Previously we showed that luminous fungi share a common mechanism in bioluminescence [1], and identified hispidin as a luciferin precursor in Vietnamese Neonothopanus nambi mycelium [2]. In luminous mycelium, hispidin is converted to 3-hydroxyhispidin and then oxidized to caffeylpyruvic acid. Light emission occurs during this oxidization process and the produced caffeylpyruvic acid is readily hydrolyzed to caffeic acid [3].

In this study, we showed the presence of hispidin as a bioluminescent active compound at 25-1,000 pmol/g in the fruiting body of the Japanese Mycena chlorophos, Omphalotus japonicus, and the Brazilian Neonothopanus gardneri. We also found that cell-free fruiting body extract of luminous mushroom M. chlorophos gradually emits the light by the addition of hispidin biosynthetic components, namely caffeic acid, ATP and malonyl-CoA [3]. These findings suggest that continuous weak glow of luminous mushroom is regulated by slow recycling biosynthesis of hispidin.

[1] Purtov et al. (2015) Angew. Chem. Int. Ed. 54, 8124-8128.

[2] Kaskova et al. (2017) Sci. Adv. 3, e1602847.

[3] Oba et al. (2017) Photochem. Photobiol. Sci. 16, 1435-1440.