Wj. Drost et al., Identification of a mutant fatty acid elongase allele from zero-percent erucic acid Sinapis alba, THEOR A GEN, 103(5), 2001, pp. 752-757
The fae1 gene codes for KCS (beta -keto-acyl-CoA synthase), the candidate e
nzyme for elongation of oleic acid to eicosenoic acid and erucic acid (C22:
1) in various oilseed species. Degenerate primers for the fae1 gene were us
ed to amplify and clone fae1 gene homologs in high and zero C22:1 Sinapis a
lba. Under stringent PCR conditions, a polymorphism was revealed between th
e two genotypes and was mapped as a fae1 marker in an F-2 population derive
d from a cross between high and zero C22:1 S. alba. The fae1 marker co-segr
egated with C22:1 content and the C22:1 phenotypic locus. In addition, a se
t of 11 RAPD markers for C22:1 in S. alba was identified. Cloning and seque
ncing of the fae1 alleles in high and zero C22:1 S. alba revealed two amino
-acid substitutions specific to zero C22:1 S. alba. The underlying nucleoti
de substitution for one of the amino-acid substitutions and an adjacent sil
ent nucleotide substitution were used to design primers for allele-specific
amplicons for both the wild-type and zero C22:1 alleles. The two diagnosti
c PCR tests are reliable selection tools to identify S. alba carrying one o
r both of the wild-type and mutant C22:1 alleles of the KCS gene.