View source for Physics:Calcium signaling in Arabidopsis

{{DISPLAYTITLE:Calcium signaling in ''Arabidopsis''}}
[[File:Arabidopsis thaliana kz08.jpg|thumb|330x330px|''[[Biology:Arabidopsis thaliana|Arabidopsis thaliana]]'']]
'''Calcium signaling in ''Arabidopsis''''' is a [[Biology:Calcium in biology|calcium]] mediated signalling pathway that ''[[Biology:Arabidopsis|Arabidopsis]]'' plants use in order to respond to a stimuli. In this pathway, Ca<sup>2+</sup> works as a long range communication ion, allowing for rapid communication throughout the plant. Systemic changes in [[Biology:Metabolite|metabolite]]s such as [[Chemistry:Glucose|glucose]] and [[Chemistry:Sucrose|sucrose]] takes a few minutes after the [[Biology:Stimulus (physiology)|stimulus]], but [[Biology:Gene|gene]] [[Biology:Transcription|transcription]] occurs within seconds.<ref name="Johns_2021">{{cite journal | vauthors = Johns S, Hagihara T, Toyota M, Gilroy S | title = The fast and the furious: rapid long-range signaling in plants | journal = Plant Physiology | volume = 185 | issue = 3 | pages = 694–706 | date = April 2021 | pmid = 33793939 | doi = 10.1093/plphys/kiaa098 | pmc = 8133610 }}</ref> Because [[Biology:Hormone|hormone]]s, [[Chemistry:Peptide|peptide]]s and [[Biology:RNA|RNA]] travel through the vascular system at lower speeds than the plants response to wounds, indicates that [[Biology:Calcium in biology|Ca<sup>2+</sup>]] must be involved in the rapid signal propagation.<ref name="Johns_2021" /> Instead of local communication to nearby [[Biology:Cell|cells]] and tissues, Ca<sup>2+</sup> uses [[Physics:Mass flow (life sciences)|mass flow]] within the vascular system to help with rapid transport throughout the [[Biology:Plant|plant]]. Ca<sup>2+</sup> moving through the [[Biology:Xylem|xylem]] and [[Biology:Phloem|phloem]] acts through a “calcium signature” [[Biology:Receptor (biochemistry)|receptor]] system in cells where they integrate the signal and respond with the activation of defense genes.<ref name="Savatin_2014">{{cite journal | vauthors = Savatin DV, Gramegna G, Modesti V, Cervone F | title = Wounding in the plant tissue: the defense of a dangerous passage | journal = Frontiers in Plant Science | volume = 5 | pages = 470 | date = 2014 | pmid = 25278948 | pmc = 4165286 | doi = 10.3389/fpls.2014.00470 | doi-access = free }}</ref> These calcium signatures encode information about the stimulus allowing the response of the plant to cater towards the type of stimulus.

== Calcium wound/damage response ==
Different kinds of stimuli result in different responses within the ''[[Biology:Arabidopsis|Arabidopsis]]'' plant. A [[Medicine:Wound|wound]] or damage to the plant causes a wound-activated surface potential (WASP) changes that serve as an alert message to undamaged tissues. This wound response results in a [[Biology:Cell membrane|plasma membrane]] [[Biology:Depolarization|depolarization]], [[Chemistry:Hydron|H+]] and Ca<sup>2+</sup> efflux and K+ influx, causing an [[Biology:Action potential|action potential]]. This action potential causes Ca<sup>2+</sup> cytosolic concentration to increase, therefore sending calcium into the phloem, where the signaling is spread, and as it arrives to systemic tissues. Because of the various stimuli perceived by the plant, abiotic and [[Biology:Biotic stress|biotic stress]] results in different [[Physics:Amplitude|amplitude]]s, durations, [[Physics:Frequency|frequencies]] and localizations of Ca<sup>2+</sup> concentrations. These “calcium signatures” encode information about the nature of the stimulus and different signatures are sensed by different sensor [[Biology:Protein|protein]]s.<ref name="Savatin_2014" /> With herbivory being an abiotic stressor, Ca<sup>2+</sup> is sensed by the regulatory [[Biology:Ubiquitin|ubiquitin]] protein [[Biology:Calmodulin|calmodulin]], which [[Biology:Phosphorylation|phosphorylates]] JAV1. In turn, it ubiquitinates JAV1 so it no longer inhibits the [[Biology:Biosynthesis|biosynthesis]] of JA, giving a rapid increase of the JA hormone. This increase signals the defense system to begin transcribing JA inducible defense genes against herbivory.<ref>{{cite journal | vauthors = Yan C, Fan M, Yang M, Zhao J, Zhang W, Su Y, Xiao L, Deng H, Xie D | display-authors = 6 | title = Injury Activates Ca<sup>2+</sup>/Calmodulin-Dependent Phosphorylation of JAV1-JAZ8-WRKY51 Complex for Jasmonate Biosynthesis | journal = Molecular Cell | volume = 70 | issue = 1 | pages = 136–149.e7 | date = April 2018 | pmid = 29625034 | doi = 10.1016/j.molcel.2018.03.013 | doi-access = free }}</ref> Alert messages are generated and propagated throughout the plant to undamaged tissues through WASPs, Ca<sup>2+</sup>, and hormonal signals, such as JA.<ref name="Savatin_2014" />

