CISGENIC 'GALA' CONTAINING THE SCAB RESISTANCE GENE FROM MALUS FLORIBUNDA 821 AND THE FIRE BLIGHT RESISTANCE GENES FROM M. 'EVERESTE'

Five apple cultivars from the Czech Republic and 26 selections from the same country (a majority of them were resistant to scab) were included in the present study. M. robusta strain (Nr. 5) was used as a control with the highest level of resistance to fire blight. Another 7 cultivars with different levels of resistance or susceptibility to the disease were also evaluated. Selena and Nabella were found to be resistant, whereas Angold, Resista and Topaz were susceptible. Two HL selections were previously identified as highly resistant, 3 selections as medium resistant and 7 others as moderately susceptible. The rest of the 14 selections ranged from very high susceptible to medium susceptible. A high level of resistance was confirmed in 3 cultivars from Dresden-Pillnitz: Reanda, Remo and Rewena. Comparison of the parentage of the tested cultivars or selections with their level of resistance to fire blight suggests that most of the resistance comes from Malus floribunda, which was used in the course of their breeding as a donor of scab resistance. In one case, the source of the fire blight resistance was Starking Delicious cv.  

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A Novel Pear Scab (Venturia nashicola) Resistance Gene, Rvn3, from Interspecific Hybrid Pear (Pyrus pyrifolia × P. communis)

Plants ◽

10.3390/plants10122632 ◽

2021 ◽

Vol 10 (12) ◽

pp. 2632

Author(s):

Sewon Oh ◽

Hyeondae Han ◽

Daeil Kim

Keyword(s):

Resistance Gene ◽

Resistance Genes ◽

Interspecific Hybrid ◽

Dominant Gene ◽

Apple Scab ◽

Scab Resistance ◽

Hybrid Population ◽

Pyrus Pyrifolia ◽

Pear Scab ◽

Venturia Nashicola

Asian pear scab is a fungal disease caused by Venturia nashicola. The identification of genes conferring scab resistance could facilitate the breeding of disease-resistant cultivars. Therefore, the present study aimed to identify a scab-resistance gene using an interspecific hybrid population ((Pyrus pyrifolia × P. communis) × P. pyrifolia). Artificial inoculation of V. nashicola was carried out for two years. The segregation ratio (1:1) of resistant to susceptible individuals indicated that resistance to V. nashicola was inherited from P. communis and controlled by a single dominant gene. Based on two years phenotypic data with the Kruskal–Wallis test and interval mapping, 12 common markers were significantly associated with scab resistance. A novel scab resistance gene, Rvn3, was mapped in linkage group 6 of the interspecific hybrid pear, and co-linearity between Rvn3 and one of the apple scab resistance genes, Rvi14, was confirmed. Notably, an insertion in pseudo-chromosome 6 of the interspecific hybrid cultivar showed homology with apple scab resistance genes. Hence, the newly discovered Rvn3 was considered an ortholog of the apple scab resistance gene. Since the mapping population used in the present study is a pseudo-BC1 population, pyramiding of multiple resistance genes to pseudo-BC1 could facilitate the breeding of pear cultivars with durable resistance.

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Quantitative Trait Loci (QTL) Analysis Reveals Both Broad-Spectrum and Isolate-Specific QTL for Scab Resistance in an Apple Progeny Challenged with Eight Isolates of Venturia inaequalis

Phytopathology ◽

10.1094/phyto.2004.94.4.370 ◽

2004 ◽

Vol 94 (4) ◽

pp. 370-379 ◽

Cited By ~ 122

Author(s):

F. Calenge ◽

A. Faure ◽

M. Goerre ◽

C. Gebhardt ◽

W. E. Van de Weg ◽

...

