Researchers Discover Evolutionary Tipping Point in Fungi
Published:23 May2024    Source:New York University
Scientists have found a "tipping point" in the evolution of fungi that throttles their growth and sculpts their shapes. The findings, published in the journal Cell Reports, demonstrate how small changes in environmental factors can lead to huge changes in evolutionary outcomes.
To understand the reasons for different shapes of hyphae, the researchers combined theory and experiments to investigate fungi and water molds from across nature. Surprisingly, the shapes of actual hyphae found in nature assumed only a small subset of the possible shapes. They examined the growth rate of hyphae with different shapes to create a fitness landscape for hyphae. The researchers found that fitness landscapes can be much more rich than a system of peaks and valleys. They predicted that hyphae with shapes near the brink of the tipping point would be particularly vulnerable to small environmental, chemical, or genetic changes.

The researchers tested their prediction by treating fungi near the tipping point with small amounts of chemicals that affected hyphal growth. They used one chemical that reduces pressure within the hyphae and another derived from a sea sponge that blocks the hypha's ability to deliver cellular components to the tip of the cell. Both treatments caused the same dramatic effect: the hyphae elongated much more slowly and with a strange nub shape not found in nature.