Mitochondrial fatty acid β-oxidation is required for storage-lipid catabolism in a marine diatom

© 2020 The Authors. New Phytologist © 2020 New Phytologist Trust..

Photoautotrophic growth in nature requires the accumulation of energy-containing molecules via photosynthesis during daylight to fuel nighttime catabolism. Many diatoms store photosynthate as the neutral lipid triacylglycerol (TAG). While the pathways of diatom fatty acid and TAG synthesis appear to be well conserved with plants, the pathways of TAG catabolism and downstream fatty acid β-oxidation have not been characterised in diatoms. We identified a putative mitochondria-targeted, bacterial-type acyl-CoA dehydrogenase (PtMACAD1) that is present in Stramenopile and Hacrobian eukaryotes, but not found in plants, animals or fungi. Gene knockout, protein-YFP tags and physiological assays were used to determine PtMACAD1's role in the diatom Phaeodactylum tricornutum. PtMACAD1 is located in the mitochondria. Absence of PtMACAD1 led to no consumption of TAG at night and slower growth in light : dark cycles compared with wild-type. Accumulation of transcripts encoding peroxisomal-based β-oxidation did not change in response to day : night cycles or to PtMACAD1 knockout. Mutants also hyperaccumulated TAG after the amelioration of N limitation. We conclude that diatoms utilise mitochondrial β-oxidation; this is in stark contrast to the peroxisomal-based pathways observed in plants and green algae. We infer that this pattern is caused by retention of catabolic pathways from the host during plastid secondary endosymbiosis.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:228

Enthalten in:

The New phytologist - 228(2020), 3 vom: 15. Nov., Seite 946-958

Sprache:

Englisch

Beteiligte Personen:

Jallet, Denis [VerfasserIn]
Xing, Denghui [VerfasserIn]
Hughes, Alexander [VerfasserIn]
Moosburner, Mark [VerfasserIn]
Simmons, Mark P [VerfasserIn]
Allen, Andrew E [VerfasserIn]
Peers, Graham [VerfasserIn]

Links:

Volltext

Themen:

β-oxidation
Biofuel
Diatom
Fatty Acids
Journal Article
Lipid
Lipids
Phaeodactylum tricornutum
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Anmerkungen:

Date Completed 14.05.2021

Date Revised 14.05.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1111/nph.16744

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM311150535