Energetic coupling between plastids and mitochondria drives CO2 assimilation in diatoms

Nature. 2015 Aug 20;524(7565):366-9. doi: 10.1038/nature14599. Epub 2015 Jul 13.

Abstract

Diatoms are one of the most ecologically successful classes of photosynthetic marine eukaryotes in the contemporary oceans. Over the past 30 million years, they have helped to moderate Earth's climate by absorbing carbon dioxide from the atmosphere, sequestering it via the biological carbon pump and ultimately burying organic carbon in the lithosphere. The proportion of planetary primary production by diatoms in the modern oceans is roughly equivalent to that of terrestrial rainforests. In photosynthesis, the efficient conversion of carbon dioxide into organic matter requires a tight control of the ATP/NADPH ratio which, in other photosynthetic organisms, relies principally on a range of plastid-localized ATP generating processes. Here we show that diatoms regulate ATP/NADPH through extensive energetic exchanges between plastids and mitochondria. This interaction comprises the re-routing of reducing power generated in the plastid towards mitochondria and the import of mitochondrial ATP into the plastid, and is mandatory for optimized carbon fixation and growth. We propose that the process may have contributed to the ecological success of diatoms in the ocean.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Aquatic Organisms / cytology
  • Aquatic Organisms / enzymology
  • Aquatic Organisms / genetics
  • Aquatic Organisms / metabolism*
  • Carbon Cycle
  • Carbon Dioxide / metabolism*
  • Diatoms / cytology*
  • Diatoms / enzymology
  • Diatoms / genetics
  • Diatoms / metabolism*
  • Ecosystem
  • Mitochondria / metabolism*
  • Mitochondrial Proteins / deficiency
  • Mitochondrial Proteins / metabolism
  • NADP / metabolism
  • Oceans and Seas
  • Oxidation-Reduction
  • Oxidoreductases / deficiency
  • Oxidoreductases / metabolism
  • Phenotype
  • Photosynthesis*
  • Plant Proteins / metabolism
  • Plastids / metabolism*
  • Proton-Motive Force*

Substances

  • Mitochondrial Proteins
  • Plant Proteins
  • Carbon Dioxide
  • NADP
  • Adenosine Triphosphate
  • Oxidoreductases
  • alternative oxidase