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Verticillium longisporum, infection, host range, prevalence and plant defence responses

Johansson, Anna (2006). Verticillium longisporum, infection, host range, prevalence and plant defence responses. Uppsala : Sveriges lantbruksuniv. ; -
ISBN 91-576-7153-2
[Licentiate thesis]

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Verticillium wilt is the major disease responsible for yield losses in oilseed crops in Sweden today. V. longisporum is the most prevalent Verticillium pathogen found in Swedish soils, but V. dahliae and V. tricorpus can also be found. Very little data exists concerning the infection pattern, host range and triggered defence responses in plants toward V. longisporum. This thesis aims to extend our knowledge about V. longisporum and its host. The infection process of V. longisporum and V. dahliae in oilseed crops was compared. V. longisporum was found to colonise oilseed crops through lateral roots and root hairs, compared with V. dahliae that colonise via the primary roots. At plant maturation, V. longisporum was found throughout the plant, in roots as well as in stems and leaves. Whereas V. dahliae in 67% of the cases only was present in the root and lower stem. To investigate the host specificity of V. longisporum, seven species, both crops and weeds were inoculated with three isolates (VD2, VD4 and G1-11). Brassica napus, Sinapis arvensis and Matricaria inodora were found to be highly susceptible to the pathogen, but microsclerotia could also be re-isolated from Triticum aestivum and Avena sativa. In Swedish soils the density of microsclerotia ranged from 1 to 48 cfu/g soil, causing between 4 and 72% of disease incidence in the fields. However, no direct correlation could be found between microsclerotia density and disease incidence. A regression analysis showed that the yield of the winter oilseed rape crop could be predicted by using three variables: percentage Verticillium wilt diseased plants, temperature in May and temperature in September. The early plant defence response in Arabidopsis thaliana towards V. longisporum is dependent on ethylene and jasmonic acid. Increased ethylene production is also important for later symptom development, such as wilting and chlorosis. Six mutants were found to be susceptible to V. longisporum: ein4-1, ein2-1, ein6-1, ndr1-1 npr1-1 and rfo1-1. RFO1 is a wall-associated-receptor-like protein, found to confer resistance to V. longisporum similar as earlier found to Fusarium oxysporum.

Authors/Creators:Johansson, Anna
Title:Verticillium longisporum, infection, host range, prevalence and plant defence responses
Year of publishing :May 2006
Number of Pages:27
ALLI. Zhou L., Hu Q., Johansson A., Dixelius C. 2006. Verticillium longisporum and V. dahliae: infection and disease in Brassica napus. Plant Pathology 55, 137-144. II. Johansson A., Goud J.K.C., Dixelius C. 2006. Plant host range of Verticillium longisporum and detection of microsclerotia in Swedish soils. European Journal of Plant Pathology 114, 139-149. III. Johansson A., Staal J., Dixelius C. 2006. Early responses in the Arabidopsis – Verticillium longisporum pathosystem are dependent on NDR1, JA/ET-associated signals via cytosolic NPR1 and RFO1. Molecular Plant-Microbe Interaction (Accepted).
Place of Publication:Uppsala
ISBN for printed version:91-576-7153-2
Publication Type:Licentiate thesis
Full Text Status:Public
Agrovoc terms:brassicaceae, oil crops, arabidopsis thaliana, verticillium, pathogens, fungal diseases, wilts, host pathogen relations, infection, defence mechanisms, ethylene
Keywords:Arabidopsis thaliana, ethylene, host specificity, microsclerotia, oilseed crops, RFO1
Permanent URL:
ID Code:1119
Department:(NL, NJ) > Dept. of Plant Biology and Forest Genetics (until 131231)
Deposited By: Anna Johansson
Deposited On:17 May 2006 00:00
Metadata Last Modified:02 Dec 2014 10:09

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