title: Proteogenomics of a saxitoxin-producing and non-toxic strain of Anabaena circinalis (cyanobacteria) in response to extracellular NaCl and phosphate depletion.
abstract: In Australia, saxitoxin production is strain dependent within the bloom-forming freshwater cyanobacterium Anabaena circinalis. Freshwater cyanobacteria are exposed to rapid fluctuations in environmental nutrient concentrations, and their adaption is vital for competition, succession and dominance. Two elements of environmental significance, phosphorus and sodium chloride, are proposed to play a role in bloom development and saxitoxin biosynthesis respectively. The aim of our study was to comparatively analyse the model saxitoxin-producing A. circinalis AWQC131C and non-toxic A. circinalis AWQC310F at the genomic level and proteomic level, in response to phosphate depletion and increased extracellular NaCl. When challenged, photosynthesis, carbon/nitrogen metabolisms, transcription/translation, oxidative stress and nutrient transport functional categories demonstrated the largest changes in protein abundance. In response to increased NaCl, SxtC, a protein conserved in all known saxitoxin biosynthetic pathways, was downregulated. Additionally, toxin quantification revealed a decrease in total saxitoxin and decarbomoyl-gonyautoxin2/3 content in response to the NaCl treatment. In response to phosphate depletion, the toxic and non-toxic strain displayed similar proteomic profiles, although the toxic strain did not alter the abundance of as many proteins as the non-toxic strain. These findings have important implications for the future, since response and adaption mechanisms are directly related to in situ dominance of cyanobacteria.
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, NSW 2052, Australia.|School of Science and Health, Western Sydney University, Campbelltown, NSW 2560, Australia.
authors.forename: Paul M
authors.identifier: http://orcid.org/0000-0002-8323-5416
authors.initials: PM
authors.lastname: D'Agostino
authors.affiliation: Australian Proteomics Analysis Facility, Macquarie University, Macquarie Park, NSW 2109, Australia.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Song
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, NSW 2052, Australia.
authors.forename: Brett A
authors.initials: BA
authors.lastname: Neilan
authors.affiliation: School of Science and Health, Western Sydney University, Campbelltown, NSW 2560, Australia.
authors.forename: Michelle C
authors.initials: MC
authors.lastname: Moffitt
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D017033:Anabaena / Q000235:genetics / Q000378:metabolism*; D001315:Australia; D001483:Base Sequence; D053898:Biosynthetic Pathways / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D016678:Genome; D023281:Genomics; D057097:Harmful Algal Bloom; D008969:Molecular Sequence Data; D010710:Phosphates / Q000172:deficiency*; D010788:Photosynthesis / Q000235:genetics; D040901:Proteomics; D012530:Saxitoxin / Q000096:biosynthesis*; D017422:Sequence Analysis, DNA; D012965:Sodium Chloride / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D010710:Phosphates; D012530:Saxitoxin; D012965:Sodium Chloride