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bioRxiv · 10.64898/2026.01.27.701996

Quantification of Aspergillus nidulans Actin Dynamics during Early Growth and Septum Formation

Huso, W.·Hill, G.·Tarimala, G.·Lee, J.·Doan, A. G.·Gray, K. J.·Edwards, H.·Harris, S.·Marten, M. R.
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Abstract

Filamentous fungi have complex, three-dimensional growth patterns and a non-adherent nature, which can present challenges for live-cell imaging for quantitative assessment of dynamic cellular processes. To address these challenges, a live-cell imaging system has been modified to constrain the model fungus Aspergillus nidulans to growth in a single focal plane. This enables high-resolution time-lapse imaging of actin dynamics throughout development using a Lifeact actin marker. This system was used to perform kymographic analysis to quantify actin velocity and hyphal extension rates during early hyphal development. Results show two distinct growth phases: germ tube extension (0.58 m/min) and hyphal extension (1.52 m/min). Actin exhibited bi-directional transport along hyphae with biased movement toward the spore body. Actin was also observed re-localizing from hyphal tips to sites of septum formation indicating active redistribution of cytoskeletal resources based on cellular demands. This technological advancement overcomes longstanding limitations in fungal live-cell imaging and provides a new platform for quantitative systems-level analysis of mycelial development, offering new insights into the spatiotemporal coordination of cytoskeletal dynamics during filamentous growth.

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Huso, W., Hill, G., Tarimala, G., Lee, J., Doan, A. G., Gray, K. J., Edwards, H., Harris, S., Marten, M. R.. 2026-01-28. Quantification of Aspergillus nidulans Actin Dynamics during Early Growth and Septum Formation. https://doi.org/10.64898/2026.01.27.701996

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