Resumen

CEDENO, Luis. Easy and reliable method for nuclei staining of Rhizoctonia complex fungi. Bioagro [online]. 2008, vol.20, n.3, pp.215-219. ISSN 1316-3361.

Hyphal morphology and septal structure configuration of the fungi included in Rhizoctonia complex allows for differentiation of genus, while species may be distinguished by nuclear condition and thickness of the runner hyphae, or teleomorph morphometry. For characterization of species in uni, bi, and multinucleate diverse methods of staining have been developed using acridine orange, aniline and trypan blue, diamine phenyl indole (DAPI), giemsa, hematoxiline, orcein and saphranin O. Some of these procedures are quick to perform, while others require special techniques (fluorescence) or are time consuming, which impose a limit on the number of samples that can be processed at a time. A new method of nuclei staining was developed during the analysis of anastomosis groups (AGs) of R. solani strains isolated from potato plants cultivated in Mérida, Venezuela. The procedure is quick, easy, and reliable, and allows for simultaneous manipulation of a significant number of samples, and both nucleus and nucleolus maintain their integrity. The method was successfully assayed in 10 different AGs testers of R. solani, and allowed separation of 173 multinucleate and 3 binucleate Rhizoctonia strains. Method effectiveness depends upon growth medium (water agar 2.4 % plus PDA 0.39 %), culture age (18-48 h), fixing agent (formaldehyde 4 %), and stain (fuchsin acid 0.025 % in lactic acid 50 %).

Palabras clave : Mycology; staining; hyphal morphology; potato.