Updated project metadata. Mitochondria are essential organelles in eukaryotes for energy production and are composed by a double-layered membrane structure that contains a smooth mitochondrial outer membrane (MOM) and a highly invaginated mitochondrial inner membrane (MIM). Mitochondria are dynamic with the ability to fuse and divide, constantly forming changing tubular networks in most eukaryotic cells. However, how mitochondria fusion occurs and functions in plants remains unclear. Here, we identified SAV as an outer membrane mitochondrial component mediates mitochondria fusion and is involved in plant development in Arabidopsis.