zini, E. ; Laurens, F.N.D. ; Blazek, J. ; Hanke, V. ; Forsline, P.L. - \ 2012
    Tree Genetics and Genomes 8 (2012)4. - ISSN 1614-2942 - p. 627 - 642.
    venturia-inaequalis - dresden-pillnitz - molecular characterization - candidate genes - broad-spectrum - rapd markers - race 6 - malus - cultivars - pathogen
    'Antonovka' has long been recognised as a major source of scab (Venturia inaequalis) resistance useful for apple breeding worldwide. Both major gene resistances in the form of the Rvi10 and Rvi17 and quantitative resistance, collectively identified as VA, have been identified in different accessions of 'Antonovka'. Most of the 'Antonovka' scab resistance used in apple-breeding programmes around the world can be traced back to Schmidt 'Antonovka' and predominantly its B VIII progenies 33,25 (PI 172623), 34,6 (PI 172633), 33,8 (PI 172612) and 34,5 (PI 172632). Using genetic profile reconstruction, we have identified "common 'Antonovka' " as the progenitor of the B VIII family, which is consistent with it having been a commercial cultivar in Poland and the single source of scab resistance used by Dr. Martin Schmidt. The major 'Antonovka' scab resistance genes mapped to date are located either very close to Rvi6, or about 20-25 cM above it, but their identities need further elucidation. The presence of the 139 bp allele of the CH-Vf1 microsatellite marker known to be associated with Rvi17 (Va1) in most of the 'Antonovka' germplasm used in breeding suggests that it plays a central role in the resistance. The nature and the genetic relationships of the scab resistance in these accessions as well as a number of apple cultivars derived from 'Antonovka', such as, 'Freedom', 'Burgundy' and 'Angold', are discussed. The parentage of 'Reglindis' is unclear, but the cultivar commercialised as 'Reglindis' was confirmed to be an Rvi6 cultivar.
    Towards genomic selection in apple (Malus x domestica Borkh.) breeding programmes: Prospects, challenges and strategies
    Kumar, S. ; Bink, M.C.A.M. ; Volz, R.K. ; Bus, V.G.M. ; Chagne, D. - \ 2012
    Tree Genetics and Genomes 8 (2012)1. - ISSN 1614-2942 - p. 1 - 14.
    marker-assisted selection - mildew-resistance gene - linear unbiased prediction - quantitative trait loci - fire blight resistance - fruit-quality traits - linkage group 3 - powdery-mildew - venturia-inaequalis - molecular markers
    The apple genome sequence and the availability of high-throughput genotyping technologies have initiated a new era where SNP markers are abundant across the whole genome. Genomic selection (GS) is a statistical approach that utilizes all available genome-wide markers simultaneously to estimate breeding values or total genetic values. For breeding programmes, GS is a promising alternative to the traditional marker-assisted selection for manipulating complex polygenic traits often controlled by many small-effect genes. Various factors, such as genetic architecture of selection traits, population size and structure, genetic evaluation systems, density of SNP markers and extent of linkage disequilibrium, have been shown to be the key drivers of the accuracy of GS. In this paper, we provide an overview of the status of these aspects in current apple-breeding programmes. Strategies for GS for fruit quality and disease resistance are discussed, and an update on an empirical genomic selection study in a New Zealand apple-breeding programme is provided, along with a foresight of expected accuracy from such selection.
    Structure, dynamics and domain organization of the repeat protein Cin1 from the apple scab fungus
    Mesarich, C.H. ; Schmitz, M. ; Tremouilhac, P. ; McGillivray, D.J. ; Templeton, M.D. ; Dingley, A.J. - \ 2012
    Biochimica et Biophysica Acta. Proteins & Proteomics 1824 (2012)10. - ISSN 1570-9639 - p. 1118 - 1128.
