Microscopic Studies of Scab Resistance Symptoms (Venturia Pirina) on Leaves of Pear Cultivars (Pyrus Communis)

Chevalier, Michel; Guérif, Philippe; Tellier, Marie; Cheve, F.; Lezec, M. Le; Lespinasse, Yves; Filmon, R.

doi:10.17660/actahortic.2002.596.92

Cited by 7 publications

(14 citation statements)

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“…, 1993; Ortega et al. , 1998), and less frequently for V. pirina (Stadelmann & Schwinn, 1982; Chevalier et al. , 2002) and V. nashicola (Park et al.…”

Section: Introductionmentioning

confidence: 99%

A new scab‐like disease on apple caused by the formerly saprotrophic fungus Venturia asperata

Caffier¹,

Cam²,

Expert³

et al. 2012

Plant Pathology

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Atypical scab-like symptoms were reported for the first time in 2007 in the south of France on fruits of apple cultivars carrying the Rvi6 (=Vf) major resistance gene to Venturia inaequalis. With microscopic observations, nucleotide sequence data and pathological tests, it was shown that the causal agent was Venturia asperata. Scanning electron microscopy was used to compare its infection process and conidiogenesis to those of Venturia inaequalis on apple and Venturia pirina on pear. Venturia asperata produced fewer hyphae and fewer spores than the two other Venturia species, and resulted in weaker symptoms. This fungal species was previously described as a saprotroph on apple leaf litter. This is the first report of damage on apple fruits caused by V. asperata. Changes in host and cultural practices may have created a new context favourable for the emergence of this pathogen. It was also detected on symptomless leaves and on overwintered leaves on the ground. Pseudothecia developed on overwintered leaves and released ascospores over a 2-month period from the end of March until the end of May, suggesting that the fungus is able to survive from season to season. However, it is not yet known if this new disease will establish over coming years and become an emergent disease.

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“…, 1993; Ortega et al. , 1998), and less frequently for V. pirina (Stadelmann & Schwinn, 1982; Chevalier et al. , 2002) and V. nashicola (Park et al.…”

Section: Introductionmentioning

confidence: 99%

A new scab‐like disease on apple caused by the formerly saprotrophic fungus Venturia asperata

Caffier¹,

Cam²,

Expert³

et al. 2012

Plant Pathology

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“…The behaviour of a cultivar seems strongly related to the local population structure of the pathogen (Shabi et al 1972). The heterogeneity of the resistance level of the cultivars (Chevalier et al 2002) and the influence of environmental conditions are the main hurdles to understanding the host-parasite relationships. A cultivar can be resistant in one geographic area, but susceptible in another (Brown 1960).…”

Section: Introductionmentioning

confidence: 99%

A new pear scab resistance gene Rvp1 from the European pear cultivar ‘Navara’ maps in a genomic region syntenic to an apple scab resistance gene cluster on linkage group 2

Bouvier

Bourcy

Boulay

et al. 2011

Tree Genetics & Genomes

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Scab, caused by the ascomycete fungus Venturia pirina, leads to severe damage on European pear varieties resulting in a loss of commercial value and requiring frequent use of fungicides. Identifying scab resistance genes, developing molecular markers linked to these genes and establishing marker-assisted selection would be an effective way to improve European pear breeding for scab resistance. Most of the European pear cultivars (Pyrus communis) are currently reported to be sensitive. The pear cultivar ‘Navara’ was shown to carry a major scab resistance gene whose phenotypic expression in seedling progenies was a typical stellate necrosis symptom. The resistance gene was called Rvp1, for resistance to V. pirina, and was mapped on linkage group 2 of the pear genome close to microsatellite marker CH02b10. This genomic region is known to carry a cluster of scab resistance genes in apple indicating a first functional synteny for scab resistance between apple and pear

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“…Apple is considered a non-host for V. pirina too (Stehmann et al 2001), which may show potential for breeding provided the incompatibility barrier can be circumvented. Non-host interactions have been observed between V. pirina and the apple cultivars 'Gala' (susceptible to apple scab) and 'Discovery' (polygenic resistant to apple scab) and vice versa between V. inaequalis and the pear cultivars 'Pierre Corneille' (susceptible to V. pirina) and 'Navara' (polygenic resistant to V. pirina) (Chevalier et al 2002). These interactions provide an interesting model system for studying non-host resistance in related species, while providing an opportunity to breed for durable scab resistance.…”

Section: Discussionmentioning

confidence: 99%

“…on European pear {Pyrus communis L.) (Villalta et al 2004) and V. nashicola Tanaka & Yamamoto on Asian pear (Ishii & Yanase 2000), is a serious disease that can cause heavy crop losses if left untreated (Chevalier et al 2002;Villalta et al 2004;Abe et al 2008). It is most severe in regions where regular rainfall or heavy dews occur in the spring when young leaves are expanding and are at their most susceptible (Li & Zhao 2001;Villalta et al 2004;Spotts et al 2005).…”

Section: Introductionmentioning

confidence: 99%

“…However, a number of varieties have been identified with sufficiently high levels of resistance to provide potential for resistance breeding (Chevalier et al 2002). In contrast, cultivars of the Asian pears Pyrus pyrifolia Nakai and Pyrus x bretschneideri Rhed., which generally are susceptible to V. nashicola Tanaka & Yamamoto, are highly resistant or immune to infection by V. pirina (Vondracek 1982;Chevalier et al 2002;212 New Zealand Journal of Crop andHorticultural Science, 2009, Vol. 37 Villalta et al 2004;Postman et al 2005), because they are non-hosts for this species.…”

Section: Introductionmentioning

confidence: 99%

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Resistance to scab caused byVenturis pirinain interspecific pear (Pyrusspp.) hybrids

Brewer¹,

Alspach

Morgan

et al. 2009

New Zealand Journal of Crop and Horticultural Science

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The genetics of resistance to Venturia pirina was investigated from 2002 to 2004 on 11 families derived from interspecific crosses between European and Asian pear species. Nearly complete leaf resistance to V. pirina was identified in all progeny of families with at least 50% Asian pear (Pyrus pyrifolia and/or Pyrus × bretschneideri) ancestry, but up to 26% of these trees exhibited fruit scab incidence in any one of three years. However, between 67% and 80% of the scab leaf resistant individuals had fruit russet spotting owing to scab infection in one or more years over the duration of the trial and between 14% and 36% of the leaves were affected by russet spot. The level of affected individuals did not appear to decrease with increasing proportion of Asian parentage for leaves or fruit. In contrast, reference families derived from European pears and many of the families with 12-25% Asian parentage were almost 100% susceptible to scab on both leaves and fruit. In European families, only 2% of these individuals had leaves affected by russet spotting, whereas an average of 23% of fruit were affected. The genetics of non-host resistance is discussed.

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Microscopic Studies of Scab Resistance Symptoms (Venturia Pirina) on Leaves of Pear Cultivars (Pyrus Communis)

Cited by 7 publications

References 0 publications

A new scab‐like disease on apple caused by the formerly saprotrophic fungus Venturia asperata

A new scab‐like disease on apple caused by the formerly saprotrophic fungus Venturia asperata

A new pear scab resistance gene Rvp1 from the European pear cultivar ‘Navara’ maps in a genomic region syntenic to an apple scab resistance gene cluster on linkage group 2

Resistance to scab caused byVenturis pirinain interspecific pear (Pyrusspp.) hybrids

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