Alexander Lewis 
Nov 15, 2023
Wageningen University researchers are investigating how filamentous fungi avoid life-limiting mutations despite their age. They propose a hypothesis explaining how these fungi prevent detrimental mutations in their mycelia, the root-like structures of fungal colonies.
Filaments in mushroom-forming fungi consist of two separate nuclei, which combine briefly before spore formation. Mutations in these nuclei hinder filament fusion, burdening neighbouring mycelia for spore production and leading to the dominance of mutated mycelia over time.
This dynamic resembles cancer in other organisms, where mutant cells replicate rapidly, harming the host. These fungal mutations, called "cheaters", act as "nucleus cancers", reducing the organism's overall fitness.
Comparing fast-growing moulds to long-lived mushroom mycelia, researchers suggest that the latter employ a unique cell division process called "clamp connection" to prevent the proliferation of selfish mutants. In this process, one haploid nucleus is held until fusion potential is assessed. Mutations in fusion genes lead to failed fusion tests.
While humans and animals develop cancer due to genetic errors, organisms with longer lifespans possess mechanisms to repair DNA damage, regulate cell division, and suppress cancer.
Although fungi differ from animals, finding particular cellular machinery in fungi to combat human cancer is less likely. The study showcases remarkable evolutionary solutions organisms have developed to maintain life despite self-undermining mechanisms.
