Docking of acetyl-CoA carboxylase to the plastid envelope membrane attenuates fatty acid production in plants
In plants, light-dependent activation of de novo fatty acid synthesis
(FAS) is partially mediated by acetyl-CoA carboxylase (ACCase), the
first committed step for this pathway. However, it is not fully
understood how plants control light-dependent FAS regulation to meet the
cellular demand for acyl chains.
We report here the identification of a gene family encoding for three
small plastidial proteins of the envelope membrane that interact with
the ╬?-carboxyltransferase (╬?-CT) subunit of ACCase and participate in an
original mechanism restraining FAS in the light.
Light enhances the interaction between carboxyltransferase interactors
(CTIs) and ╬?-CT, which in turn attenuates carbon flux into FAS.
Knockouts for CTI exhibit higher rates of FAS and marked increase in
absolute triacylglycerol levels in leaves, more than 4-fold higher than
in wild-type plants. Furthermore,┬áWRINKLED1, a master transcriptional
regulator of FAS, positively regulates/CTI1/expression by direct binding
to its promoter.
This study reveals that in addition to light-dependent activation,
Ô??envelope dockingÔ?Ł of ACCase permits fine-tuning of fatty acid supply
during the plant life cycle.
Docking of acetyl-CoA carboxylase to the plastid envelope membrane
attenuates fatty acid production in plants | Nature Communications