Dissertation / PhD Thesis

FZJ-2015-01604

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Effects of Cercospora leaf spot disease on sugar beet genotypes with contrasting disease susceptibility

Schmittgen, S. (Corresponding Author)FZJ*

2015
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-95806-021-0

Please use a persistent id in citations: http://hdl.handle.net/2128/8436

Abstract: The fungal pathogen Cercospora beticola causes the most destructive foliar diseas eof sugar beet, namely Cercospora leaf spot (CLS), which results in economically important yield losses. Current breeding efforts aim at developing sugar beet lines with lower fungal susceptibility as well as high productivity to ensure reduced fungicide applications in the context of integrated pest management. However, the main challenge remains to select sugar beet genotypes that produce the required yield quality and quantity, and to quantify their defense ability. Well-established visual disease scoring can be supported and supplemented by new techniques that enable earlier disease detection and genotype resistance classification. In this thesis, visual disease scoring was combined with novel invasive and non-invasive techniques toanalyze shoot and root disease responses to Cercospora infection. The fungal growth within the sugar beet leaf tissue was quantified using molecular analysis of the fungal calmodulin gene. This allows for the pre-selection of resistant genotypes before disease symptoms were visible. It could be shown that plants with high susceptibility (HS) allowed a stronger fungal colonization in the leaf tissue than ones with low susceptibility (LS). These results correlated with the respective disease severity. The HS genotypes consistently displayed more severe disease symptoms than LS plants. In particular, the moderately susceptible (MS) genotype seemed to be a promising candidate according to its variable response indicating a more adaptable reaction to changing environmental conditions. Therefore, this MS genotype might produce more yield under low-to-moderate disease pressure compared with HS plants, which would be comparatively more strongly infected and deliver reduced yield. The cuticle forms a barrier between the plant and the environment and therefore provides resistance against pathogens. Cuticular wax may affect host-pathogen recognition and conidia adhesion on the leaf surface. In this study, LS plants werefound to contain larger amounts of cuticular waxes. Mature leaves, which showed reduced fungal colonization, also had higher wax levels than immature leaves. Further experiments are needed to investigate the precise role of sugar beet cuticular waxes on C. beticola infections.[...]

Keyword(s): Dissertation

Note: Universität Düsseldorf, Diss., 2014

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Contributing Institute(s):

1. Pflanzenwissenschaften (IBG-2)

Research Program(s):

1. 582 - Plant Science (POF3-582) (POF3-582)

Appears in the scientific report 2015

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Database coverage:

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