Cross-species Global Proteomics Reveals Conserved and Unique Processes in Phytophthora sojae and Phytophthora ramorum

Abstract

Phytophthora ramorum and Phytophthora sojae are destructive plant pathogens. P. sojae has a narrow host range, whereas P. ramorum has a wide host range. A global proteomics comparison of the vegetative (mycelium) and infective (germinating cyst) life stages of P. sojae and P. ramorum was conducted to identify candidate proteins involved in host range, early infection, and vegetative growth. Sixty-two candidates for early infection, 26 candidates for vegetative growth, and numerous proteins that may be involved in defining host specificity were identified. In addition, common life stage proteomic trends between the organisms were observed. In mycelia, proteins involved in transport and metabolism of amino acids, carbohydrates, and other small molecules were up-regulated. In the germinating cysts, up-regulated proteins associated with lipid transport and metabolism, cytoskeleton, and protein synthesis were observed. It appears that the germinating cyst catabolizes lipid reserves through the ␤-oxidation pathway to drive the extensive protein synthesis necessary to produce the germ tube and initiate infection. Once inside the host, the pathogen switches to vegetative growth in which energy is derived from glycolysis and utilized for synthesis of amino acids and other molecules that assist survival in the plant tissue. Molecular & Cellular Proteomics 7:1501-1516, 2008.

Identification of appressorial and mycelial cell wall proteins and a survey of the membrane proteome of Phytophthora infestans

“…CBEL from P. parasitica is cellulose-binding, has lectin-like activity, and is involved in cell wall deposition and adhesion to cellulose in P. parasitica (Gaulin et al 2002). A P. sojae CBEL protein was also recently found to be upregulated in mycelial samples during a proteomics comparison of P. sojae and P. ramorum (Savidor et al 2008). Transglutaminases covalently link free amino acids and peptide bound glutamine to form extensively cross-linked insoluble protein polymers, which may confer structural stability or help form barriers within the cell wall.…”

“…However, given that Meijer et al (2006) reported problems with scaffold and assembly problems due to the repeat sequences present in the P. ramorum cell wall annexin homologue, and given that these genes are in a transposon rich region within the P. infestans genome, it is possible that this gene cluster is not annotated correctly. Savidor et al (2008) also recently reported the upregulation of annexin proteins in the mycelial proteomes of both P. sojae and P. ramorum. The annexin from the oomycete Saprolegnia monoica, homologous to those identified in the present study (Table 3, Fig S6) activates (1-3)-b-D-glucan synthase and co-purifies with (1-3)-b-D-glucan synthase activity (Bouzenzana et al 2006).…”

“…Proteomics studies of oomycetes have previously taken both global approaches, comparing the proteomes of Phytophthora sojae and P. ramorum (Savidor et al 2008) and more specific approaches, for example, looking at the differential regulation of proteins from P. infestans cysts and appressoria (Ebstrup et al 2005) or at the cell wall proteome of P. ramorum (Meijer et al 2006). Here, using liquid chromatography tandem mass spectrometry (LC-MS/MS), and the recently published P. infestans genome sequence (Haas et al 2009), we have carried out a detailed study of the cell wall and membrane proteome of P. infestans to identify proteins that may be important for pathogenicity, or the establishment of disease.…”

Profiling the Secretome and Extracellular Proteome of the Potato Late Blight Pathogen Phytophthora infestans

“…Thirteen proteins with a life stage specific expression pattern were identified by 2D-gel electrophoresis, including CRN2 (31). For P. sojae and P. ramorum, a global proteomic approach was used to detect proteomic differences between life stages (32,33), and a recent large-scale phosphoproteome analysis revealed the phosphorylation status of thousands of proteins and provided novel information on life stage specific phosphorylation events in P. infestans (34). Despite their importance, proteomic studies on Phytophthora extracellular proteins are even more limited.…”

Proteomic Analysis of Phytophthora infestans Reveals the Importance of Cell Wall Proteins in Pathogenicity

“…include the study of Savidor et al who used a label-free approach to compare mycelium and germinating cysts in P. sojae and P. ramorum and could identify several candidate proteins distinguishing the preinfection stage from the mycelial stage (51). In addition, Meijer et al performed an analysis of proteins from isolated P. ramorum cell walls.…”