Microinjection of Urediospore Germlings of Uromyces appendiculatus

Corrêa, A., Jr., and Hoch, H. C. 1993. Microinjection of urediospore germlings of Uromyces appendiculatus. Experimental Mycology 17, 253-273. Urediospore germlings of Uromyces appendiculatus were microinjected with a variety of materials to assess the applicability of microinjection methodologies for studying fungal cell growth and development. Until now, hyphal cells have not been successfully microinjected without first being pretreated with osmotica to lower the turgor pressures of the cells. We describe the development of a hydraulicly actuated system and protocols for successfully microinjecting Uromyces cells on a routine basis. Synthetic fluorocarbon and silicone fluids, various fluorophore-conjugated dextrans, rhodamine-conjugated phalloidin, rhodamine 123, cyclic AMP, and cytochalasin E were all microinjected into living urediospore germlings that grew or responded in ways consistent with expected pharmacological effects of the injected material. Germlings that were microinjected with synthetic fluids maintained the ability to sense and respond to inductive topographies for the formation of appressoria. Materials were injected at volumes of ≤0.5 to ≤400 fl. The results of this investigation indicate that fungal cells can be successfully microinjected with a variety of materials and, importantly, continue to function as normal cells.