    model-free approach - magnetic-resonance relaxation - nmr structure determination - ray solution scattering - torsion angle dynamics - cell-wall protein - venturia-inaequalis - zinc-fingers - helicobacter-pylori - backbone dynamics
    Venturia inaequalis is a hemi-biotrophic fungus that causes scab disease of apple. A recently-identified gene from this fungus, cin1 (cellophane-induced 1), is up-regulated over 1000-fold in planta and considerably on cellophane membranes, and encodes a cysteine-rich secreted protein of 523 residues with eight imperfect tandem repeats of ~ 60 amino acids. The Cin1 sequence has no homology to known proteins and appears to be genus-specific; however, Cin1 repeats and other repeat domains may be structurally similar. An NMR-derived structure of the first two repeat domains of Cin1 (Cin1-D1D2) and a low-resolution model of the full-length protein (Cin1-FL) using SAXS data were determined. The structure of Cin1-D1D2 reveals that each domain comprises a core helix–loop–helix (HLH) motif as part of a three-helix bundle, and is stabilized by two intra-domain disulfide bonds. Cin1-D1D2 adopts a unique protein fold as DALI and PDBeFOLD analysis identified no structural homology. A 15N backbone NMR dynamic analysis of Cin1-D1D2 showed that a short stretch of the inter-domain linker has large amplitude motions that give rise to reciprocal domain–domain mobility. This observation was supported by SAXS data modeling, where the scattering length density envelope remains thick at the domain–domain boundary, indicative of inter-domain dynamics. Cin1-FL SAXS data models a loosely-packed arrangement of domains, rather than the canonical parallel packing of adjacent HLH repeats observed in a-solenoid repeat proteins. Together, these data suggest that the repeat domains of Cin1 display a “beads-on-a-string” organization with inherent inter-domain flexibility that is likely to facilitate interactions with target ligands.
    Diversity arrays technology (DArT) markers in apple for genetic linkage maps
    Schouten, H.J. ; Weg, W.E. van de; Carling, J. ; Khan, S.A. ; McKay, S.J. ; Kaauwen, M.P.W. van - \ 2012
    Molecular Breeding 29 (2012)3. - ISSN 1380-3743 - p. 645 - 660.
    x-domestica borkh. - quantitative trait loci - fire-blight resistance - malus-pumila mill. - venturia-inaequalis - ssr markers - assisted selection - scab resistance - wild relatives - consensus map
    Diversity Arrays Technology (DArT) provides a high-throughput whole-genome genotyping platform for the detection and scoring of hundreds of polymorphic loci without any need for prior sequence information. The work presented here details the development and performance of a DArT genotyping array for apple. This is the first paper on DArT in horticultural trees. Genetic mapping of DArT markers in two mapping populations and their integration with other marker types showed that DArT is a powerful high-throughput method for obtaining accurate and reproducible marker data, despite the low cost per data point. This method appears to be suitable for aligning the genetic maps of different segregating populations. The standard complexity reduction method, based on the methylation-sensitive PstI restriction enzyme, resulted in a high frequency of markers, although there was 52-54% redundancy due to the repeated sampling of highly similar sequences. Sequencing of the marker clones showed that they are significantly enriched for low-copy, genic regions. The genome coverage using the standard method was 55-76%. For improved genome coverage, an alternative complexity reduction method was examined, which resulted in less redundancy and additional segregating markers. The DArT markers proved to be of high quality and were very suitable for genetic mapping at low cost for the apple, providing moderate genome coverage.
    Functional analysis and expression of HcrVf1 and HcrVf2 for development of scab resistant cisgenic and intragenic apples
    Joshi, S.G. ; Schaart, J. ; Groenwold, R. ; Jacobsen, E. ; Schouten, H.J. ; Krens, F.A. - \ 2011
    Plant Molecular Biology 75 (2011)6. - ISSN 0167-4412 - p. 579 - 591.
    receptor-like genes - real-time pcr - venturia-inaequalis - vf gene - plants - sequences - agrobacterium - promoters - linkage - cluster
    Apple scab resistance genes, HcrVf1 and HcrVf2, were isolated including their native promoter, coding and terminator sequences. Two fragment lengths (short and long) of the native gene promoters and the strong apple rubisco gene promoter (PMdRbc) were used for both HcrVf genes to test their effect on expression and phenotype. The scab susceptible cultivar ‘Gala’ was used for plant transformations and after selection of transformants, they were micrografted onto apple seedling rootstocks for scab disease tests. Apple transformants were also tested for HcrVf expression by quantitative RT-PCR (qRTPCR). For HcrVf1 the long native promoter gave significantly higher expression that the short one; in case of HcrVf2 the difference between the two was not significant. The apple rubisco gene promoter proved to give the highest expression of both HcrVf1 and HcrVf2. The top four expanding leaves were used initially for inoculation with monoconidial isolate EU-B05 which belongs to race 1 of V. inaequalis. Later six other V. inaequalis isolates were used to study the resistance spectra of the individual HcrVf genes. The scab disease assays showed that HcrVf1 did not give resistance against any of the isolates tested regardless of the expression level. The HcrVf2 gene appeared to be the only functional gene for resistance against Vf avirulent isolates of V. inaequalis. HcrVf2 did not provide any resistance to Vf virulent strains, even not in case of overexpression. In conclusion, transformants carrying the apple-derived HcrVf2 gene in a cisgenic as well as in an intragenic configuration were able to reach scab resistance levels comparable to the Vf resistant control cultivar obtained by classical breeding, cv. ‘Santana’.
