Combination of the Elevated Stearic Acid Trait with Other Fatty Acid Traits in Soybean

Abstract

AbstractStearic acid is one of five major fatty acids found in soybean oil. It is a fully saturated lipid and is known for neutral or positive effects on LDL cholesterol when consumed by humans. Unfortunately, stearic acid only accounts for about 4% of the total seed oil produced in commodity soybean. Previous work has shown that stearic acid can reach levels as high as 28% of the total oil fraction when the SACPD‐C gene, encoding the delta‐9‐stearoyl‐acyl carrier protein desaturase responsible for most of the stearic acid variation in soybean seed, is ablated in combination with other loci. In order to increase stearic acid content and create soybeans with improved utility based on fatty acid composition, we combined mutations in SACPD‐C with other mutations in the fatty acid biosynthetic pathway. Soybean plants carrying mutant alleles of both SACPD‐C and FAD2‐1A produce seed with stearic acid levels from 14% to 21%, and with elevated levels of oleic acid. Soybeans carrying mutations in both SACPD‐C and FAD3A or FAD3C have both statistically significantly elevated levels of stearic acid (from 15–21%) and statistically reduced linolenic acid levels. Neither mutant combination appears to affect other agronomic properties such as plant morphology or seed protein levels making this a potentially viable trait.