Rapid protocol for visualization of rust fungi structures using fluorochrome Uvitex 2B

Sheshanka Dugyala, Pawel Borowicz, Maricelis Acevedo

Histological examination using fluorochromes is one of the standard methods for observation of microorganisms in tissues and other compartments. In the study of fungi, especially those that cannot be cultured in axenic media such as biotrophic fungi, histological examination of processes associated with the fungal growth, differentiation, infection and other cellular functions can lead to the better understanding of host-parasite interactions. Fluorescence microscopy coupled with Fluorochrome Uvitex 2B have been extensively utilized to study rust fungi structures and host-pathogen interactions. In this study, we report development of a rapid staining protocol of the rust fungus Puccinia triticina using fluorochrome Uvitex 2B. The newly developed rapid procedure was compared with a standard staining technique to observe in planta fungal infection structures development during the wheat-Puccinia triticina interaction. While significantly reducing the time for staining, the rapid protocol described here was equally efficient or better compared to standard procedure in detecting fungal infection structures using Uvitex 2B. In the rapid staining procedure, pre-heating of the stain increased efficiency to detect all the infection structures including haustoria with highly reduced background noise from plant tissue. This staining process described here is simple and quick. It can be completed in 4 h, which is of 6 times faster than the standard Uvitex 2B staining procedure.