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The late blight pathogen, Phytophthora infestans

interaction with the potato plant and inoculum sources

Widmark, Anna-Karin (2010). The late blight pathogen, Phytophthora infestans. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2010:2
ISBN 978-91-576-7479-1
[Doctoral thesis]

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Abstract

The oomycete, Phytophthora infestans, is one of the most important plant pathogens worldwide. This thesis focuses on the late blight pathogen and its host, potato (Solanum tuberosum), and the interaction between these two organisms. Resistance to P. infestans was evaluated histologically, using leaves of potato cultivars with varying levels of general resistance. Preinfectional events could be ruled out as discriminating factors determining the level of resistance in the cultivars studied. After penetration of the pathogen into the leaf tissue there were significant differences between cultivars in hyphal growth and branching. The biochemical response of the tubers to pathogens, more specifically the accumulation of sesquiterpenoid metabolites and their biological effect on P. infestans was examined. Two unique sesquiterpenoid metabolites were isolated from tubers. The influence on mycelial growth of P. infestans of these compounds and of five naturally occurring plant sesquiterpenoids was tested. The two metabolites, isolated from tubers, induced a slight growth stimulation. All other compounds tested, suppressed the growth of the pathogen. The population structure of P. infestans in one single field in southwest Sweden was analysed with the aim to study the origin of the primary infections. Mitochondrial DNA, mating type and SSR-genotype were used as markers. Some foci were monomorphic for all markers, while other foci displayed a large proportion of unique genotypes. This was taken as evidence that inoculum had come both from tubers and oospores within this field. The dynamics of an epidemic and sexual reproduction of P. infestans was investigated in an experimental field inoculated with six different isolates of the pathogen. Three weeks after inoculation sampling was done. The following year, P. infestans isolates were baited from soil samples taken from the field. Parentage analysis, based on SSR markers, showed that recombinant genotypes from the inoculum isolates were present in the soil samples. These findings demonstrate that oospores produced during a summer epidemic in Sweden can overwinter and cause infection the next year.

Authors/Creators:Widmark, Anna-Karin
Title:The late blight pathogen, Phytophthora infestans
Subtitle:interaction with the potato plant and inoculum sources
Year of publishing :2010
Volume:2010:2
Number of Pages:67
Papers/manuscripts:
NumberReferences
ALLI. Berggren, B., Widmark, A.-K., Umaerus, V. (1988). The expression of general resistance to late blight (Phytophthora infestans) in potato leaves. Potato Research 31, 611-616. II. Engström, K., Widmark, A.-K., Brishammar, S., Helmersson, S . (1999). Antifungal activity to Phytophthora infestans of sesquiterpenoids from infected tubers. Potato Research 42, 43-50. III. Widmark, A.-K., Andersson, B., Cassel-Lundhagen A., Sandström, M., Yuen, J. (2007). Phytophthora infestans in a single field in southwest Sweden early in spring: symptoms, spatial distribution and genotypic variation. Plant Pathology 56, 573-579. IV. Widmark, A.-K., Andersson, B., Sandström, M., Yuen, J. Tracking Phytophthora infestans with SSR markers within and between seasons (manuscript).
Place of Publication:Uppsala
Associated Programs and Other Stakeholders:Z - SLU - Libray > Odla mera
ISBN for printed version:978-91-576-7479-1
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:solanum tuberosum, phytophthora infestans, blight, plant diseases, host pathogen relations, disease resistance, inoculation, genotypes, genetic markers, phytoalexins, sesquiterpenoids, sweden
Keywords:infection process, oospores, Phytophthora infestans, phytoalexins, late blight, resistance, sexual reproduction
URN:NBN:urn:nbn:se:slu:epsilon-3036
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-3036
ID Code:2210
Department:(NL, NJ) > Dept. of Forest Mycology and Plant Pathology
(S) > Dept. of Forest Mycology and Plant Pathology
Deposited By: Anna-Karin Widmark
Deposited On:11 Jan 2010 00:00
Metadata Last Modified:22 Mar 2015 15:14

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