    Performance and long-term stability of the barley hordothionin gene in multiple transgenic apple lines
    Krens, F.A. ; Schaart, J.G. ; Groenwold, R. ; Walraven, A.E.J. ; Hesselink, T. ; Thissen, J.T.N.M. - \ 2011
    Transgenic Research 20 (2011)5. - ISSN 0962-8819 - p. 1113 - 1123.
    receptor-like genes - scab resistance - venturia-inaequalis - expression - thionins - vf - transformation - agrobacterium - plants - wheat
    Introduction of sustainable scab resistance in elite apple cultivars is of high importance for apple cultivation when aiming at reducing the use of chemical crop protectants. Genetic modification (GM) allows the rapid introduction of resistance genes directly into high quality apple cultivars. Resistance genes can be derived from apple itself but genetic modification also opens up the possibility to use other, non-host resistance genes. A prerequisite for application is the long-term performance and stability of the gene annex trait in the field. For this study, we produced and selected a series of transgenic apple lines of two cultivars, i.e. ‘Elstar’ and ‘Gala’ in which the barley hordothionin gene (hth) was introduced. After multiplication, the GM hth-lines, non-GM susceptible and resistant controls and GM non-hth controls were planted in a random block design in a field trial in 40 replicates. Scab resistance was monitored after artificial inoculation (first year) and after natural infection (subsequent years). After the trial period, the level of expression of the hth gene was checked by quantitative RT-PCR. Four of the six GM hth apple lines proved to be significantly less susceptible to apple scab and this trait was found to be stable for the entire 4-year period. Hth expression at the mRNA level was also stable
    Survival of pathogens of Brussels sprouts (Brassica oleracea Gemifera group) in crop residues
    Köhl, J. ; Vlaswinkel, M.E.T. ; Groenenboom-de Haas, B.H. ; Kastelein, P. ; Hoof, R.A. van; Wolf, J.M. van der; Krijger, M.C. - \ 2011
    Plant Pathology 60 (2011)4. - ISSN 0032-0862 - p. 661 - 670.
    alternaria-brassicae - mycosphaerella-brassicicola - venturia-inaequalis - primary inoculum - oilseed rape - leaf-litter - debris - soil - management - ascospores
    Mycosphaerella brassicicola (ringspot), Alternaria brassicicola and A. brassicae (dark leaf spot) and Xanthomonas campestris pv. campestris (black spot) can infect leaves of Brussels sprouts resulting in yield losses. Infections of outer leaves of sprouts cause severe losses in quality. Crop residues can be a major primary inoculum source of the pathogens. Their population dynamics were followed in residues of leaves and stalks of crops of Brussels sprouts during 24 months using real-time PCR assays. Leaf residues on the soil surface or buried in soil decomposed within 4 months. However, residues of stalks were present in the field after 24 months. In such residues, M. brassicicola populations increased during the first 2 months, but decreased thereafter and the pathogen was found only occasionally in the second year. Alternaria brassicicola multiplied on stalks exposed on the surface of field soil and was present on such residues after 24 months. Survival was less on residues buried in soil. Alternaria brassicae population increased in stalks exposed on the soil surface during the first months but decreased thereafter under the detection limit. Xanthomonas campestris cv. campestris populations fluctuated in time but 1 × 104 cells mg-1 stalk residue were still found after 24 months. Additionally, the four pathogens were present in residues of 11 commercial rapeseed crops that were analysed. The observed variation in population sizes of the pathogens between individual pieces of crop residues indicates a stochastic spread of pathogens. Unravelling the underlying processes will support the development of novel methods for sustainable disease prevention.
