Accelerated organelle movements can indirectly affect the motility of other organelles in plant cells.

Abstract

Organelle movements in plants are driven by myosin XI motors moving along the actin filament cytoskeleton. Several experiments suggested that indirect effects such as organelle-organelle interactions or hydrodynamic flow may be responsible for organelle movements. To test these models, we altered the motile behavior of specific organelles in Nicotiana benthamiana leaf epidermal cells and examined the effects of these perturbations on other organelles. Recruiting myosins to organelles with "Booster" constructs resulted in significant increases of linear motions, while binding organelles to cortical microtubules with "Anchor" constructs lead to diminished movements of the targeted mitochondria, peroxisomes and ER, respectively. We did not observe consistent effects of Anchor constructs on non-targeted organelles. Mitochondrial Boosters increased the motility of all tested organelles, presumably by leading to a reorganization of actin filaments. By contrast, ER Boosters resulted in enhanced movements only of Golgi stacks and peroxisomes, suggesting a specific interaction between these organelles. Collectively, this novel engineering approach to modify the movements of specific organelles demonstrates that organelle motility in plant cells can occur independently but nevertheless is coordinated between different types of organelles.