Analyse der Genregulation in Medicago truncatula und Pisum sativum während der Entwicklung arbuskulärer Mykorrhiza
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Philipps-Universität Marburg
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Abstract
Arbuscular mycorrhiza (AM) is a symbiotic
interaction between plant roots and soil fungi of the phylum
Glomeromycota, which leads to an improved nutrient supply to
plants, primarily phosphate. Promoter activity of the
proton-pumping ATPase Mtha1 was localised in
arbuscle-containing cortex cells as well as in the fixation
zone and meristeme of nodules in Medicago truncatula roots. The
generated electrochemical gradient could be involved in
nutrient transfer in mycorrhizal and in nodulated roots. A
successful establishment of the AM is associated with a
bidirectional signal exchange between both symbionts.
Phytohormones regulate plant growth and development. Increased
levels of the phytohormones, abscisic acid (ABA) and
indole-3-butyric acid (IBA), in mycorrhizal roots could also
support formation of symbiotic structures. Plant gene
expression is therefore not only altered by AM fungi but also
by secondary effects like changing levels of phytohormones and
phosphate in mycorrhizal root tissue. Investigation of the root
transcriptome of M. truncatula resulted in the identification
of 568 genes, regulated by different AM fungi (Glomus mosseae,
Glomus intraradices, Gigaspora rosea), but not by ABA, IBA or
phosphate. Strong variation of plant gene expression emphasizes
physiological and morphological differences in mycorrhizas,
caused by different AM fungi. Application of suppressive
subtractive hybridisation in combination with macroarray
analysis resulted in the identification of 17 genes in Pisum
sativum induced by mycorrhiza, but not by the symbiont
Sinorhizobium meliloti or by the pathogen Aphanomyces
euteiches. With one exception all genes showed an
arbuscle-associated expression, which could be confirmed for
nine candidates by Nothern blot analysis and semiquantitative
RT-PCR respectively. By sequence comparison of P. sativum genes
with EST databases of M. truncatula a trypsin inhibitor gene
family was found also with transcript accumulation in
mycorrhizal roots, confirmed by Real-Time-PCR. M. truncatula is
therefore a useful model organism for better characterization
of important crop plants like P. sativum.
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Dates
Created: 2004Issued: 2004-06-18Updated: 2011-08-10
Faculty
Fachbereich Biologie
Publisher
Philipps-Universität Marburg
Language
ger
Data types
DoctoralThesis
Keywords
ABA , IBAGene expressionGlomus. GigasporaIBAGlomus. Gigaspora , ABAMycorrhizaMicroarrays
DFG-subjects
MicroarrayWasserstoff-ATPaseMykorrhizaMedicago truncatula , Differentielle Genexpression
DDC-Numbers
570
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Grunwald, Ulf: Analyse der Genregulation in Medicago truncatula und Pisum sativum während der Entwicklung arbuskulärer Mykorrhiza. : Philipps-Universität Marburg 2004-06-18. DOI: https://doi.org/10.17192/z2004.0135.
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This item has been published with the following license: In Copyright