title: The SigB σ factor regulates multiple salt acclimation responses of the cyanobacterium Synechocystis sp. PCC 6803.
abstract: Changing of principal σ factor in RNA polymerase holoenzyme to a group 2 σ factor redirects transcription when cyanobacteria acclimate to suboptimal environmental conditions. The group 2 sigma factor SigB was found to be important for the growth of the cyanobacterium Synechocystis sp. PCC 6803 in high-salt (0.7 m NaCl) stress but not in mild heat stress at 43°C although the expression of the sigB gene was similarly highly, but only transiently up-regulated at both conditions. The SigB factor was found to regulate many salt acclimation processes. The amount of glucosylglycerol-phosphate synthase, a key enzyme in the production of the compatible solute glucosylglycerol, was lower in the inactivation strain ΔsigB than in the control strain. Addition of the compatible solute trehalose almost completely restored the growth of the ΔsigB strain at 0.7 m NaCl. High-salt conditions lowered the chlorophyll and phycobilin contents of the cells while protective carotenoid pigments, especially zeaxanthin and myxoxanthophyll, were up-regulated in the control strain. These carotenoids were up-regulated in the ΔsigCDE strain (SigB is the only functional group 2 σ factor) and down-regulated in the ΔsigB strain under standard conditions. In addition, the HspA heat shock protein was less abundant and more abundant in the ΔsigB and ΔsigCDE strains, respectively, than in the control strain in high-salt conditions. Some cellular responses are common to heat and salt stresses, but pretreatment with mild heat did not protect cells against salt shock although protection against heat shock was evident.
authors.affiliation: Department of Biochemistry and Food Chemistry, Molecular Plant Biology, University of Turku, FIN-20014 Turku, Finland.
authors.forename: Hanna-Leena
authors.initials: HL
authors.lastname: Nikkinen
authors.forename: Kaisa
authors.initials: K
authors.lastname: Hakkila
authors.forename: Liisa
authors.initials: L
authors.lastname: Gunnelius
authors.forename: Tuomas
authors.initials: T
authors.lastname: Huokko
authors.forename: Maija
authors.initials: M
authors.lastname: Pollari
authors.forename: Taina
authors.initials: T
authors.lastname: Tyystjärvi
mesh_terms: D000064:Acclimatization; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002338:Carotenoids / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D005960:Glucosides / Q000378:metabolism; D005964:Glucosyltransferases / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism; D018869:Heat-Shock Response; D052980:Phycobilins / Q000378:metabolism; D055049:Salt Tolerance; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*; D046939:Synechocystis / Q000502:physiology*; D014199:Trehalose / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D005960:Glucosides; D006360:Heat-Shock Proteins; C113725:HspA protein, bacteria; D052980:Phycobilins; C079011:SigB protein, Bacteria; D012808:Sigma Factor; C034727:glucosylglycerol; D002734:Chlorophyll; D002338:Carotenoids; D014199:Trehalose; D005964:Glucosyltransferases; C400922:glucosylglycerol-phosphate synthase
references.citation: Microbiology (Reading). 2010 Jan;156(Pt 1):220-229
references.pmid: 19729407
references.citation: Plant Physiol. 2002 Nov;130(3):1443-53
references.pmid: 12428009
references.citation: J Biol Chem. 2011 Feb 4;286(5):3235-41
references.pmid: 21123179
references.citation: Plant Cell Physiol. 2001 Oct;42(10):1140-8
references.pmid: 11673630
references.citation: Biochemistry. 2004 Sep 7;43(35):11321-30
references.pmid: 15366942
references.citation: Arch Microbiol. 1997 Feb-Mar;167(2-3):112-8
references.pmid: 9133317
references.citation: Proteomics. 2006 May;6(9):2733-45
references.pmid: 16572470
references.citation: Plant Physiol. 2005 Jul;138(3):1409-21
references.pmid: 15965020
references.citation: J Bacteriol. 2009 Jun;191(12):3992-4001
references.pmid: 19363110
references.citation: Mol Microbiol. 2007 Jan;63(1):86-102
references.pmid: 17116240
references.citation: Plant Physiol. 2004 Oct;136(2):3290-300
references.pmid: 15361582
references.citation: J Bacteriol. 2003 Feb;185(3):1116-9
references.pmid: 12533490
references.citation: Microbiology (Reading). 2000 Nov;146 ( Pt 11):2877-2889
references.pmid: 11065366
references.citation: Biochim Biophys Acta. 2006 Jul;1757(7):742-9
references.pmid: 16784721
references.citation: Plant Physiol. 1983 Oct;73(2):377-80
references.pmid: 16663223
references.citation: FEMS Microbiol Rev. 2011 Jan;35(1):87-123
references.pmid: 20618868
references.citation: J Biol Chem. 2005 Jun 3;280(22):21531-8
references.pmid: 15805106
references.citation: Plant Physiol. 2008 Aug;147(4):1994-2005
references.pmid: 18539776
references.citation: J Biol Chem. 2004 Dec 17;279(51):53078-86
references.pmid: 15471853
references.citation: FEBS Lett. 2003 Nov 20;554(3):357-62
references.pmid: 14623094
references.citation: FEBS Lett. 2006 Jan 9;580(1):319-23
references.pmid: 16376888
references.citation: Arch Microbiol. 2004 Dec;182(6):487-97
references.pmid: 15483753
references.citation: Plant Physiol. 2000 Apr;122(4):1201-8
references.pmid: 10759516
references.citation: Plant J. 2007 Jan;49(2):313-24
references.pmid: 17181779
references.citation: Plant Cell Physiol. 2010 May;51(5):823-35
references.pmid: 20231245
references.citation: Physiol Plant. 2008 Jul;133(3):490-506
references.pmid: 18331403
references.citation: J Plant Physiol. 2011 Apr 15;168(6):594-600
references.pmid: 21093957
references.citation: Mol Microbiol. 2001 Apr;40(2):476-84
references.pmid: 11309129
references.citation: J Photochem Photobiol B. 2005 Mar 1;78(3):195-201
references.pmid: 15708516
references.citation: Mol Microbiol. 2007 Aug;65(4):936-47
references.pmid: 17617168
references.citation: J Bacteriol. 2002 Jun;184(11):2870-7
references.pmid: 12003926
references.citation: J Bacteriol. 2010 Sep;192(17):4403-12
references.pmid: 20601470
references.citation: Arch Microbiol. 2006 Oct;186(4):273-86
references.pmid: 16868740
references.citation: Microbiology (Reading). 2005 Feb;151(Pt 2):447-455
references.pmid: 15699194
references.citation: Plant Physiol. 2003 Apr;131(4):1628-37
references.pmid: 12692322
references.citation: J Bacteriol. 2011 Jan;193(1):265-73
references.pmid: 20971916
references.citation: Biochem Biophys Res Commun. 2002 Jan 11;290(1):339-48
references.pmid: 11779175