Research focusing on model plants has underpinned the recent growth in plant genomics and genetics and provided a basis for investigations of major crop species. In the legume family Fabaceae, groundbreaking genetic and genomic research has established a significant body of knowledge on Lotus japonicus, which was adopted as a model species more than 20 years ago. The diverse nature of legumes means that such research has a wide potential and agricultural impact, for example, on the world’s protein production.