The fungal endophytes: does the rate of mycelium growth decrease with host age and host generations?

Fungal endophyte Epichloë poae shows a decrease in mycelium growth rate with host plant age and successive generations in vitro.

• Why it matters: Understanding factors affecting vertical transmission of endophytes is crucial for predicting their persistence and effectiveness in host plants. The growth rate may influence the endophyte's ability to colonize seeds, impacting transmission success.
• What they did: Researchers passaged fungal mycelium in vitro to simulate vertical transmission, measuring growth rates across different host ages and generations, and comparing isolates from first and second generations.
• The result: Fungal growth rate declined with host age and in successive passages, and differed between isolates from different generations, suggesting growth rate as a potential indicator of endophyte performance in seed colonization.