Ca²⁺ signalling in plant immune response: from pattern recognition receptors to Ca²⁺ decoding mechanisms

Abstract

-dependent phosphorylation events and transcriptional reprogramming. To highlight the complexity of the cellular signal network, we briefly touch on the interplay between Ca 2+ -dependent signalling and selected major signalling mechanisms -with special emphasis on reactive oxygen species at local and systemic levels.

From Chaos to Harmony: Responses and Signaling upon Microbial Pattern Recognition

“…Lines of evidence support that MAMP- triggered [Ca 2+ ] cyt increase comes from a sustained extracellular Ca 2+ influx from the apoplast (138). Chelation of extracellular Ca 2+ or pretreatment with Ca 2+ surrogates abolishes [Ca 2+ ] cyt bursts, especially the first peak(78).…”

“…Perception of MAMPs typically triggers the increase of [Ca 2+ ] cyt with a delay of ~30–40 sec and a peak at ~2–6 min, which then lasts for at least 30 min before declining to the resting state (127). The spatial and temporal changes in [Ca 2+ ] cyt vary in terms of the peak time, amplitude, and duration in response to different types and dosages of MAMPs (138). Cryptogein, flg22, and β-glucan trigger a biphasic [Ca 2+ ] cyt increase, whereas a chitin-induced [Ca 2+ ] cyt burst exhibits only a single peak.…”

“…Mutation in Arabidopsis cyclic nucleotide-gated cation channel 2 (CNGC2) abolishes At PEP3- and LPS- but not flg22-induced [Ca 2+ ] cyt bursts (104). In addition, inhibiting the activity of ionotropic gluta-mate receptor type Ca 2+ channels (iGluRs) blocks cryptogein- and flg22-induced [Ca 2+ ] cyt bursts in tobacco and Arabidopsis (138). Moreover, rice two-pore channel 1 ( Os TPC1) is involved in xylanase-induced [Ca 2+ ] cyt bursts (56).…”

Multiple Calmodulin-binding Sites Positively and Negatively Regulate Arabidopsis CYCLIC NUCLEOTIDE-GATED CHANNEL12

“…Though the importance of Ca 2+ signaling in immunity is well established, the molecular components involved in generating and regulating Ca 2+ signals during defense responses are only beginning to be characterized (Seybold et al, 2014). Furthermore, despite the importance of CNGCs in plant biology, as implied by the expanded size of CNGC gene families and phenotypes of some CNGC mutants, very little is known regarding the structurefunction of these channels.…”

Cellulose-Derived Oligomers Act as Damage-Associated Molecular Patterns and Trigger Defense-Like Responses

“…Plant cell walls are a source of potential defense signaling molecules that can be released 403 upon degradation by pathogen enzymatic repertoires (Hahn et al, 1981;Walton, 1994 (Seybold et al, 2014). While some studies suggest an apoplastic origin of 418 PAMP-induced Ca 2+ influx (Aslam et al, 2008;Ranf et al, 2011;Segonzac et al, 2011), other 419 researchers propose a requirement for intracellular Ca 2+ stores (Ma et al, 2012).…”