title: Calcium impacts carbon and nitrogen balance in the filamentous cyanobacterium Anabaena sp. PCC 7120.
abstract: Calcium is integral to the perception, communication and adjustment of cellular responses to environmental changes. However, the role of Ca(2+) in fine-tuning cellular responses of wild-type cyanobacteria under favourable growth conditions has not been examined. In this study, extracellular Ca(2+) has been altered, and changes in the whole transcriptome of Anabaena sp. PCC 7120 have been evaluated under conditions replete of carbon and combined nitrogen. Ca(2+) induced differential expression of many genes driving primary cellular metabolism, with transcriptional regulation of carbon- and nitrogen-related processes responding with opposing trends. However, physiological effects of these transcriptional responses on biomass accumulation, biomass composition, and photosynthetic activity over the 24h period following Ca(2+) adjustment were found to be minor. It is well known that intracellular carbon:nitrogen balance is integral to optimal cell growth and that Ca(2+) plays an important role in the response of heterocystous cyanobacteria to combined-nitrogen deprivation. This work adds to the current knowledge by demonstrating a signalling role of Ca(2+) for making sensitive transcriptional adjustments required for optimal growth under non-limiting conditions.
authors.affiliation: Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland.
authors.forename: Julia
authors.initials: J
authors.lastname: Walter
authors.affiliation: Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland.
authors.forename: Fiona
authors.initials: F
authors.lastname: Lynch
authors.affiliation: Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland.
authors.forename: Natalia
authors.initials: N
authors.lastname: Battchikova
authors.affiliation: Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland.
authors.forename: Eva-Mari
authors.initials: EM
authors.lastname: Aro
authors.affiliation: Department of Biochemistry, Molecular Plant Biology, University of Turku, FI-20014 Turku, Finland peter.gollan@utu.fi.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Gollan
mesh_terms: D017033:Anabaena / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D015398:Signal Transduction; D059467:Transcriptome
chemical_list: D002244:Carbon; D009584:Nitrogen; D002118:Calcium
keywords: Anabaena; bicarbonate; calcium; cmpA; cyanobacteria; nirA; nitrogen; transcriptomics.