Calcium signaling in plant-microbe interaction
Introduction
Calcium ion (Ca2+) is an important second messenger involved in many signaling pathways in plants.[1] The concentration of free Ca2+ in the cytosol in a plant cell ([Ca2+]cyt) connects the extracellular stimuli, including the signal of microbes, to intracellular responses. Since Ca2+ is neither synthesized nor degraded by plants, [Ca2+]cytis completely dependent on the entry of external source or release of Ca2+ from its intracellular stores.[2][3] However, because Ca2+ can react with phosphate, the energy source of life, its presence in the cytoplasm will prevent energy metabolism and other cellular activities from taking place.[4] Thus, its concentration is regulated tightly by various proteins. In plant-microbe interaction, different microbes trigger different receptor proteins, causing distinctive Ca2+ elevation patterns, referred to as Ca2+ signature. Ca2+ signature can be different from each other in various aspects: amplitude, duration, frequency, spatial distribution, and times of cycle in [Ca2+]cytchanges. The Ca2+ signature produced by microbe signal can be decoded by downstream effectors, changing the expression of defense or symbiosis-related genes, resulting in different responses by plants.[5]
Detection of Microbes
The first step of a Ca2+ signaling event is the detection of microbes performed by pattern-recognition receptors (PRRs), a type of receptor protein located on the plasma membrane of a plant cell. PRRs are capable of recognizing microbe-associated molecular patterns (MAMPs), molecules specific to certain classes of microbes that are present in extracellular space.Cite error: Closing </ref>
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tag One example of these PRRs is flagellin-sensitive 2 (FLS2), which recognizes the flagellin protein in bacteria flagellum.[6] MAMPs of symbiotic bacteria can also be recognized by PPRs. A lysin-motif (LysM) receptor-like kinase, nodulation (nod) factor perception (NFP), can recognize lipochitooligosaccharide in the nod factor released by symbiotic bacteria such as rhizobia.<ref>Gough, Clare and Jacquet Christophe. “Nod factor perception protein carries weight in biotic interactions” 2013. Trends in Plant Science 18(10): 566-574
Formation of Calcium Signature
Decoding of Calcium Signature
Conclusion
References
- ↑ Sanders et al. “Calcium at the Crossroads of Signaling” 2002. The Plant Cell 14:401–S417.
- ↑ Vadassery, J. and Oelmüller, R. “Calcium signaling in pathogenic and beneficial plant microbe interactions” 2009. Plant Signaling & Behavior 4:1024-1027.
- ↑ Edel, Kai H. et al. “The Evolution of Calcium-Based Signalling in Plants” 2017. Current Biology 27(13):R667-R679.
- ↑ Carafoli E. , Krebs J. “Why calcium? How calcium became the best communicator” 2016. Journal of Biological Chemistry 291(40):20849–57.
- ↑ Yuan et al. “Calcium signatures and signaling events orchestrate plant–microbe interactions” 2017. Current Opinion in Plant Biology 38:173-183.
- ↑ Chinchilla, D. et al. “A flagellin-induced complex of the receptor FLS2 and BAK1 initiates plant defence” 2007. Nature 448: 497-500
Edited by Yueqi Song, student of Joan Slonczewski for BIOL 116 Information in Living Systems, 2021, Kenyon College.