    Screening of biocontrol agents for control of foliar diseases
    Köhl, J. - \ 2009
    In: Recent Developments in Management of Plant Diseases / Gisi, U., Chet, I., Gullino, M.L., Dordrecht Heidelberg London New York : Springer (Plant Pathology in the 21st Century, Vol. 1. Vol. 1, part 2) - ISBN 9781402088032 - p. 107 - 119.
    apple scab pathogen - venturia-inaequalis - biological-control - botrytis-cinerea - trichoderma-harzianum - ulocladium-atrum - solar-radiation - powdery mildew - aphid honeydew - phyllosphere
    Candidate antagonists for the development of biocontrol agents have to fulfill many criteria. The criterion often investigated first in detail is the antagonistic potential of candidates against the target pathogen. However, candidates must also have high ecological competence, must be suitable for an economically feasible production and must be safe in use. Consequently, a broad range of criteria must be tested to fulfill the key factors for success of a biocontrol product. Assays are needed to test such major criteria in simple and inexpensive high throughput systems to exclude candidates in an early stage which may show strong antagonisms but do not fulfill other major criteria for a successful commercialization. The case of a screening program aimed at the biological control of apple scab caused by Venturia inaequalis is presented and discussed. Keywords Biological control - Foliar diseases - Screening - Selection criteria
    Identification and mapping of the novel apple scab resistance gene Vd3
    Soriano Soriano, J.M. ; Joshi, S.G. ; Kaauwen, M.P.W. van; Noordijk, Y. ; Groenwold, R. ; Henken, G. ; Weg, W.E. van de; Schouten, H.J. - \ 2009
    Tree Genetics and Genomes 5 (2009)3. - ISSN 1614-2942 - p. 475 - 482.
    x-domestica borkh. - venturia-inaequalis - microsatellite markers - technology dart - linkage maps - malus - vf - genome - region - r12740-7a
    Apple scab, caused by the fungal pathogen Venturia inaequalis, is one of the most devastating diseases for the apple growing in temperate zones with humid springs and summers. Breeding programs around the world have been able to identify several sources of resistance, the Vf from Malus floribunda 821 being the most frequently used. The appearance of two new races of V. inaequalis (races 6 and 7) in several European countries that are able to overcome the resistance of the Vf gene put in evidence the necessity of the combination of different resistance genes in the same genotype (pyramiding). Here, we report the identification and mapping of a new apple scab resistance gene (Vd3) from the resistant selection “1980-015-25” of the apple breeding program at Plant Research International, The Netherlands. This selection contains also the Vf gene and the novel V25 gene for apple scab resistance. We mapped Vd3 on linkage group 1, 1 cM to the south of Vf in repulsion phase to it. Based on pedigree analysis and resistance tests, it could be deduced that 1980-015-25 had inherited Vd3 from the founder “D3.” This gene provides resistance to the highly virulent EU-NL-24 strain of race 7 of V. inaequalis capable of overcoming the resistance from Vf and Vg.
    Construction of an integrated consensus map of the Apple genome based on four mapping populations
    N'Diaye, A. ; Weg, W.E. van de; Kodde, L.P. ; Koller, B. ; Dunemann, F. ; Thiermann, M. ; Tartarini, S. ; Gennari, F. ; Durel, C.E. - \ 2008
    Tree Genetics and Genomes 4 (2008)4. - ISSN 1614-2942 - p. 727 - 743.
    quantitative trait loci - genetic-linkage map - x-domestica borkh. - malus-pumila mill. - zea-mays l - scab resistance - venturia-inaequalis - rapd markers - qtl analysis - microsatellite markers
    An integrated consensus genetic map for apple was constructed on the basis of segregation data from four genetically connected crosses (C1¿=¿Discovery × TN10-8, C2¿=¿Fiesta × Discovery, C3¿=¿Discovery × Prima, C4¿=¿Durello di Forli × Fiesta) with a total of 676 individuals using CarthaGene® software. First, integrated female¿male maps were built for each population using common female¿male simple sequence repeat markers (SSRs). Then, common SSRs over populations were used for the consensus map integration. The integrated consensus map consists of 1,046 markers, of which 159 are SSR markers, distributed over 17 linkage groups reflecting the basic chromosome number of apple. The total length of the integrated consensus map was 1,032 cM with a mean distance between adjacent loci of 1.1 cM. Markers were proportionally distributed over the 17 linkage groups (¿ 2¿=¿16.53, df¿=¿16, p¿=¿0.41). A non-uniform marker distribution was observed within all of the linkage groups (LGs). Clustering of markers at the same position (within a 1-cM window) was observed throughout LGs and consisted predominantly of only two to three linked markers. The four integrated female¿male maps showed a very good colinearity in marker order for their common markers, except for only two (CH01h01, CH05g03) and three (CH05a02z, NZ02b01, Lap-1) markers on LG17 and LG15, respectively. This integrated consensus map provides a framework for performing quantitative trait locus (QTL) detection in a multi-population design and evaluating the genetic background effect on QTL expression.
