scholarly journals New North American isolates of Venturia inaequalis can overcome apple scab resistance of Malus floribunda 821

2019 ◽  
Author(s):  
David Papp ◽  
Jugpreet Singh ◽  
David Gadoury ◽  
Awais Khan
Keyword(s):  
New York ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Venturia Inaequalis ◽  
Durable Resistance ◽  
Apple Scab ◽  
Scab Resistance ◽  
Breeding Programs ◽  
Malus Floribunda

AbstractApple scab, caused by Venturia inaequalis (Cke.) Wint., is a destructive fungal disease of major apple cultivars worldwide, most of which are moderately to highly susceptible. Thus, development of scab resistant cultivars is one of the highest priorities of apple breeding programs. The principal source of resistance for breeding programs has been the scab resistance gene Rvi6 that originated from the Japanese crabapple Malus floribunda (Sieb.) sel. 821. Isolates of V. inaequalis able to overcome Rvi6 have been identified in Europe, but have not yet been reported on the American continents. We recently discovered scab infection on M. floribunda 821 trees in a research orchard at Geneva, New York, USA, where approximately 10% of the leaves bore profusely sporulating apple scab lesions, many of which had coalesced to cover entire leaves. Chlorosis and pinpoint pitting symptoms typical of failed infections by V. inaequalis on hosts bearing the Rvi6 and Rvi7 genes were also observed. We assessed genetic diversity and population genetic structure of six V. inaequalis isolates collected from M. floribunda 821, one isolate from ‘Nova Easygro’, one isolate from ‘Golden Delicious’ and two isolates from Europe (11 isolates in total) using 16,321 genome-wide SNPs. Population genetic structure and PCA separated the isolates into distinct European and USA groups. The forgoing suggests that the new Rvi6 virulent isolates emerged within USA populations, rather than being transported from Europe. The overcoming of resistance in M. floribunda 821 but not in descendant cultivars suggests that durable resistance to apple scab will require a more comprehensive understanding of Rvi6 mediated resistance in diverse genetic backgrounds.

scholarly journals New North American Isolates of Venturia inaequalis Can Overcome Apple Scab Resistance of Malus floribunda 821

Plant Disease ◽  
2020 ◽  
Vol 104 (3) ◽  
pp. 649-655 ◽  
Author(s):  
David Papp ◽  
Jugpreet Singh ◽  
David Gadoury ◽  
Awais Khan
Keyword(s):  
Genetic Structure ◽  
Population Genetic Structure ◽  
North American ◽  
Population Genetic ◽  
Venturia Inaequalis ◽  
Durable Resistance ◽  
Apple Scab ◽  
Scab Resistance ◽  
Breeding Programs ◽  
Malus Floribunda

Apple scab, caused by Venturia inaequalis, is a destructive fungal disease of major apple cultivars worldwide, most of which are moderately to highly susceptible. Thus, development of scab resistant cultivars is one of the highest priorities of apple breeding programs. The principal source of resistance for breeding programs has been the scab resistance gene Rvi6 that originated from the Japanese crabapple Malus floribunda (Sieb.) sel. 821. Isolates of V. inaequalis able to overcome Rvi6 have been identified in Europe, but have not yet been reported on the American continents. We recently discovered scab infection on M. floribunda 821 trees in a research orchard at Geneva, NY, U.S.A., where approximately 10% of the leaves bore profusely sporulating apple scab lesions, many of which had coalesced to cover entire leaves. We observed both chlorosis, typical to Rvi6, and pinpoint pitting symptoms typical to failed infections by V. inaequalis on hosts bearing the Rvi7 gene. We assessed genetic diversity and population genetic structure of 11 V. inaequalis isolates in total, of North American and European origin, isolated from M. floribunda 821, ‘Nova Easygro’, ‘Golden Delicious’, TSR33T239, ‘Schone van Boskoop’, and ‘Prima’, using 16,321 genome-wide SNPs. Population genetic structure and PCA separated the isolates into distinct European and U.S. groups. The forgoing suggests that the new Rvi6 virulent isolates emerged within U.S. populations, rather than being transported from Europe. The complete resistance breakdown in M. floribunda 821 but not in descendant cultivars, which kept their field resistance, suggests that durable resistance to apple scab will require a more comprehensive understanding of Rvi6 mediated resistance in diverse genetic backgrounds.

