Loline alkaloids: Currencies of mutualism

Increasingly, fungal endophytes are recognized for their roles in plant protection. Several seed-borne endophytes of grasses (Poaceae) produce lolines, which have potent broad-spectrum anti-insect activity. Lolines are structurally unusual pyrrolizidine alkaloids with a strained oxygen bridge. Here the structures, activities, distribution, genetics, biosynthesis and organic synthesis of lolines are reviewed.