Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2010
Publication Date: June 15, 2010
Citation: Crouch, J., Szabo, L.J. 2010. Real-time PCR detection of the southern corn rust pathogen Puccinia polysora [abstract]. Phytopathology. 100:S27. Technical Abstract: Southern rust, caused by Puccinia polysora, is an increasingly problematic disease of corn (Zea mays) in the U.S. The fungus has been present in North America since at least 1897, with epidemics occurring episodically throughout the 20th century in Africa, China, Central and South America. Although primarily a foliar disease, P. polysora may also infect sheaths and husk leaves, causing severe and early senescence. Stem lodging may also occur as an indirect result of photosynthate loss, and yield reductions may be considerable. Southern rust may be distinguished from common corn rust caused by P. sorghi through expert examination of pustule color, pustule location, and spore morphology, but the differences between the two diseases and the causal organisms may be subtle or even impossible to detect, especially in early stages of disease development. Therefore, to reliably differentiate between these two pathogens, a real-time PCR assay based on the nuclear ribosomal internal transcribed spacer region has been developed for P. polysora and P. sorghi. This assay will be useful for monitoring and evaluating the distribution and incidence of southern corn rust in the U.S.