title: Spatial and temporal specificity of Ca2+signalling in Chlamydomonas reinhardtii in response to osmotic stress.
abstract: Ca2+-dependent signalling processes enable plants to perceive and respond to diverse environmental stressors, such as osmotic stress. A clear understanding of the role of spatiotemporal Ca2+signalling in green algal lineages is necessary in order to understand how the Ca2+signalling machinery has evolved in land plants. We used single-cell imaging of Ca2+-responsive fluorescent dyes in the unicellular green alga Chlamydomonas reinhardtii to examine the specificity of spatial and temporal dynamics of Ca2+elevations in the cytosol and flagella in response to salinity and osmotic stress. We found that salt stress induced a single Ca2+elevation that was modulated by the strength of the stimulus and originated in the apex of the cell, spreading as a fast Ca2+wave. By contrast, hypo-osmotic stress induced a series of repetitive Ca2+elevations in the cytosol that were spatially uniform. Hypo-osmotic stimuli also induced Ca2+elevations in the flagella that occurred independently from those in the cytosol. Our results indicate that the requirement for Ca2+signalling in response to osmotic stress is conserved between land plants and green algae, but the distinct spatial and temporal dynamics of osmotic Ca2+elevations in C. reinhardtii suggest important mechanistic differences between the two lineages.
authors: Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK.|Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK.
authors: Peter
authors: P
authors: Bickerton
authors: Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK.|Department of Biology, University of Padova, Via U. Bassi 58/B, 35131, Padova, Italy.
authors: Simone
authors: S
authors: Sello
authors: Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK.|School of Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK.
authors: Colin
authors: C
authors: Brownlee
authors: Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK.
authors: Jon K
authors: JK
authors: Pittman
authors: Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK.
authors: Glen L
authors: GL
authors: Wheeler
mesh_terms: D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects; D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism; D016825:Chlamydomonas reinhardtii / Q000187:drug effects / Q000502:physiology*; D005407:Flagella / Q000187:drug effects / Q000378:metabolism; D040542:Mechanotransduction, Cellular / Q000187:drug effects; D009997:Osmotic Pressure / Q000187:drug effects*; D010802:Phylogeny; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects; D013997:Time Factors
chemical_list: D012965:Sodium Chloride; D002118:Calcium
keywords: 
  Chlamydomonas reinhardtii
  ; calcium; flagella; green algae; osmotic stress; signalling