scholarly journals Population Genetic Structure of Apple Scab (Venturia inaequalis (Cooke) G. Winter) in Iran

PLoS ONE ◽  
2016 ◽  
Vol 11 (9) ◽  
pp. e0160737 ◽  
Author(s):  
Leila Ebrahimi ◽  
Khalil-Berdi Fotuhifar ◽  
Mohammad Javan Nikkhah ◽  
Mohammad-Reza Naghavi ◽  
Niranjan Baisakh
Keyword(s):  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Venturia Inaequalis ◽  
Apple Scab

scholarly journals Correction: Population Genetic Structure of Apple Scab (Venturia inaequalis (Cooke) G. Winter) in Iran

PLoS ONE ◽  
2016 ◽  
Vol 11 (11) ◽  
pp. e0167415 ◽  
Author(s):  
Leila Ebrahimi ◽  
Khalil-Berdi Fotouhifar ◽  
Mohammad Javan Nikkhah ◽  
Mohammad-Reza Naghavi ◽  
Niranjan Baisakh
Keyword(s):  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Venturia Inaequalis ◽  
Apple Scab

scholarly journals Ten Years of VINQUEST: First Insight for Breeding New Apple Cultivars With Durable Apple Scab Resistance

Plant Disease ◽  
2020 ◽  
Vol 104 (8) ◽  
pp. 2074-2081 ◽  
Author(s):  
Andrea Patocchi ◽  
Andreas Wehrli ◽  
Pierre-Henri Dubuis ◽  
Annemarie Auwerkerken ◽  
Carmen Leida ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Venturia Inaequalis ◽  
Durable Resistance ◽  
Apple Scab ◽  
Resistance Breeding ◽  
Scab Resistance ◽  
Data Points ◽  
Resistance Breakdown ◽  
Apple Cultivars ◽  
Apple Production

Apple scab, caused by Venturia inaequalis, is a major fungal disease worldwide. Cultivation of scab-resistant cultivars would reduce the chemical footprint of apple production. However, new apple cultivars carrying durable resistances should be developed to prevent or at least slow the breakdown of resistance against races of V. inaequalis. One way to achieve durable resistance is to pyramid multiple scab resistance genes in a cultivar. The choice of the resistance genes to be combined in the pyramids should take into account the frequency of resistance breakdown and the geographical distribution of apple scab isolates able to cause such breakdowns. In order to acquire this information and to make it available to apple breeders, the VINQUEST project ( www.vinquest.ch ) was initiated in 2009. Ten years after launching this project, 24 partners from 14 countries regularly contribute data. From 2009 to 2018, nearly 9,000 data points have been collected. This information has been used to identify the most promising apple scab resistance genes for developing cultivars with durable resistance, which to date are: Rvi5, Rvi11, Rvi12, Rvi14, and Rvi15. As expected, Rvi1, together with Rvi3 and Rvi8, were often overcome, and have little value for scab resistance breeding. Rvi10 may also belong to this group. On the other hand, Rvi2, Rvi4, Rvi6, Rvi7, Rvi9, and Rvi13 are still useful for breeding, but their use is recommended only in extended pyramids of ≥3 resistance genes.

Population Genetic Structure of Blanding's Turtles (Emydoidea blandingii) in New York

2016 ◽  
Vol 50 (1) ◽  
pp. 70-76 ◽  
Author(s):  
Eric M. McCluskey ◽  
Stephen W. Mockford ◽  
Kylie Sands ◽  
Tom B. Herman ◽  
Glenn Johnson ◽  
...  
Keyword(s):  
New York ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Emydoidea Blandingii

scholarly journals Scab resistance in Malus sp. progenies - inheritance and resistance stability