Keyword(s):

Quantitative Trait Loci ◽

Resistance Gene ◽

Resistance Genes ◽

Quantitative Trait ◽

Venturia Inaequalis ◽

Scab Resistance ◽

Breeding Programs ◽

Apple Breeding ◽

Trait Loci ◽

New Races

The major scab resistance gene Vf, extensively used in apple breeding programs, was recently overcome by the new races 6 and 7 of the fungal pathogen Venturia inaequalis. New, more durable, scab resistance genes are needed in apple breeding programs. F1 progeny derived from the cross between partially resistant apple cv. Discovery and apple hybrid ‘TN10-8’ were inoculated in the greenhouse with eight isolates of V. inaequalis, including isolates able to overcome Vf. One major resistance gene, Vg, and seven quantitative trait loci (QTL) were identified for resistance to these isolates. Three QTL on linkage group (LG)12, LG13, and LG15 were clearly isolate-specific. Another QTL on LG5 was detected with two isolates. Three QTL on LG1, LG2, and LG17 were identified with most isolates tested, but not with every isolate. The QTL on LG2 displayed alleles conferring different specificities. This QTL co-localized with the major scab resistance genes Vr and Vh8, whereas the QTL on LG1 colocalized with Vf. These results contribute to a better understanding of the genetic basis of the V. inaequalis-Malus × domestica interaction.

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Apple Contains Receptor-like Genes Homologous to the Cladosporium fulvum Resistance Gene Family of Tomato with a Cluster of Genes Cosegregating with Vf Apple Scab Resistance

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2001.14.4.508 ◽

2001 ◽

Vol 14 (4) ◽

pp. 508-515 ◽

Cited By ~ 111

Author(s):

Boris A. Vinatzer ◽

Andrea Patocchi ◽

Luca Gianfranceschi ◽

Stefano Tartarini ◽

Hong-Bin Zhang ◽

...

Keyword(s):

Gene Family ◽

Resistance Gene ◽

Resistance Genes ◽

Transmembrane Domain ◽

Venturia Inaequalis ◽

Scab Resistance ◽

Common Disease ◽

Resistance Locus ◽

Cladosporium Fulvum ◽

High Quality

Scab caused by the fungal pathogen Venturia inaequalis is the most common disease of cultivated apple (Malus × domestica Borkh.). Monogenic resistance against scab is found in some small-fruited wild Malus species and has been used in apple breeding for scab resistance. Vf resistance of Malus floribunda 821 is the most widely used scab resistance source. Because breeding a high-quality cultivar in perennial fruit trees takes dozens of years, cloning disease resistance genes and using them in the transformation of high-quality apple varieties would be advantageous. We report the identification of a cluster of receptor-like genes with homology to the Cladosporium fulvum (Cf) resistance gene family of tomato on bacterial artificial chromosome clones derived from the Vf scab resistance locus. Three members of the cluster were sequenced completely. Similar to the Cf gene family of tomato, the deduced amino acid sequences coded by these genes contain an extracellular leucine-rich repeat domain and a transmembrane domain. The transcription of three members of the cluster was determined by reverse transcription-polymerase chain reaction to be constitutive, and the transcription and translation start of one member was verified by 5′ rapid amplification of cDNA ends. We discuss the parallels between Cf resistance of tomato and Vf resistance of apple and the possibility that one of the members of the gene cluster is the Vf gene. Cf homologs from other regions of the apple genome also were identified and are likely to present other scab resistance genes.

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Putative resistance gene markers associated with quantitative trait loci for fire blight resistance in Malus ‘Robusta 5’ accessions

BMC Genetics ◽

10.1186/1471-2156-13-25 ◽

2012 ◽

Vol 13 (1) ◽

pp. 25 ◽

Cited By ~ 45

Author(s):

Susan E Gardiner ◽

John L Norelli ◽

Nihal de Silva ◽

Gennaro Fazio ◽

Andreas Peil ◽

...

Keyword(s):

Quantitative Trait Loci ◽

Resistance Gene ◽

Quantitative Trait ◽

Fire Blight ◽

Blight Resistance ◽

Gene Markers ◽

Trait Loci

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Identification by genome scanning approach (GSA) of a microsatellite tightly associated with the apple scab resistance gene Vm

Genome ◽

10.1139/g05-036 ◽

2005 ◽

Vol 48 (4) ◽

pp. 630-636 ◽

Cited By ~ 49

Author(s):

A Patocchi ◽

M Walser ◽

S Tartarini ◽

G A.L Broggini ◽

F Gennari ◽

...

