A user friendly method to isolate and single spore the fungi Magnaporthe oryzae and Magnaporthe grisea obtained from diseased field samples

Authors: Jia, Yulin

Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/2009
Publication Date: 12/15/2009
Citation: Jia, Y. 2009. A user friendly method to isolate and single spore the fungi Magnaporthe oryzae and Magnaporthe grisea obtained from diseased field samples. Plant Health Progress. Available: doi:10.1094/PHP-2009-1215-01-BR.

Interpretive Summary: The fungus Magnaporthe oryzae is the causal agent for a wide range of plant diseases found on rice, wheat, rye grass, turfgrass and pearl millet. A simplified method to systematically isolate spores of the pathogen for use in research was developed. This method does not require elaborate equipment and can successfully generate purified cultures of the pathogen within a few days. Use of this method will help researchers interested in studying plant-pathogen interactions with the goal of improving disease resistance in many of our most important crops.

Technical Abstract: The fungus Magnaporthe oryzae is the causal agent for a wide range of plant diseases including diseases of rice, wheat, rye grass, turfgrass and pearl millet. A simple robust procedure for fungal isolation is not publicly available. In the present study, a user friendly method was developed to isolate the fungus Magnaporthe oryzae from field samples. Leaves with disease symptoms were collected from fields and were incubated in a container with a moistened filter paper under continuous laboratory white fluorescence light using a flow hood. After incubation for 24h, diseased tissues were examined under a light microscope. Fungal spores were identified and transferred into a fresh water agar plate using a loop with small amount of agar on the tip. After 2 days of culturing in water agar plate, mycelia of the fungus were transferred to fresh water agar for mycelia purification, amplification and were then transferred to filter paper on an oatmeal plate to produce mycelia and spores for long term storage at – 20°C. The fungal spores were produced on the filter paper and used to inoculate susceptible rice plants. Typical blast disease symptoms were observed 7 days after inoculation. This method can aid efforts to study M. oryzae for biological education and for the development of methods to control disease in numerous agronomically important crops.