2003 ◽  
Vol 9 (1) ◽  
Author(s):  
M. G. Tóth ◽  
Sz. Kovács ◽  
Zs. D. Rozsnyay
Keyword(s):  
Open Field ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Female Parent ◽  
Male Parent ◽  
Scab Resistance ◽  
Malus Prunifolia ◽  
Malus Floribunda ◽  
Artificial Inoculations ◽  
Positive Effect

Susceptibility of progenies of some Ma/us species to apple scab was evaluated. Susceptibility of hybrid families was observed first in greenhouse after artificial inoculations by the suspension of the pathogen, Venturia inaequalis (Cooke) Wint., then in open field. The Hungarian type of Malus floribunda, which proved to be scab resistant in our examinations, has a positive effect on the segregation of progenies to resistant and susceptible individuals as a male parent, not depending on the rate of susceptibility of the other parent. However, the German type of Malus floribunda and Malus prunifolia act as dominant, highly susceptible parents. Malus x purpurea and Malus baccata, which proved to be highly susceptible to apple scab in open field and in artificial inoculations, transmits its susceptibility only slightly to its progenies as a male parent. According to our experiments, the inheritance of scab resistance of Malus floribunda cannot be considered as monogenic, as published by other authors. Scab susceptibility of parents influences the segregation of progenies to resistant or susceptible individuals. The moderately scab susceptible `Idared' as female parent has a statistically proved positive effect on the segregation of its progenies. More factors indicate the appearance of a new race of Venturia inaequalis (Cke.) Wint.: change of the symptoms in the greenhouse; considerable increase of susceptible individuals after greenhouse inoculation in 1997; more and more progenies of the male parent Malus floribunda became susceptible to scab in open field.

scholarly journals Molecular Screening of Some Apple Progenies for Detection Vf Gene Using Marker Assisted Selection

2021 ◽  
Vol 78 (2) ◽  
pp. 36
Author(s):  
Georgeta BIVOLARIU (GUZU) ◽  
Ioan ZAGRAI ◽  
Luminița ZAGRAI ◽  
Mirela Irina CORDEA ◽  
Claudiu MOLDOVAN
Keyword(s):  
Resistance Gene ◽  
Fruit Quality ◽  
Marker Assisted Selection ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Molecular Screening ◽  
Breeding Programs ◽  
Vf Gene ◽  
Local Variety ◽  
Malus Floribunda

Apple scab, caused by Venturia inaequalis is one of the most damaging pathogens that affects apple species. Cross combinations were made between Auriu de Bistrița cv. (female genitor) - a valuable local variety in terms of fruit quality but only tolerant to scab, and Florina cv. (male genitor) used as a donor of Vf resistance gene. It was first detected in Malus floribunda Clone 821, which was later transferred to commercial varieties by different breeding programs. To confirm the presence of Vf gene, progenies resulting from the mentioned combination were tested with MAS (Marker Assited Selection), using two dominant primers pairs (AM19, U1400), and another one codominant (AL07) used to distinguish homozygous and heterozygous genotypes. After the crossing combination, a number of twenty-six hybrids were obtained, of which 50% (13 hybrids) were clasified as resistant (heterozygous), respectively 50% (13 hybrids) as susceptible (recessive homozygotes), so the Mendelian ratio was confirmed.

scholarly journals TheVenturiaApple Pathosystem: Pathogenicity Mechanisms and Plant Defense Responses

2009 ◽  
Vol 2009 ◽  
pp. 1-10 ◽  
Author(s):  
Gopaljee Jha ◽  
Karnika Thakur ◽  
Priyanka Thakur
Keyword(s):  
Plant Pathogen ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Resistance Breeding ◽  
Defense Responses ◽  
Scab Resistance ◽  
Plant Defense Responses ◽  
Polygenic Resistance ◽  
Breeding Programs ◽  
Plant Pathogen Interactions

Venturia inaequalisis the causal agent of apple scab, a devastating disease of apple. We outline several unique features of this pathogen which are useful for molecular genetics studies intended to understand plant-pathogen interactions. The pathogenicity mechanisms of the pathogen and overview of apple defense responses, monogenic and polygenic resistance, and their utilization in scab resistance breeding programs are also reviewed.

