- A-Z
- Endocytobiosis and ...
- Volume 27
- Issue 3: Research I...
- Fungi establishing ...
- Autor(in)
- Seitenbereich
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001-005
- Schlagwort(e)
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plant-microbe interaction, calcium, phosphoproteome,
systemic signalling
- Zusammenfsg.
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A huge number of beneficial and pathogenic fungi release biomolecules into the rhizosphere, which initiate signaling events in the roots leading to mutualistic or pathogenic plant/fungus interactions. The combination and concentration of the individual biomolecules in the rhizosphere is critical for the plant´s decision to invest in either growth or defense. These biomolecules activate receptors in the roots and induce cytoplasmic Ca2+ ([Ca2+]cyt) elevation in a phosphorylation-dependent manner. Furthermore, they stimulate phospholipid signaling which coordinate the balanced response between growth/development and defense, by cross talking to the Ca2+ signals. We use transgenic Arabidopsis and tobacco plants expressing the Ca2+ sensor aequorin to isolate and identify biomolecules from the exudates of the beneficial root-colonizing fungi Piriformospora indica and Mortierella hyalina, and from the pathogenic fungi Alternaria brassicae and Verticillium dahliae. The exudate components induce a rapid and transient increase in [Ca2+]cyt levels in the roots. We isolated and characterized the fungal biomolecules responsible for the Ca2+ responses, and Arabidopsis mutants, which do not respond to these biomolecules. While Ca2+ responses are induced by all four fungi, and [Ca2+]cyt elevation is necessary for the proper plant responses to these fungi, production of reactive oxygen species occurs only in response to pathogenic fungi, and in a Ca2+-dependent manner. We study early signaling events in plants (e.g. reversible phosphorylation) in response to exudates from these fungi, as well as systemic signaling, which informs the entire plant body about the presence of a particular fungus. Furthermore, the two beneficial fungi promote plant performance and root and shoot growth, and we identify compounds (genes and metabolites), metabolic and signaling pathways which are involved in root growth promotion and optimal root adaptation to environmental cues. These compounds are currently characterized and tested for their agricultural applications. Finally, we want to know whether microbes are aware of other microbes colonizing the same root, and how root colonization by multiple fungal species affects the microbial community in the rhizosphere.