title: Insights into the regulation of DMSP synthesis in the diatom Thalassiosira pseudonana through APR activity, proteomics and gene expression analyses on cells acclimating to changes in salinity, light and nitrogen.
abstract: Despite the importance of dimethylsulphoniopropionate (DMSP) in the global sulphur cycle and climate regulation, the biological pathways underpinning its synthesis in marine phytoplankton remain poorly understood. The intracellular concentration of DMSP increases with increased salinity, increased light intensity and nitrogen starvation in the diatom Thalassiosira pseudonana. We used these conditions to investigate DMSP synthesis at the cellular level via analysis of enzyme activity, gene expression and proteome comparison. The activity of the key sulphur assimilatory enzyme, adenosine 5'-phosphosulphate reductase was not coordinated with increasing intracellular DMSP concentration. Under all three treatments coordination in the expression of sulphur assimilation genes was limited to increases in sulphite reductase transcripts. Similarly, proteomic 2D gel analysis only revealed an increase in phosphoenolpyruvate carboxylase following increases in DMSP concentration. Our findings suggest that increased sulphur assimilation might not be required for increased DMSP synthesis, instead the availability of carbon and nitrogen substrates may be important in the regulation of this pathway. This contrasts with the regulation of sulphur metabolism in higher plants, which generally involves up-regulation of several sulphur assimilatory enzymes. In T. pseudonana changes relating to sulphur metabolism were specific to the individual treatments and, given that little coordination was seen in transcript and protein responses across the three growth conditions, different patterns of regulation might be responsible for the increase in DMSP concentration seen under each treatment.
authors.affiliation: Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom; John Innes Centre, Norwich, United Kingdom.
authors.forename: Nicola Louise
authors.initials: NL
authors.lastname: Kettles
authors.affiliation: John Innes Centre, Norwich, United Kingdom.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Kopriva
authors.affiliation: Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom.
authors.forename: Gill
authors.initials: G
authors.lastname: Malin
mesh_terms: D000064:Acclimatization / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D017377:Diatoms / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000528:radiation effects; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000528:radiation effects; D008027:Light; D008715:Methionine / Q000378:metabolism; D009584:Nitrogen / Q000494:pharmacology*; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000378:metabolism*; D010788:Photosynthesis / Q000187:drug effects; D020543:Proteome / Q000378:metabolism; D040901:Proteomics; D054712:Salinity; D013431:Sulfates / Q000378:metabolism; D013452:Sulfonium Compounds / Q000378:metabolism*; D013455:Sulfur / Q000378:metabolism
chemical_list: D020543:Proteome; D013431:Sulfates; D013452:Sulfonium Compounds; D013455:Sulfur; D008715:Methionine; C068078:dimethylpropiothetin; D050862:Oxidoreductases Acting on Sulfur Group Donors; C019618:adenylylsulfate reductase; D009584:Nitrogen
references.citation: Planta. 1980 Jan;150(2):158-65
references.pmid: 24306591
references.citation: Nature. 1997 Jun 26;387(6636):891-4
references.pmid: 9202120
references.citation: Plant Cell Physiol. 2001 Feb;42(2):121-8
references.pmid: 11230565
references.citation: Plant J. 2002 Sep;31(6):729-40
references.pmid: 12220264
references.citation: Plant J. 1999 Oct;20(1):37-44
references.pmid: 10571863
references.citation: Plant Physiol. 2012 Jan;158(1):299-312
references.pmid: 22065419
references.citation: Photochem Photobiol. 2000 Oct;72(4):508-12
references.pmid: 11045722
references.citation: Annu Rev Plant Biol. 2011;62:157-84
references.pmid: 21370978
references.citation: Plant Physiol. 2000 Jul;123(3):1087-96
references.pmid: 10889258
references.citation: J Biol Chem. 2007 Aug 3;282(31):22930-8
references.pmid: 17519237
references.citation: Genome Biol. 2002 Jun 18;3(7):RESEARCH0034
references.pmid: 12184808
references.citation: Plant J. 2000 May;22(4):335-43
references.pmid: 10849350
references.citation: PLoS One. 2013 Oct 16;8(10):e75653
references.pmid: 24146769
references.citation: J Bacteriol. 1998 Mar;180(6):1586-91
references.pmid: 9515933
references.citation: Plant Physiol. 2000 Mar;122(3):737-46
references.pmid: 10712537
references.citation: Biochemistry. 2001 Jul 31;40(30):9040-8
references.pmid: 11467967
references.citation: Plant Sci. 2011 Apr;180(4):575-83
references.pmid: 21421406
references.citation: Science. 2004 Oct 1;306(5693):79-86
references.pmid: 15459382
references.citation: Anal Biochem. 1976 May 7;72:248-54
references.pmid: 942051
references.citation: J Biol Chem. 2000 Jul 21;275(29):22196-201
references.pmid: 10896953
references.citation: Nature. 2002 Jul 18;418(6895):317-20
references.pmid: 12124622
references.citation: Plant Physiol. 2008 Oct;148(2):1055-67
references.pmid: 18753283
references.citation: Plant Physiol. 1991 Sep;97(1):253-8
references.pmid: 16668378
references.citation: Plant Physiol. 2008 Mar;146(3):1408-20
references.pmid: 18218969
references.citation: Plant Physiol. 2002 Nov;130(3):1406-13
references.pmid: 12428005
references.citation: J Exp Bot. 2004 Aug;55(404):1799-808
references.pmid: 15234989
references.citation: J Biol Chem. 2003 Feb 14;278(7):4932-42
references.pmid: 12466265
references.citation: Aquat Microb Ecol. 2009 Jun 3;55(3):241-253
references.pmid: 19829762
references.citation: Nucleic Acids Res. 2001 May 1;29(9):e45
references.pmid: 11328886
references.citation: Biochem Soc Trans. 2006 Apr;34(Pt 2):330-3
references.pmid: 16545107
references.citation: Curr Biol. 1993 Jun 1;3(6):327-32
references.pmid: 15335725
references.citation: Plant Physiol. 2011 Dec;157(4):1926-41
references.pmid: 22034629
references.citation: Proteins. 2009 Feb 1;74(2):368-77
references.pmid: 18623062
references.citation: New Phytol. 2013 Aug;199(3):650-62
references.pmid: 23692606
references.citation: FEBS J. 2005 Feb;272(4):892-902
references.pmid: 15691324
references.citation: Plant Cell Physiol. 2002 Dec;43(12):1493-501
references.pmid: 12514246
references.citation: Geobiology. 2011 Jul;9(4):301-12
references.pmid: 21627761
references.citation: J Biol Chem. 1962 Jul;237:2251-4
references.pmid: 13901535
references.citation: Plant Cell. 2010 Apr;22(4):1216-31
references.pmid: 20424176
references.citation: Biochemistry. 2002 Dec 3;41(48):14391-402
references.pmid: 12450406