    Interactions between yeasts, fungicides and apple fruit russeting
    Gildemacher, P.R. ; Heijne, B. ; Silvestri, M. ; Houbraken, J. ; Hoekstra, E. ; Theelen, B. ; Boekhout, T. - \ 2006
    FEMS Yeast Research 6 (2006)8. - ISSN 1567-1356 - p. 1149 - 1156.
    golden delicious apple - rhodotorula-glutinis - venturia-inaequalis - aureobasidium-pullulans - botrytis-cinerea - scab fungicides - ribosomal dna - microflora - sprays - mold
    The effect of inoculations with yeasts occurring on apple surfaces and fungicide treatments on the russeting of Elstar apples was studied. Captan, dithianon and a water treatment were implemented to study the interaction between the fungicides, the inoculated yeast species and Aureobasidium pullulans, and the development of russet. All yeast inoculations aggravated russet, but Rhodotorula glutinis, Sporidiobolus pararoseus and A. pullulans did so to a greater extent than the other species. Both captan and dithianon significantly reduced russeting. Denaturing gradient gel electrophoresis analysis showed that inoculations with R. glutinis and S. pararoseus seemed to suppress other yeast species present on the apple surface.
    The Vf gene for scrab resistance in apple is linked to sub-lethal genes
    Gao, Z.S. ; Weg, W.E. van de - \ 2006
    Euphytica 151 (2006)1. - ISSN 0014-2336 - p. 123 - 132.
    venturia-inaequalis - aflp markers - linkage maps - malus - progenies - selection - region
    V f is the most widely used resistance gene in the breeding for scab resistant apple cultivars. Distorted segregation ratios for V f -resistance have frequently been reported. Here we revealed that sub-lethal genes caused the distorted segregation. The inheritance of V f was examined in six progenies by testing linked molecular markers. Three progenies showed distorted segregations that could be explained by three sub-lethal genes (sl1, sl2 and sl3), of which sl1, sl2 were closely linked to V f . The s11 gene was located at about 14 cM from V f and expressed itself only in the presence of another independently segregating sub-lethal gene sl3. Only the double homozygous recessive genotypes (sl1sl1 sl3sl3) were lethal, which occurred at first as dwarf and poor vigour plants during the first three months after germination. The sl2 gene was also linked to V f and its lethality was expressed prior to seed germination and also required the homozygous recessive presence of sl3. The map position of sl3 has not yet been identified. The linkage of V f to sub-lethal genes usually results in a shortage of V f -resistant progenies. But in some exceptional crosses, it will lead to abundance of resistant seedling
    Impact of fungal drug transporters on fungicide sensitivity, multidrug resistance and virulence
    Waard, M.A. de; Andrade, A.C. ; Hayashi, K. ; Schoonbeek, H. ; Stergiopoulos, I. ; Zwiers, L.H. - \ 2006
    Pest Management Science 62 (2006)3. - ISSN 1526-498X - p. 195 - 207.
