Mechanical interaction between hyphae during three-dimensional growth.

The microscopic development of a mycelium is of importance in all aspects of fungal biology and biotechnology. However, the mechanics of three-dimensional (3D) hyphal growth has been not explored. Using light-sheet fluorescence microscopy, we follow the 3D growth of Trichoderma atroviride in liquid medium and observe two direct collision events among hyphae. In both cases, a hypha undergoing tip extension collides with the side of another hypha, causing mechanical deformation that remains after the collision. From these data we estimate that the force developed by hyphae during tip elongation is at least 260 pN.