Submitted to: Inoculum
Publication Type: Abstract Only
Publication Acceptance Date: April 15, 2009
Publication Date: June 8, 2009
Citation: Dixon, L.J., Castlebury, L.A., Glynn, N.C., Comstock, J.C. 2009. Systematics of rust and associated fungi from sugarcane. Inoculum. 60(3):15
The systematic positions of rust pathogens infecting sugarcane (a complex hybrid of Saccharum spp.) were determined using independent and combined sequence data. Rust specimens on sugarcane were sent from 175 locations in 25 countries. In all collections except one, the morphology and nuclear large subunit (nLSU) sequence data matched that of Puccinia kuehnii or P. melanocephala, the orange and brown rust pathogens of sugarcane, respectively. However, nLSU sequences from one collection were distinct from all reported rust sequences available in Genbank from sugarcane and other hosts. The spore morphology of this collection is also distinct from any rust species previously reported on sugarcane and this collection potentially represents an undescribed sugarcane pathogen. Phylogenetic analyses of nuclear ribosomal DNA (rDNA) and beta-tubulin partial gene sequences place this rust species outside the Pucciniaceae. In addition, two different rust-associated mycoparasites were observed in these collections and identified as Sphaerellopsis filum and Hendersonia uredinophila based on their morphology and rDNA sequences. A phylogenetic placement of S. filum and H. uredinophila in the Pleosporales is presented. These fungi should be evaluated for their use as biological control agents in conjunction with fungicides for management of sugarcane rust diseases.