== Calcium cold response ==
When an ''Arabidopsis'' plant is subjected to cold temperatures, it induces cold response genes. In order for cold genes to be expressed, COLD1 receptors that are present on the plants surface sense the cold temperature and activate [[Biology:Calcium channel|Ca<sup>2+</sup> channels]], these channels include: MCA1, MCA2 and other undetermined channels. The activation of Ca<sup>2+</sup> channels allows for Ca<sup>2+</sup> to move into the cell and increase cellular Ca<sup>2+</sup> [[Chemistry:Concentration|concentration]].<ref name="Yuan_2018">{{cite journal | vauthors = Yuan P, Yang T, Poovaiah BW | title = Calcium Signaling-Mediated Plant Response to Cold Stress | journal = International Journal of Molecular Sciences | volume = 19 | issue = 12 | pages = 3896 | date = December 2018 | pmid = 30563125 | doi = 10.3390/ijms19123896 | pmc = 6320992 | doi-access = free }}</ref> The concentration and duration of Ca<sup>2+</sup> within the cell is determined by the plants [[Biology:Acclimatization|acclimation]] to the temperature, as well as the [[Physics:Intensity|intensity]] and length of cold duration.<ref name="Zarka_2003">{{cite journal | vauthors = Zarka DG, Vogel JT, Cook D, Thomashow MF | title = Cold induction of Arabidopsis CBF genes involves multiple ICE (inducer of CBF expression) promoter elements and a cold-regulatory circuit that is desensitized by low temperature | journal = Plant Physiology | volume = 133 | issue = 2 | pages = 910–918 | date = October 2003 | pmid = 14500791 | pmc = 219064 | doi = 10.1104/pp.103.027169 }}</ref> During increased Ca<sup>2+</sup> concentrations, Ca<sup>2+</sup> is used as a [[Biology:Second messenger system|second messenger]] to increase the concentration of Ca<sup>2+</sup> dependent protein kinase ([[Biology:Cyclin-dependent kinase|CPKs]]). During times of increased Ca<sup>2+</sup> concentrations, Ca<sup>2+</sup> also binds to calmodulin on the CRLK and AtSR1/CAMTA3. Activation of the CRLK causes an [[Biology:Mitogen-activated protein kinase|MAPK cascade]] that activates the MAPK pathway, signaling for the suppression of ICE1 degradation: ICE1 encodes a [[Biology:Transcription factor|transcription factor]] that promotes production of CBF/DREB genes.<ref name="Zarka_2003" /> AtSR1 also binds to the [[Biology:Promoter (genetics)|promoter]] region of CBF and promotes CBF gene expression.<ref name="Yuan_2018" /> CBF and DREB transcription proteins are then synthesized and bind to the promoter of cold induced genes DRE and [[Biology:CRT (genetics)|CRT]].<ref>{{cite journal | vauthors = Chinnusamy V, Ohta M, Kanrar S, Lee BH, Hong X, Agarwal M, Zhu JK | title = ICE1: a regulator of cold-induced transcriptome and freezing tolerance in Arabidopsis | journal = Genes & Development | volume = 17 | issue = 8 | pages = 1043–1054 | date = April 2003 | pmid = 12672693 | pmc = 196034 | doi = 10.1101/gad.1077503 }}</ref> Binding to the promoter region of the cold induced genes increases the rate of transcription of cold genes, allowing the ''Arabidopsis'' plant to become more acclimated to the cold. This Ca<sup>2+</sup> signaling cascade, and transcription of cold genes in response to cold temperatures, allows for the plants survival.

== References ==
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[[Category:Arabidopsis]]
[[Category:Calcium channels]]
[[Category:Ions]]
[[Category:Stimulants]]

{{Sourceattribution|Calcium signaling in Arabidopsis}}