title: Ocean acidification modulates expression of genes and physiological performance of a marine diatom.
abstract: Ocean Acidification (OA) is known to affect various aspects of physiological performances of diatoms, but little is known about the underlining molecular mechanisms involved. Here, we show that in the model diatom Phaeodactylum tricornutum, the expression of key genes associated with photosynthetic light harvesting as well as those encoding Rubisco, carbonic anhydrase, NADH dehydrogenase and nitrite reductase, are modulated by OA (1000 μatm, pHnbs 7.83). Growth and photosynthetic carbon fixation were enhanced by elevated CO2. OA treatment decreased the expression of β-carbonic anhydrase (β-ca), which functions in balancing intracellular carbonate chemistry and the CO2 concentrating mechanism (CCM). The expression of the genes encoding fucoxanthin chlorophyll a/c protein (lhcf type (fcp)), mitochondrial ATP synthase (mtATP), ribulose-1, 5-bisphosphate carboxylase/oxygenase large subunit gene (rbcl) and NADH dehydrogenase subunit 2 (ndh2), were down-regulated during the first four days (< 8 generations) after the cells were transferred from LC (cells grown under ambient air condition; 390 μatm; pHnbs 8.19) to OA conditions, with no significant difference between LC and HC treatments with the time elapsed. The expression of nitrite reductase (nir) was up-regulated by the OA treatment. Additionally, the genes for these proteins (NiR, FCP, mtATP synthase, β-CA) showed diel expression patterns. It appeared that the enhanced photosynthetic and growth rates under OA could be attributed to stimulated nitrogen assimilation, increased CO2 availability or saved energy from down-regulation of the CCM and consequently lowered cost of protein synthesis versus that of non-nitrogenous cell components.
authors.affiliation: State Key Laboratory of Marine Environmental Science (Xiamen University), College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors.forename: Yahe
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Marine Environmental Science (Xiamen University), College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors.forename: Shufang
authors.initials: S
authors.lastname: Zhuang
authors.affiliation: State Key Laboratory of Marine Environmental Science (Xiamen University), College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, Jilin University, Changchun, China.
authors.forename: Honglin
authors.initials: H
authors.lastname: Ren
authors.affiliation: State Key Laboratory of Marine Environmental Science (Xiamen University), College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors.forename: Fangyi
authors.initials: F
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Marine Environmental Science (Xiamen University), College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Lin
authors.affiliation: State Key Laboratory of Marine Environmental Science (Xiamen University), College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors.forename: Kejian
authors.initials: K
authors.lastname: Wang
authors.affiliation: School of Biological Sciences, Monash University, Clayton, Victoria, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Beardall
authors.affiliation: State Key Laboratory of Marine Environmental Science (Xiamen University), College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
authors.forename: Kunshan
authors.initials: K
authors.lastname: Gao
mesh_terms: D002244:Carbon / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D002256:Carbonic Anhydrases / Q000235:genetics; D002734:Chlorophyll / Q000378:metabolism; D017377:Diatoms / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D015536:Down-Regulation; D018507:Gene Expression Regulation, Developmental; D006863:Hydrogen-Ion Concentration; D009245:NADH Dehydrogenase / Q000235:genetics; D009572:Nitrite Reductases / Q000235:genetics; D009584:Nitrogen / Q000378:metabolism; D009792:Oceans and Seas; D010788:Photosynthesis / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics; D012623:Seawater / Q000737:chemistry; D013997:Time Factors
chemical_list: D002734:Chlorophyll; D002245:Carbon Dioxide; D002244:Carbon; D009245:NADH Dehydrogenase; D009572:Nitrite Reductases; D012273:Ribulose-Bisphosphate Carboxylase; D002256:Carbonic Anhydrases; D009584:Nitrogen