Keyword(s):

Molecular Markers ◽

Linkage Group ◽

Resistance Gene ◽

Resistance Genes ◽

Simple Sequence Repeat ◽

Apple Scab ◽

Scab Resistance ◽

Sequence Repeat ◽

Genome Scanning ◽

Simple Sequence

For all known major apple scab resistance genes except Vr, molecular markers have been published. However, the precise position of some of these genes, in the apple genome, remains to be identified. Knowledge about the relative position of apple scab resistance genes is necessary to preliminarily evaluate the probability of success of their pyramidization. Pyramidization of different resistance genes into the same genotype is a reliable way to create cultivars with durable apple scab resistance. Applying the genome scanning approach (GSA), we identified the linkage group of the scab resistance gene Vm, derived from Malus micromalus, and we found a new molecular marker tightly associated with the gene. The simple sequence repeat Hi07h02, previously mapped on linkage group 17, cosegregates with the Vm gene (no recombinants in the 95 plants tested). The already published sequence-characterized amplified region Vm marker OPB12687 was found to be linked at about 5 cM from the resistance gene and, therefore, this marker also maps on linkage group 17 of apple. This is the first report of the discovery of a major apple scab resistance gene on linkage group 17. The advantages of using GSA for the identification of molecular markers for qualitative traits are discussed.Key words: Malus, Venturia inaequalis, mapping, simple sequence repeat.

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Higher Copy Numbers of the Potato RB Transgene Correspond to Enhanced Transcript and Late Blight Resistance Levels

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-22-4-0437 ◽

2009 ◽

Vol 22 (4) ◽

pp. 437-446 ◽

Cited By ~ 72

Author(s):

James M. Bradeen ◽

Massimo Iorizzo ◽

Dimitre S. Mollov ◽

John Raasch ◽

Lara Colton Kramer ◽

...

Keyword(s):

Disease Resistance ◽

Late Blight ◽

Resistance Gene ◽

Resistance Genes ◽

Rna Silencing ◽

Late Blight Resistance ◽

Blight Resistance ◽

Transcript Levels ◽

Cultivated Potato ◽

Copy Numbers

Late blight of potato ranks among the costliest of crop diseases worldwide. Host resistance offers the best means for controlling late blight, but previously deployed single resistance genes have been short-lived in their effectiveness. The foliar blight resistance gene RB, previously cloned from the wild potato Solanum bulbocastanum, has proven effective in greenhouse tests of transgenic cultivated potato. In this study, we examined the effects of the RB transgene on foliar late blight resistance in transgenic cultivated potato under field production conditions. In a two-year replicated trial, the RB transgene, under the control of its endogenous promoter, provided effective disease resistance in various genetic backgrounds, including commercially prominent potato cultivars, without fungicides. RB copy numbers and transcript levels were estimated with transgene-specific assays. Disease resistance was enhanced as copy numbers and transcript levels increased. The RB gene, like many other disease resistance genes, is constitutively transcribed at low levels. Transgenic potato lines with an estimated 15 copies of the RB transgene maintain high RB transcript levels and were ranked among the most resistant of 57 lines tested. We conclude that even in these ultra–high copy number lines, innate RNA silencing mechanisms have not been fully activated. Our findings suggest resistance-gene transcript levels may have to surpass a threshold before triggering RNA silencing. Strategies for the deployment of RB are discussed in light of the current research.

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Six promising selections from the Hungarian apple breeding program for multiple resistance

International Journal of Horticultural Science ◽

10.31421/ijhs/11/3/594 ◽

2005 ◽

Vol 11 (3) ◽

Cited By ~ 2

Author(s):

M. Tóth

Keyword(s):

Powdery Mildew ◽

Fire Blight ◽

Molecular Genetic ◽

Apple Scab ◽

Breeding Program ◽

Scab Resistance ◽

Multiple Resistance ◽

Vf Gene ◽

Apple Breeding ◽

Malus Floribunda

An apple breeding program has been carried out at the Department of Fruit Science for more than a decade. Several apple selections have been released from the progenies of crosses in 1992 and 1993. Six candidates were submitted for national recognition out of the hybrids examined for more than a decade. The six selections are resistant against all the three most important apple diseases (apple scab, powdery mildew and fire blight). Scab resistance is controlled by the Vf gene originating from the species Malus floribunda 821 and transmitted by cultivar Prima. Heterozygote Vfvf genotype of the six cultivar candidates was proved by molecular genetic examinations of Dept. Genetics and Plant Breeding. Characteristics of these selections from 'Prima' progenies are shown on the base of our own observations.

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