Reef coral fluorescent proteins for visualizing fungal pathogens.

The fluorescent proteins AmCyan, ZsGreen, ZsYellow, and AsRed, modified versions of proteins identified recently from several Anthozoa species of reef corals, were expressed for the first time in a heterologous system and used for imaging two different fungal plant pathogens. When driven by strong constitutive fungal promotors, expression of these reef coral fluorescent proteins yielded bright cytoplasmic fluorescence in Fusarium verticillioides and Magnaporthe grisea, and had no detectable effect on either growth rate or the ability to cause disease. Differential intracellular localization of the fluorescent proteins resulted in the discrimination of many subcellular organelles by confocal and multi-photon microscopy, and facilitated monitoring of such details as organelle dynamics and changes in the permeability of the nuclear envelope. AmCyan and ZsGreen were sufficiently excited at 855 and 880 nm, respectively, to allow for time-resolved in planta imaging by two-photon microscopy.