    atp-binding cassette - pathogen mycosphaerella-graminicola - azole antifungal agents - natural toxic compounds - yeast abc proteins - candida-albicans - botrytis-cinerea - aspergillus-nidulans - penicillium-digitatum - venturia-inaequalis
    Drug transporters are membrane proteins that provide protection for organisms against natural toxic products and fungicides. In plant pathogens, drug transporters function in baseline sensitivity to fungicides, multidrug resistance (MDR) and virulence on host plants. This paper describes drug transporters of the filamentous fungi Aspergillus nidulans (Eidam) Winter, Botrytis cinerea Pers and Mycosphaerella graminicola (Fu¿ckel) Schroter that function in fungicide sensitivity and resistance. The fungi possess ATP-binding cassette (ABC) drug transporters that mediate MDR to fungicides in laboratory mutants. Similar mutants are not pronounced in field resistance to most classes of fungicide but may play a role in resistance to azoles. MDR may also explain historical cases of resistance to aromatic hydrocarbon fungicides and dodine. In clinical situations, MDR development in Candida albicans (Robin) Berkhout mediated by ABC transporters in patients suffering from candidiasis is common after prolonged treatment with azoles. Factors that can explain this striking difference between agricultural and clinical situations are discussed. Attention is also paid to the risk of MDR development in plant pathogens in the future. Finally, the paper describes the impact of fungal drug transporters on drug discovery
    Microsatellite markers spanning the apple (Malus x domestica Borkh.) genome
    Silfverberg-Dilworth, E. ; Matasci, C.L. ; Weg, W.E. van de; Kaauwen, M.P.W. van; Walser, M. ; Kodde, L.P. ; Soglio, V. ; Gianfranceschi, L. ; Durel, C.E. ; Costa, F. ; Yamamoto, T. ; Koller, B. ; Gessler, C. ; Patocchi, A. - \ 2006
    Tree Genetics and Genomes 2 (2006)4. - ISSN 1614-2942 - p. 202 - 224.
    simple sequence repeats - scab resistance gene - fire-blight resistance - venturia-inaequalis - linkage maps - mildew resistance - pumila mill. - identification - pear - l.
    A new set of 148 apple microsatellite markers has been developed and mapped on the apple reference linkage map Fiesta x Discovery. One-hundred and seventeen markers were developed from genomic libraries enriched with the repeats GA, GT, AAG, AAC and ATC; 31 were developed from EST sequences. Markers derived from sequences containing dinucleotide repeats were generally more polymorphic than sequences containing trinucleotide repeats. Additional eight SSRs from published apple, pear, and Sorbus torminalis SSRs, whose position on the apple genome was unknown, have also been mapped. The transferability of SSRs across Maloideae species resulted in being efficient with 41% of the markers successfully transferred. For all 156 SSRs, the primer sequences, repeat type, map position, and quality of the amplification products are reported. Also presented are allele sizes, ranges, and number of SSRs found in a set of nine cultivars. All this information and those of the previous CH-SSR series can be searched at the apple SSR database ( to which updates and comments can be added. A large number of apple ESTs containing SSR repeats are available and should be used for the development of new apple SSRs. The apple SSR database is also meant to become an international platform for coordinating this effort. The increased coverage of the apple genome with SSRs allowed the selection of a set of 86 reliable, highly polymorphic, and overall the apple genome well-scattered SSRs. These SSRs cover about 85% of the genome with an average distance of one marker per 15 cM
    Identification of a major QTL together with several minor additive or epistatic QTLs for resistance to fire blight in apple in two related progenies
    Calenge, F. ; Drouet, D. ; Denance, C. ; Weg, W.E. van de; Brisset, M.N. ; Paulin, J.P. ; Durel, C.E. - \ 2005
    Theoretical and Applied Genetics 111 (2005)1. - ISSN 0040-5752 - p. 128 - 135.
    disease resistance - venturia-inaequalis - erwinia-amylovora - scab resistance - linkage maps - genes - organization - cultivars - evolution
    Although fire blight, caused by the bacterium Erwinia amylovora, is one of the most destructive diseases of apple (Malus x domestica) worldwide, no major, qualitative gene for resistance to this disease has been identified to date in apple. We conducted a quantitative trait locus (QTL) analysis in two F-1 progenies derived from crosses between the cultivars Fiesta and either Discovery or Prima. Both progenies were inoculated in the greenhouse with the same strain of E. amylovora, and the length of necrosis was scored 7 days and 14 days after inoculation. Additive QTLs were identified using the MAPQTL software, and digenic epistatic interactions, which are an indication of putative epistatic QTLs, were detected by two-way analyses of variance. A major QTL explaining 34.3-46.6% of the phenotypic variation was identified on linkage group (LG) 7 of Fiesta in both progenies at the same genetic position. Four minor QTLs were also identified on LGs 3, 12 and 13. In addition, several significant digenic interactions were identified in both progenies. These results confirm the complex polygenic nature of resistance to fire blight in the progenies studied and also reveal the existence of a major QTL on LG7 that is stable in two distinct genetic backgrounds. This QTL could be a valuable target in marker-assisted selection to obtain new, fire blight-resistant apple cultivars and forms a starting point for discovering the function of the genes underlying such QTLs involved in fire blight control.
