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Genes, hormones and signalling pathways implicated in plant defence to Leptosphaeria maculans

Kaliff, Maria (2007). Genes, hormones and signalling pathways implicated in plant defence to Leptosphaeria maculans. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2007:119
ISBN 978-91-85913-18-3
[Doctoral thesis]

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Leptosphaeria maculans (anamorph: Phoma lingam) is a hemibiotrophic loculoascomycetous fungus which causes blackleg, a serious disease of Brassica oilseed crops. In order to examine the genetics of resistance to this disease and important signalling pathways, extensive studies on L. maculans interactions with Arabidopsis were carried out. Two resistance loci, RLM1Col and RLM2Ler, have been identified due to transgressive segregation in F2 progenies from the resistant accessions Col-0 and Ler-0. RLM1Col encodes a TIR-NB-LRR resistance gene and confers specific resistance towards L. maculans, while a third R-gene RLM3 confers resistance to L. maculans, Alternaria brassicae, A. brassicicola and Botrytis cinerea. RLM1 is furthermore independent from signalling components, such as SGT1, previously associated to all TIR-NB-LRR resistance genes. In addition to these susceptible genotypes, EMS mutants (lms1 to lms11) susceptible to the pathogen have been assessed in order to facilitate identification of the mechanisms required for resistance. The lms5 mutant has been shown to be specifically susceptible to L. maculans and have altered auxin signalling. During a mapping approach lms5 was found to most likely code for an F-box protein indicating involvement in protein turnover via the ubiquitine proteasome. This result together with mutants involved in protein degradation complexes indicates the importance of protein stability. In contrast to the other pathogens, the defence responses against L. maculans are independent of the phytohormones salicylic acid (SA), jasmonic acid (JA) and ethylene (ET), while abscisic acid (ABA) and auxin, and the phytoalexin camalexin play more crucial roles. Resistance to L. maculans can furthermore be primed by ABA and β-aminobutyric acid (BABA) treatments. This priming results in increased callose deposition in a resistance gene-dependent manner. The callose deposition is furthermore regulated by PR2. Moreover comparative studies with B. napus have been undertaken, confirming that the Arabidopsis-L. maculans pathosystem can be used as a model for the B. napus - L. maculans interaction. Taken together, this work ontributes to increase our knowledge about the Arabidopsis – L. maculans pathosystem.

Authors/Creators:Kaliff, Maria
Title:Genes, hormones and signalling pathways implicated in plant defence to Leptosphaeria maculans
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2007
Number of Pages:58
ALLI. Staal, J., Kaliff, M., Bohman, S. and Dixelius, C. (2006) Transgressive segregation reveals two Arabidopsis TIR-NB-LRR resistance genes effective against Leptosphaeria maculans, causal agent of blackleg disease. The Plant Journal, 46, 218-230. II. §Kaliff, M., §Staal, J., Myrenås, M. and Dixelius, C. (2007) ABA is required for Leptosphaeria maculans resistance via ABI1 and ABI4 dependent signalling. Molecular Plant-Microbe Interaction, 20, 335-345. III. Kaliff, M., Oide, S., Staal, J. and Dixelius, C. (2007) An ABA dependent repression of beta-glucanase enhance callose deposition in the Arabidopsis-Leptosphaeria maculans pathosystem. (In manuscript) IV. Kaliff, M. and Dixelius, C. (2007) lms5, a mutant with dual roles in auxin and Arabidopsis – Leptosphaeria maculans defence signalling. (In manuscript) § indicates shared first authorship
Place of Publication:Uppsala
ISBN for printed version:978-91-85913-18-3
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:leptosphaeria maculans, fungal diseases, plant diseases, erwinia carotovora, bacterioses, arabidopsis thaliana, brassica napus, defence mechanisms, genetic resistance, loci, auxins, aba
Keywords:ABA, Arabidopsis thaliana, Auxin, Blackleg, Callose, Defence signalling, Hormones, Phoma lingam, R-genes
Permanent URL:
ID Code:1653
Department:(NL, NJ) > Dept. of Plant Biology and Forest Genetics (until 131231)
Deposited By: Maria Kaliff
Deposited On:10 Dec 2007 00:00
Metadata Last Modified:02 Dec 2014 10:13

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