A GmFAD3A mutation in the low linolenic acid soybean mutant C1640

The linolenic acid component is responsible for the flavour and odour instability of soybean oil. Thus, development of low linolenic acid soybean lines has been a major goal in crop science research. One such low linolenic acid soybean line, A5, contains a deletion of the omega-3 fatty acid desaturase gene GmFAD3A. Another low linolenic acid soybean line, C1640, is allelic with A5, suggesting it too contains a mutation in the GmFAD3A gene. The purpose of this work was to characterize the genetic lesion in C1640 using GmFAD3A as a candidate gene. It could be that a premature stop codon is introduced in the gene, presumably rendering a non-functional truncated enzyme. An assay to distinguish between the wild type and mutant alleles by using PCR followed by endonuclease digestion was developed. This assay will aid soybean breeders that are trying to incorporate the C1640 low linolenic acid trait into other lines.