    Analysis of summer epidemic progress of apple scab at different apple production systems in the Netherlands and Hungary
    Holb, I.J. ; Heijne, B. ; Withagen, J.C.M. ; Gáll, J.M. ; Jeger, M.J. - \ 2005
    Phytopathology 95 (2005)9. - ISSN 0031-949X - p. 1001 - 1020.
    venturia-inaequalis - disease-progress - powdery mildew - orchards - conidia - resistance - infection - spores - fungus - buds
    Two, 4-year studies on summer epidemic progress of apple scab were conducted at Randwijk, the Netherlands, from 1998 until 2001 and at Eperjeske, Hungary, from 2000 until 2003. Disease assessments were made on scab-susceptible cv. Jonagold. A range of nonlinear growth functions were fitted to a total of 96 disease progress curves (3 treatment classes x 2 plant parts x 2 disease measures x 4 years x 2 locations) of apple scab incidence and severity. The three-parameter logistic model gave the most consistent fit across three treatment classes in the experiment (integrated, organic-sprayed, and organic-unsprayed). Parameters estimated or calculated from the three-parameter logistic function were used to analyze disease progress. These were disease incidence and severity on the day of the first assessment (Y-s); final disease incidence or upper asymptote for incidence (Y-if) or severity (Y-sf); fruit incidence and severity on day 40, after which no new lesions on fruits appeared (Y-40); leaf incidence and severity on day 75, at which shoot growth stopped (Y-75); relative (beta) and "absolute" (theta) rates of disease progress; inflection point (M); and area under the disease progress curve (AUDPC(5)) standardized by the duration of the total epidemic. Comparisons among disease progress curves were made by Correlation and factor analysis followed by Varimax rotation. There were large differences but high positive correlations among the parameters Y-s, Y-f, theta, and AUDPC(5) across the three treatment classes. In the factor analysis, two factors accounted for more than 85% of the total variance for both incidence and severity. Factor I gave an overall description of epidemic progress of both scab incidence and severity and included the parameters Y-f, Y-40, Y-75, theta, and AUDPCs. Factor 2 identified a relationship between the relative rate parameter (P) and the inflection point (M) for severity and a relationship between disease incidence and severity. For an integrated or an organic orchard, theta, AUDPC(5), and one of Y-f or Y-75 (because of the link with host phenology) can characterize apple scab epidemics during summer. Based on these findings, improved scab management approaches were provided for integrated and organic apple production systems.
    Resistance gene analogues identified through the NBS-profiling method map close to major genes and QTL for disease resistance in apple
    Calenge, F. ; Linden, C.G. van der; Weg, W.E. van de; Schouten, H.J. ; Arkel, G. van; Denance, C. ; Durel, C.E. - \ 2005
    Theoretical and Applied Genetics 110 (2005)4. - ISSN 0040-5752 - p. 660 - 668.
    quantitative trait loci - venturia-inaequalis - scab resistance - mildew resistance - defense genes - co-localize - arabidopsis - homologs - potato - progeny
    We used a new method called nucleotide-binding site (NBS) profiling to identify and map resistance gene analogues (RGAs) in apple. This method simultaneously allows the amplification and the mapping of genetic markers anchored in the conserved NBS-encoding domain of plant disease resistance genes. Ninety-four individuals belonging to an F1 progeny derived from a cross between the apple cultivars Discovery and TN10-8 were studied. Two degenerate primers designed from the highly conserved P-loop motif within the NBS domain were used together with adapter primers. Forty-three markers generated with NBS profiling could be mapped in this progeny. After sequencing, 23 markers were identified as RGAs, based on their homologies with known resistance genes or NBS/leucine-rich-repeat-like genes. Markers were mapped on 10 of the 17 linkage groups of the apple genetic map used. Most of these markers were organized in clusters. Twenty-five markers mapped close to major genes or quantitative trait loci for resistance to scab and mildew previously identified in different apple progenies. Several markers could become efficient tools for marker-assisted selection once converted into breeder-friendly markers. This study demonstrates the efficiency of the NBS-profiling method for generating RGA markers for resistance loci in apple
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