Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2010
Publication Date: 6/1/2010
Citation: Frederick, R.D., Stone, C.L. 2010. Gene expression during appressorium formation by Phakopsora pachyrhizi. Phytopathology. 100:S37.
Technical Abstract: Phakopsora pachyrhizi, which causes Asian soybean rust (ASR), has spread from southern Asia and Australia to Africa and South America, and more recently to North America. At present, U.S. commercial soybean cultivars do not have any resistance to ASR. To develop novel methods for controlling this disease, it is important to understand the molecular processes that occur throughout the infection cycle. This study examined gene expression during appressorium formation, which is required for the pathogen to breach the leaf surface. An appressorium-enriched cDNA library was constructed with mRNA extracted from appressoria produced by germinating urediniospores on polystyrene plates, and subtracting with mRNA extracted from urediniospores germinated on water. A total of 1152 cDNA clones were sequenced and compared to P. pachyrhizi germinating urediniospore ESTs and 31 clones were found only in the appressorium-enriched cDNA library. BlastX analysis revealed sequence similarity to known proteins for 20 clones, and identified three clones as hypothetical proteins. Eight clones showed no significant similarity to protein sequences in GenBank. Genes identified in this study fell into functional categories of metabolism, cell cycle and DNA processing, protein fate, cellular transport, cellular communication and signal transduction, and cell rescue.