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Published on: March 13, 2014
Higher plant cytochrome b5 polypeptides modulate fatty acid desaturation
Rajesh Kumar1, Lam-Son Phan Tran, Anjanasree K Neelakandan
1Division of Plant Sciences and National Center for Soybean Biotechnology, University of Missouri, Columbia, Missouri, United States of America. kraj.pgr@gmail.com
Plos One
|March 3, 2012
Summary
Plant polyunsaturated fatty acid (PUFA) synthesis involves cytochrome b5 (Cb5) isoforms. This study reveals differential Cb5 efficiencies in ω-3 and ω-6 desaturation, impacting PUFA production in plants.
Area of Science:
- Plant Biochemistry
- Molecular Biology
- Lipid Metabolism
Background:
- Polyunsaturated fatty acid (PUFA) synthesis in plants relies on fatty acid desaturases (FADs) and cytochrome b5 (Cb5) as an electron donor.
- Unlike mammals and yeast with a single Cb5, higher plants possess multiple Cb5 isoforms, yet their specific roles in desaturation are poorly understood.
Purpose of the Study:
- To functionally characterize Arabidopsis and soybean Cb5 isoforms.
- To investigate the differential contributions of Cb5 isoforms in ω-3 and ω-6 fatty acid desaturation reactions mediated by FAD2 and FAD3.
Main Methods:
- Functional assays in yeast co-expressing plant Cb5 genes with native or non-native FAD genes.
- Analysis of desaturation product accumulation to assess Cb5 efficiency.
Main Results:
- Arabidopsis Cb5 isoforms exhibited varying efficiencies in ω-6 desaturation, while soybean Cb5 isoforms showed similar efficiencies.
- Specific Cb5 genes in both species facilitated greater ω-3 desaturation product accumulation when co-expressed with FAD3.
- Differential desaturation product accumulation was observed across most Cb5 genes, irrespective of FAD3 origin.
Conclusions:
- This study provides the first evidence of differential Cb5 gene functions in plant fatty acid desaturation.
- The outcome of ω-3/ω-6 desaturation is influenced by the specific Cb5 isoform and the interacting fatty acid desaturases.
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