CRISPR/Cas9-mediated mutagenesis of SEED FATTY ACID REDUCER genes significantly increased seed oil content in soybean.

Increasing seed oil content (SOC) is an important breeding goal for soybean breeding. While significant efforts have been made to improve SOC through metabolic pathway engineering, research to increase soybean SOC by reducing lipid degradation and fatty acid (FA) decomposition during seed maturation process is limited. Seed fatty acid reducers (SFARs) are members of the GDSL enzyme family and play a crucial role in lipid metabolism. Among them, a pair of the GmSFAR4 genes is highly expressed in soybean seeds during seed desiccation and germination. In the study, GmSFAR4a/b double mutants were generated using CRISPR/Cas9-mediated gene editing technique. The seed FA content of GmSFAR4a/b double mutants was significantly increased by ∼8% compared to wild type when grown in greenhouse, and ∼17% when grown in the field, without any adverse effects on seed vitality and plant growth. Our work enriches the understanding of soybean seed oil metabolism and provides a new approach to increase soybean SOC.