Are fairy chemicals a new family of plant hormones?

2-Azahypoxanthine (AHX, 1) and imidazole-4-carboxamide (ICA, 2) were isolated from a fairy-ring-forming fungus Lepista sordida. AHX was converted into a metabolite 2-aza-8-oxo-hypoxanthine (AOH, 3) in plants. It was found out that these three compounds, named as fairy chemicals (FCs), endogenously exist in plants and are biosynthesized via a new purine metabolic pathway. FCs provided tolerance to the plants against various stresses and regulated the growth of all the plants. In addition, FCs increased the yield of rice, wheat, and other crops in the greenhouse and/or field experiments.