New Alleles of FAD3A Lower the Linolenic Acid Content of Soybean Seeds

Abstract

Soybean [Glycine max (L.) Merr.] is one of the most important sources of plant‐based oil worldwide. Linolenic acid is associated with undesirable flavors and poor stability in soybean oil. Partial hydrogenation is typically used to reduce the levels of linolenic acid in soybean oil; however, this process results in the production of trans fatty acids. Studies have shown a link between increased risk of coronary heart disease and trans fatty acids present in hydrogenated oils. Thus, it is crucial to seek out genetic strategies to develop soybean lines with lower linolenic acid. To identify novel and useful alleles that could help reduce levels of linolenic acid in soybean, we screened a chemically mutagenized population. Three lines with reduced levels of linolenic acid in seed were identified. Mutant lines contained 3.8 to 4.5% of the total fatty acids as linolenic acid and carried independent mutations in the FAD3A gene encoding a desaturase responsible for the conversion of linoleic acid to linolenic acid in soybean seeds. To track the mutant alleles in a segregating population, allele specific markers were developed and the genetic association was confirmed with the reduced level of linolenic acid. These soybean lines will serve as a source of reduced linolenic acid to meet the breeding objectives of providing improved soybean lines.