Calcium signaling in pathogenic and beneficial plant microbe interactions: what can we learn from the interaction between Piriformospora indica and Arabidopsis thaliana
Volume 4, Issue 11
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Pages 1024 - 1027http://dx.doi.org/10.4161/psb.4.11.9800
Authors: Jyothilakshmi Vadassery and Ralf Oelmüller View affiliations
Elevation of intracellular calcium levels in a plant cell is an early signaling event in many mutualistic and pathogenic plant/microbe interactions. In pathogenic plant/fungus interactions, receptor-mediated cytoplasmic calcium elevations induce defense genes via the activation of ion fluxes at the plasma membrane, an oxidative burst and MAPK activation. Mycorrhizal and beneficial endophytic plant/fungus interactions result in a better plant performance through sequencial cytoplasmic and nuclear calcium elevations. The specificity of the calcium responses depends on the calcium signature, its amplitude, duration, frequency and location, a selective activation of calcium channels in the diverse cellular membranes and the stimulation of calcium-dependent signaling components. Arabidopsis contains more than 100 genes for calcium-binding proteins and channels and the response to pathogens and beneficial fungi relies on a highly specific activation of individual members of these protein families. Genetic tools are required to understand this complex response patterns and the cross talks between the individual calcium-dependent signaling pathways. The beneficial interaction of Arabidopsis with the growth-promoting endophyte Piriformospora indica provides a nice model system to unravel signaling events leading to mutualistic or pathogenic plant/fungus interactions.
Received: August 10, 2009; Accepted: August 12, 2009