REGULATOR OF FATTY ACID SYNTHESIS proteins regulate de novo fatty acid synthesis by modulating hetACCase distribution

Area of Science:

• Plant Biology
• Biochemistry
• Molecular Biology

Background:

• Heteromeric acetyl-CoA carboxylase (hetACCase) is crucial for de novo fatty acid synthesis (FAS) in plants.
• Precise regulation of hetACCase is essential for meeting cellular demands for acyl chains throughout the plant life cycle.

Purpose of the Study:

• To systematically analyze the coexpression of hetACCase and its regulators in Arabidopsis thaliana.
• To elucidate the regulatory mechanism governing hetACCase activity and de novo FAS.

Main Methods:

• Coexpression analysis in Arabidopsis thaliana.
• CRISPR/Cas9 gene editing to create knockout mutants.
• Confocal microscopy for colocalization studies.
• Biochemical assays to measure hetACCase activity and fatty acid content.

Main Results:

• Identified REGULATOR OF FATTY ACID SYNTHESIS 1 (RFS1) with expression positively correlated to other hetACCase regulators.
• RFS1 colocalizes and directly interacts with CARBOXYLTRANSFERASE INTERACTOR 1 (CTI1).
• RFS and CTI knockouts show enhanced hetACCase activity, increased FAS rates, and higher triacylglycerol accumulation in leaves.
• Mutations alter plastid membrane distribution of α-CT, reducing membrane-bound hetACCase activity.

Conclusions:

• Revealed a novel regulatory module involving RFS proteins in controlling de novo fatty acid synthesis.
• Identified a genetic locus with potential for improving oil crops through targeted breeding strategies.