Title:Genome-wide identification of FAD gene family and functional analysis of MsFAD3.1 involved in the accumulation of α-linolenic acid in alfalfa
Authors:Zhengshe Zhang, Xiaoyu Jin, Zhipeng Liu, jiyu Zhang, Wenxian Liu*
Abstract:As an important forage legume in the world, alfalfa (Medicago sativa L.) has high adaptability to various unfavorable climatic conditions and high biomass, and have been playing critical roles in animal husbandry and industrial applications. As α-linolenic acid cannot be synthesized by animals, and most must be obtained from plants, the increasing of α-linolenic acid content in alfalfa will greatly contribute to improve quality of livestock. However, the molecular mechanisms for α-linolenic acid synthesis and accumulation in alfalfa are still limited. In this study, the importance of ω-3 fatty acid desaturase (FAD) was demonstrated by analyzing α-linolenic acid metabolic pathways, combined with the dynamics of accumulation of unsaturated fatty acids in alfalfa. Moreover, the FAD3.1 identified in alfalfa was located in the endoplasmic reticulum, and its expression level was consistent with the accumulation patterns of α-linolenic acid in leaves. Heterologous expression in yeast cells proves that MsFAD3.1 was involved in the synthesis of α-linolenic acid, and the α-linolenic acid content in MsFAD3.1-overexpression transgenic alfalfa lines was significantly increased. These results indicate that new alfalfa germplasm with high α-linolenic acid content can be successfully created through biotechnology, providing a theoretical basis for further improving the quality of afalfa and the nutritional value of dairy products.