Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 3/31/2007
Publication Date: 8/1/2007
Citation: Luster, D.G., Mcmahon, M.B. 2007. Extracellular proteins from the Phakopsora pachyrhizi spore wall. Phytopathology. 97:S68
Technical Abstract: Phakopsora pachyrhizi is the causal agent of Asian soybean rust, a disease of leguminous plants that has recently become established in the U.S. We previously applied two-dimensional gel electrophoresis and MALDI-TOF/TOF mass spectrometry to identify a set of extracellular proteins that were washed from urediniospores following 18 hours germination on sterile water. These proteins were mapped to cDNA clones from a P. pachyrhizi EST library, and a subset of five full length open reading frames were overexpressed in E. coli. The resulting recombinant proteins were then used to generate polyclonal antibodies. The antibodies recognized native forms of the proteins in P. pachyrhizi urediniospore extracts and in extracts from plants infected with P. pachyrhizi 3 to 14 days post inoculation. In previous analyses, all five of the secreted proteins contained predicted amino acid motifs for N- or O- linked glycosylation. Lectin blots have verified glycosylation patterns for three of the native P. pachyrhizi proteins. Antibodies are being applied in studies to localize these proteins in the extracellular spore matrix, and in functional assays to identify their roles in the infection processes.