Anaerobic endosymbiont generates energy for ciliate host by denitrification

Jon S. Graf (), Sina Schorn, Katharina Kitzinger, Soeren Ahmerkamp, Christian Woehle, Bruno Huettel, Carsten J. Schubert, Marcel M. M. Kuypers and Jana Milucka ()
Additional contact information
Jon S. Graf: Max Planck Institute for Marine Microbiology
Sina Schorn: Max Planck Institute for Marine Microbiology
Katharina Kitzinger: Max Planck Institute for Marine Microbiology
Soeren Ahmerkamp: Max Planck Institute for Marine Microbiology
Christian Woehle: Max Planck Institute for Plant Breeding Research
Bruno Huettel: Max Planck Institute for Plant Breeding Research
Carsten J. Schubert: Eawag
Marcel M. M. Kuypers: Max Planck Institute for Marine Microbiology
Jana Milucka: Max Planck Institute for Marine Microbiology

Nature, 2021, vol. 591, issue 7850, 445-450

Abstract: Abstract Mitochondria are specialized eukaryotic organelles that have a dedicated function in oxygen respiration and energy production. They evolved about 2 billion years ago from a free-living bacterial ancestor (probably an alphaproteobacterium), in a process known as endosymbiosis1,2. Many unicellular eukaryotes have since adapted to life in anoxic habitats and their mitochondria have undergone further reductive evolution3. As a result, obligate anaerobic eukaryotes with mitochondrial remnants derive their energy mostly from fermentation4. Here we describe ‘Candidatus Azoamicus ciliaticola’, which is an obligate endosymbiont of an anaerobic ciliate and has a dedicated role in respiration and providing energy for its eukaryotic host. ‘Candidatus A. ciliaticola’ contains a highly reduced 0.29-Mb genome that encodes core genes for central information processing, the electron transport chain, a truncated tricarboxylic acid cycle, ATP generation and iron–sulfur cluster biosynthesis. The genome encodes a respiratory denitrification pathway instead of aerobic terminal oxidases, which enables its host to breathe nitrate instead of oxygen. ‘Candidatus A. ciliaticola’ and its ciliate host represent an example of a symbiosis that is based on the transfer of energy in the form of ATP, rather than nutrition. This discovery raises the possibility that eukaryotes with mitochondrial remnants may secondarily acquire energy-providing endosymbionts to complement or replace functions of their mitochondria.

Date: 2021
References: Add references at CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.nature.com/articles/s41586-021-03297-6 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:591:y:2021:i:7850:d:10.1038_s41586-021-03297-6

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/s41586-021-03297-6

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().