How bioluminescent fungi have evolved, retained or lost their luciferase cluster have been revealed by a team of scientists led by Biodiversity Research Center, Academia Sinica Taiwan.

When you venture out in the midst of forests during the summer season in Taiwan, you will be awestruck in what you see; in addition to fireflies, certain wild mushrooms can be spotted glowing under the trees! Why mushrooms glow – display bioluminescence – has always been a curious question for evolutionary biologists.

Dr. Isheng Jason Tsai, Dr. Huei-Mien Ke’s Biodiversity Research Center and colleagues sequenced the genomes of five bonnet mushroom (Mycena) species the genomes in the Mycenoid lineage, which is one of the three major light emitting fungal lineages in Taiwan. The Mycenoid lineage contains about 600 species, but only 11% of them are luminescent. By comparing the bioluminescent and non-bioluminescent mushroom genomes, the team estimated that the world’s first bioluminescent mushroom would have appeared in the Jurassic period, 160 million years ago, using fossils and data analysis. This was followed by the Cretaceous (about 140 million years ago), when the Mycenoid lineage diverged, coinciding with the appearance of large numbers of flowering plants on Earth. The team also hypothesized that, in the Lesser Cretaceous, the emergence of a variety of habitats or nutrient sources provided by these plants would have facilitated the adaptation of Mycenoid species to decompose and coexist with different plant materials.

The luciferase cluster of the Mycenoid lineage were clustered at highly dynamic genome positions and have been rearranged through the process of evolution, resulting in the elimination of some of the luminescence genes of the mushroom clade. The reason why Mycenoid mushrooms still exist is that the bioluminescence might help to adapt to the environment, e.g., attracting insects to eat and spreading spores through the luminescence. The team also identified 54 genes that were associated with luminescence intensity at different developmental stages and tissues which may play a role in regulating the luminescence. Further understanding of its regulation will help us understand the ecological significance of fungal regulation of luminescence.

Understanding the evolution of bioluminescence in fungi is an important step towards understanding the ecology of fungi as well as developing applications such as cell live imaging or glowing plants.

This study was supported by the Ministry of Science and Technology, Taiwan, and the Career Development Award of Academia Sinica.

The study was published online in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) on December 8th, 2020.

Mycena genomes resolve the evolution of fungal bioluminescence