Turgor-dependent and coronin-mediated F-actin dynamics drive septin disc-to-ring remodeling in the blast fungus Magnaporthe oryzae
by Dulal, N.; Rogers, A. M.; Proko, R.; Bieger, B. D.; Liyanage, R.; Krishnamurthi, V. R.; Wang, Y.; Egan, M. J.
The fungus Magnaporthe oryzae uses a specialized pressure-generating infection cell called an appressorium to break into rice leaves and initiate disease. Appressorium functionality is dependent on the formation of a cortical septin ring during its morphogenesis, but precisely how this structure assembles is unclear. Here, we show that F-actin rings are recruited to the circumference of incipient septin disc-like structures in a pressure-dependent manner, and that this is necessary for their contraction and remodeling into rings. We demonstrate that the structural integrity of these incipient septin discs requires both an intact F-actin and microtubule cytoskeleton and provide fundamental new insight into their functional organization within the appressorium. Lastly, using proximity-dependent labeling, we identify the actin modulator coronin as a septin-proximal protein and show that F-actin-mediated septin disc-to-ring remodeling is perturbed in the genetic absence of coronin. Taken together, our findings provide new insight into the dynamic remodeling of infection-specific higher-order septin structures in a globally significant fungal plant pathogen.
- Journal
- Journal of Cell Science
- Volume
- 134
- Issue
- 5
- Year
- 2021
- URL
- https://dx.doi.org/10.1242/jcs.251298
- ISBN/ISSN
- 1477-9137; 0021-9533
- DOI
- 10.1242/jcs.251298