title: Fluorescence resonance energy transfer-sensitized emission of yellow cameleon 3.60 reveals root zone-specific calcium signatures in Arabidopsis in response to aluminum and other trivalent cations.
abstract: Fluorescence resonance energy transfer-sensitized emission of the yellow cameleon 3.60 was used to study the dynamics of cytoplasmic calcium ([Ca(2+)](cyt)) in different zones of living Arabidopsis (Arabidopsis thaliana) roots. Transient elevations of [Ca(2+)](cyt) were observed in response to glutamic acid (Glu), ATP, and aluminum (Al(3+)). Each chemical induced a [Ca(2+)](cyt) signature that differed among the three treatments in regard to the onset, duration, and shape of the response. Glu and ATP triggered patterns of [Ca(2+)](cyt) increases that were similar among the different root zones, whereas Al(3+) evoked [Ca(2+)](cyt) transients that had monophasic and biphasic shapes, most notably in the root transition zone. The Al(3+)-induced [Ca(2+)](cyt) increases generally started in the maturation zone and propagated toward the cap, while the earliest [Ca(2+)](cyt) response after Glu or ATP treatment occurred in an area that encompassed the meristem and elongation zone. The biphasic [Ca(2+)](cyt) signature resulting from Al(3+) treatment originated mostly from cortical cells located at 300 to 500 mu m from the root tip, which could be triggered in part through ligand-gated Glu receptors. Lanthanum and gadolinium, cations commonly used as Ca(2+) channel blockers, elicited [Ca(2+)](cyt) responses similar to those induced by Al(3+). The trivalent ion-induced [Ca(2+)](cyt) signatures in roots of an Al(3+)-resistant and an Al(3+)-sensitive mutant were similar to those of wild-type plants, indicating that the early [Ca(2+)](cyt) changes we report here may not be tightly linked to Al(3+) toxicity but rather to a general response to trivalent cations.
authors.affiliation: Department of Biology, College of Science and Mathematics, Midwestern State University, Wichita Falls, Texas 76308, USA. eblancaflor@noble.org
authors.forename: Magaly
authors.initials: M
authors.lastname: Rincón-Zachary
authors.forename: Neal D
authors.initials: ND
authors.lastname: Teaster
authors.forename: J Alan
authors.initials: JA
authors.lastname: Sparks
authors.forename: Aline H
authors.initials: AH
authors.lastname: Valster
authors.forename: Christy M
authors.initials: CM
authors.lastname: Motes
authors.forename: Elison B
authors.initials: EB
authors.lastname: Blancaflor
mesh_terms: D000535:Aluminum / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D005456:Fluorescent Dyes / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D018613:Microscopy, Confocal; D018517:Plant Roots / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism
chemical_list: D002135:Calcium-Binding Proteins; D005456:Fluorescent Dyes; C495639:yellow cameleon; D018698:Glutamic Acid; D000535:Aluminum; D002118:Calcium