Phosphorus nutrition and root-associated fungal microbiota of nonmycorrhizal Arabis alpina

Associations with mycorrhizal fungi greatly enhance phosphorus (P) uptake for most plants, but the Brassicaceae are nonmycorrhizal due to the loss of essential symbiosis genes. Almario et al. investigated the fungal microbiota of Arabis alpina, a Brassicaceae species that grows in very-low P soils. The authors identified fungi of the Helotiales order that are strongly associated with roots in P-deficient conditions and which, when re-introduced into sterilized soil, enhanced P-uptake by the plants including the transfer of inorganic P from fungus to plant. As compared to related strains, this newly identified plant-beneficial endophyte shows an expansion of genes encoding carbohydrate-active enzymes (CAZymes), similar to that seen in mycorrhizal species. Proc. Natl. Acad. Sci. USA   10.1073/pnas.1710455114