CRISPR/Cas9-Mediated Knockout of Significantly Reduced the Amount of Saturated Fatty Acids in Soybean Seeds.

Soybean () oil is one of the most widely used vegetable oils across the world. Breeding of soybean to reduce the saturated fatty acid (FA) content, which is linked to cardiovascular disease, would be of great significance for nutritional improvement. Acyl-acyl carrier protein thioesterases (FATs) can release free FAs and acyl-ACP, which ultimately affects the FA profile. In this study, we identified a pair of soybean FATB coding genes, and . Mutants that knock out either or both of the genes were obtained via CRISPR/Cas9. Single mutants, and , showed a decrease in leaf palmitic and stearic acid contents, ranging from 11% to 21%. The double mutant, , had a 42% and 35% decrease in palmitic and stearic acid content, displayed growth defects, and were male sterility. Analysis of the seed oil profile revealed that and had significant lower palmitic and stearic acid contents, 39-53% and 17-37%, respectively, while that of the unsaturated FAs were the same. The relative content of the beneficial FA, linoleic acid, was increased by 1.3-3.6%. The oil profile changes in these mutants were confirmed for four generations. Overall, our data illustrate that knockout mutants have great potential in improving the soybean oil quality for human health.