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Resistance against fruit tree canker in apple

evaluation of disease symptoms, histopathological and RNA-seq analyses in different cultivars, genetic variation of Neonectria ditissima

Ghasemkhani, Marjan (2015). Resistance against fruit tree canker in apple. Diss. (sammanfattning/summary) Alnarp : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2015:77
ISBN 978-91-576-8352-6
eISBN 978-91-576-8353-3
[Doctoral thesis]

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Neonectria ditissima (formerly Neonectria galligena, anamorph Cylindrocarpon heteronema) is the causal agent of fruit tree canker, which is regarded as a serious economic problem in apple production. This fungus is closely associated with mild and wet conditions, and climate therefore has an important impact on its geographic distribution. Notable damage to apple trees is especially common in, e.g., North-Western Europe. Complete resistance has not yet been reported. In addition, no major genes have as yet been identified and resistance appears to be controlled mainly by additive gene action.
Apple cultivars varied significantly in level of partial resistance towards apple canker after artificial inoculation of detached shoots and/or potted trees with macroconidia of N. ditissima. The inter-specific crabapple hybrid ‘Prairifire’ showed the least damage, indicating that valuable sources of resistance can be found in Malus species. Neonectria ditissima could be detected in artificially infected apple trees using a species-specific β-tubulin gene-based qPCR assay two months after inoculation. When quantified in different cultivars, a positive relationship between N. ditissima biomass and the size of canker-induced lesions was found. Interaction between plant and pathogen was studied using light microscopy of apple woody tissue; fungal hyphae were found in all cell types, and gel formation was observed in both a susceptible and a resistant cultivar but infection appears to progress more rapidly in the susceptible cultivar. Genetic variation among different N. ditissima isolates was investigated using SSR and AFLP markers. Comparatively low levels of genetic differentiation among orchards indicate that gene flow is prominent. Analyses of single-ascospore isolates from the same perithecia suggest that this fungus is heterothallic and therefore outcrossing. Furthermore, a focused genomics approach was applied in order to identify differentially expressed genes in response to fungal attack on apple trees. Obtained data indicate that apple cultivars inoculated with N. ditissima exhibit significant upregulation of defence-related genes and genes involved in detoxification, peroxidase-related reactions, phenylpropanoid metabolism and the lignification process.

Authors/Creators:Ghasemkhani, Marjan
Title:Resistance against fruit tree canker in apple
Subtitle:evaluation of disease symptoms, histopathological and RNA-seq analyses in different cultivars, genetic variation of Neonectria ditissima
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2015
Number of Pages:64
IGhasemkhani M., Liljeroth E., Sehic J., Zborowska A. and Nybom, H. (2015). Cut-off shoots method for estimation of partial resistance in apple cultivars to fruit tree canker caused by Neonectria ditissima. Acta Agriculturae Scandinavica, Section B-Soil & Plant Science, 65(5): 412-421.
IIGarkava-Gustavsson L., Ghasemkhani M., Zborowska A., Englund J.-E., Lateur M. and van de Weg E. Approaches for evaluation of resistance to European canker (Neonectria ditissima) in apple. Acta Hortic. (In press).
IIIGhasemkhani M., Holefors A., Marttila S., Zborowska A., Rur M., Rees-George J., Nybom H., Everett K., Scheper R. and Garkava-Gustavsson L. Detection and quantification of Neonectria ditissima in apple trees by real-time quantitative PCR and visualization by microscopy. (Submitted).
IVGhasemkhani M., Garkava-Gustavsson L., Liljeroth E. and Nybom H. Assessment of diversity and genetic relationships of Neonectria ditissima: the causal agent of fruit tree canker. (Manuscript).
VGhasemkhani M., Canbäck B., Alexandersson E., Nybom H. and Garkava-Gustavsson L. Identification of differentially expressed genes associated with response to fruit tree canker in apple using RNA-Seq analysis. (Manuscript).
Place of Publication:Alnarp
Publisher:Department of Plant Breeding, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-8352-6
ISBN for electronic version:978-91-576-8353-3
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:H Protection of plants and stored products > H20 Plant diseases
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 404 Agricultural Biotechnology > Plant Biotechnology
Agrovoc terms:cankers, apples, variteties, genetic variation, defense mechanisms, rna sequence
Keywords:anatomy, β-tubulin gene, defence mechanism, genetic variation, mating system, qPCR, RNA-Seq, transcriptome
Permanent URL:
ID Code:12495
Faculty:LTV - Fakulteten för landskapsarkitektur, trädgårds- och växtproduktionsvetenskap
Department:(LTJ, LTV) > Department of Plant Breeding (from 130101)
Deposited By: Mrs Marjan Ghasemkhani
Deposited On:19 Aug 2015 14:09
Metadata Last Modified:10 Sep 2020 13:41

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