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BMC Genet. 2014 Aug 29;15:94. doi: 10.1186/s12863-014-0094-7.

Development and characterization of low α-linolenic acid Brassica oleracea lines bearing a novel mutation in a 'class a' FATTY ACID DESATURASE 3 gene.

Author information

1
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton T6G 2P5, Alberta, Canada. Habibur.rahman@ualberta.ca.

Abstract

BACKGROUND:

Traditional canola (Brassica napus L.; AACC, 2n=38) cultivars yield seed oil with a relatively high proportion of α-linolenic acid (ALA; C18:3cis∆9,12,15), which is desirable from a health perspective. Unfortunately, due to the instability of this fatty acid, elevated levels also result in oils that exhibit a short shelf life and problems associated with use at high temperatures. As a result, the development of cultivars bearing reduced amounts of ALA in their seeds is becoming a priority. To date, several low ALA B. napus cultivars (~2-3% ALA of total fatty acids) have been developed and molecular analyses have revealed that the low ALA phenotype of lines tested thus far is a result of mutations within two 'class b' FATTY ACID DESATURASE 3 (FAD3) genes. Since B. napus possesses six FAD3 genes (two 'class a', two 'class b' and two 'class c') and ALA levels of approximately 2-3% remain in these low ALA lines, it is likely that the mutation of additional FAD3 genes could further decrease the content of this fatty acid.

RESULTS:

In this study, we generated low ALA (≤2%) lines of B. oleracea, which is the C genome progenitor species of B. napus, via ethyl methanesulphonate (EMS) mutagenesis. We identified a novel nonsense mutation within the 'class a' FAD3 gene (BoFAD3-2) in these lines, which would result in the production of an encoded protein lacking 110 amino acids at its C terminus. When expressed in Saccharomyces cerevisiae, this mutant protein exhibited a drastic decline in its Δ-15 desaturase activity compared to the wild-type (wt) protein. Furthermore, we demonstrated that the expression of the mutant BoFAD3-2 gene was significantly reduced in developing seeds of low ALA lines when compared to expression in wt plants.

CONCLUSIONS:

Given the additive nature of FAD3 mutations on ALA content and the ease with which B. napus can be re-synthesized from its progenitor species, the mutant isolated here has the potential to be used for the future development of B. napus cultivars exhibiting further reductions in ALA content.

PMID:
25167929
PMCID:
PMC4236532
DOI:
10.1186/s12863-014-0094-7
[Indexed for MEDLINE]
Free PMC Article

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