The ant-plant Hirtella physophora (Chrysobalanaceae), the ant Allomerus decemarticulatus (Myrmicinae) and an Ascomycete fungus, Trimmatostroma sp., form a tripartite association. The fungus improves nutrient uptake by the host plant, but hitherto it has been unclear whether it has an indirect or a direct role in transferring nutrients to the plant.
Identification of hyphae inside stem tissue and a stable nitrogen isotope tracer experiment combined with NanoSIMS imaging reveals that 15N-enriched cells are not diffuse. Leroy et al. show that in this ant-plant system a fungus actively transfers nitrogen from a 15N-labelling solution to the plant’s stem tissues, suggesting that the fungus may play a role in transporting nutrient-derived ant waste. The complex trophic structure of ant-plant interactions is shown to rely upon the presence of the fungus. The study provides insight into the potentially important nutritional aspects and tradeoffs involved in myrmecophyte–ant mutualisms.
Leroy, C., Jauneau, A., Martinez, Y., Cabin-Flaman, A., Gibouin, D., Orivel, J., & Séjalon-Delmas, N. (2017). Exploring fungus–plant N transfer in a tripartite ant–plant–fungus mutualism. Annals of Botany, 120(3), 417–426. https://doi.org/10.1093/aob/mcx064