scholarly journals Field apple scab susceptibility of a diverse Malus germplasm collection identifies potential sources of resistance for apple breeding

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
David Papp ◽  
Liqiang Gao ◽  
Ranjita Thapa ◽  
Dan Olmstead ◽  
Awais Khan
Keyword(s):  
New York ◽  
Resistance Genes ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Genetic Research ◽  
Germplasm Collection ◽  
Resistance Breeding ◽  
Scab Resistance ◽  
Sources Of Resistance ◽  
Apple Breeding

Abstract Background Breeding for resistance to apple scab (caused by Venturia inaequalis), the most devastating fungal disease of apples, relies on genetic resources maintained in germplasm collections. Methods To identify new sources of scab resistance, we evaluated 177 Malus accessions, including 27 primary and 13 hybrid Malus species from diverse geographical origins, in an orchard at Geneva, New York. We also screened a differential host set for 2 years to monitor for changes in the effectiveness of ten known scab resistance genes, which allowed us to confirm the presence of virulent pathogen races in the orchard. Results We found that ~ 37% of the wild Malus accessions and domesticated cultivars were resistant to apple scab in the field. Several of these accessions were unrelated to sources of previously known resistance genes and are promising for apple scab genetic research and resistance breeding. Cultivars carrying the Rvi6 (Vf) gene from Malus floribunda clone 821, e.g. ‘Liberty’ or ‘Florina’, remained resistant despite the breakdown of Rvi6. ‘Demir’, a Malus hybrid from Turkey, and ‘Chisel Jersey’, a traditional English hard cider cultivar, showed fewer symptoms than the Rvi6 resistant cultivar ‘Prima’. Races 1 to 7 and 9 of V. inaequalis were present in the orchard, but no scab was observed on the indicator host accessions for races 11 and 12. Conclusions Detailed and systematic screening of Malus germplasm identified resistant and moderately resistant donor accessions based on resistance reaction types. These accessions are promising for use in future genetic studies to identify novel sources of scab resistance alleles for apple breeding to develop cultivars with durable apple scab resistance.

scholarly journals Inheritance studies of apple scab resistance and identification of Rvi14, a new major gene that acts together with other broad-spectrum QTL

Genome ◽  
2008 ◽  
Vol 51 (8) ◽  
pp. 657-667 ◽  
Author(s):  
V. Soufflet-Freslon ◽  
L. Gianfranceschi ◽  
A. Patocchi ◽  
C.-E. Durel
Keyword(s):  
Broad Spectrum ◽  
Quantitative Resistance ◽  
Venturia Inaequalis ◽  
Major Gene ◽  
Durable Resistance ◽  
Apple Scab ◽  
Genomic Region ◽  
Scab Resistance ◽  
Common Disease ◽  
Breeding Programmes

Scab, caused by the fungal pathogen Venturia inaequalis , is the most common disease of cultivated apple (Malus ×domestica). The fungal races 6 and 7 have now overcome the major resistance gene Vf, which is widely used in apple breeding programmes. New breeding strategies to achieve durable resistance are thus necessary. The aim of this study was to determine the genetic basis of quantitative resistance of the apple cultivar ‘Dülmener Rosenapfel’, known to be scab resistant under different environmental conditions. An F1 progeny derived from the cross between the susceptible cultivar ‘Gala’ and ‘Dülmener Rosenapfel’ was tested in a greenhouse with a multi-isolate inoculum of V. inaequalis. Rvi14, a new major gene that conditions a chlorotic-type reaction, was mapped on linkage group (LG) 6 in a genomic region not known to be involved in disease resistance. A further three quantitative trait loci (QTL) for resistance were identified. One co-localized with Rvi14 on LG6, whereas the remaining two were detected on LG11 and LG17, in genomic regions already reported to carry broad-spectrum QTL in other genetic backgrounds. Since a selective genotyping approach was used to detect QTL, an expectation-maximization (EM) computation was used to estimate the corrected QTL contributions to phenotypic variation and was validated by entire progeny genotyping.

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