title: Antisense knockdown of pyruvate dehydrogenase kinase promotes the neutral lipid accumulation in the diatom Phaeodactylum tricornutum.
abstract: BACKGROUND
  Microalgae have been an emerging biofuel resource; however, the germplasm improvement has been slow due to the lack of molecular tools. Pyruvate dehydrogenase kinase (PDK) deactivates the pyruvate dehydrogenase complex (PDC) which catalyzes the oxidative decarboxylation of pyruvate. Acetyl-CoA production via PDC is important in plant tissues that are active in fatty acid synthesis.
  
  
  RESULTS
  A 1261-bp cDNA of a putative PDK gene (PtPDK) was cloned from a diatom Phaeodactylum tricornutum, and PtPDK antisense knockdown transgenic diatoms were generated. Both PtPDK transcript abundance and enzyme activity were reduced significantly due to antisense knockdown of PtPDK. Neutral lipid content of transgenic diatom cells increased up to 82% as determined by Nile red staining, and fatty acid composition was not altered. Transgenic cells showed slightly lower growth rate but similar cell size with the wild type, hence retaining similar biomass productivity.
  
  
  CONCLUSIONS
  This work first obtained a successful engineered diatom regulating a key gene involved in lipid metabolism. Our findings also provide powerful indications in enhancing microalgal lipid production by metabolic engineering for biofuel industry.
authors.forename: Yu-Han
authors.initials: YH
authors.lastname: Ma
authors.forename: Xiang
authors.initials: X
authors.lastname: Wang
authors.forename: Ying-Fang
authors.initials: YF
authors.lastname: Niu
authors.forename: Zhi-Kai
authors.initials: ZK
authors.lastname: Yang
authors.forename: Meng-Han
authors.initials: MH
authors.lastname: Zhang
authors.forename: Zhong-Ming
authors.initials: ZM
authors.lastname: Wang
authors.forename: Wei-Dong
authors.initials: WD
authors.lastname: Yang
authors.forename: Jie-Sheng
authors.initials: JS
authors.lastname: Liu
authors.forename: Hong-Ye
authors.initials: HY
authors.lastname: Li
mesh_terms: D017377:Diatoms / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D055785:Gene Knockdown Techniques; D050356:Lipid Metabolism; D060847:Metabolic Engineering; D058086:Microalgae / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D016372:RNA, Antisense / Q000235:genetics / Q000378:metabolism
chemical_list: D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D016372:RNA, Antisense; D017346:Protein Serine-Threonine Kinases
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