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In silico analysis of the core signaling proteome from the barley powdery mildew pathogen (Blumeria graminis f.sp. hordei).

Kusch S, Ahmadinejad N, Panstruga R, Kuhn H - BMC Genomics (2014)

Bottom Line: This genomic assemblage is thought to be the result of numerous gene losses, which likely represent an evolutionary adaptation to a parasitic lifestyle in close association with its host plant, barley (Hordeum vulgare).A family of kinases that preferentially occur in pathogenic species of the fungal clade Leotiomyceta is unusually expanded in Bgh and its close relative, Blumeria graminis f.sp. tritici.Our analysis reveals characteristic features of the proteome of a fungal phytopathogen that occupies an extreme habitat: the living plant cell.

View Article: PubMed Central - PubMed

Affiliation: Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, 52056 Aachen, Germany. panstruga@bio1.rwth-aachen.de.

ABSTRACT

Background: Compared to other ascomycetes, the barley powdery mildew pathogen Blumeria graminis f.sp. hordei (Bgh) has a large genome (ca. 120 Mbp) that harbors a relatively small number of protein-coding genes (ca. 6500). This genomic assemblage is thought to be the result of numerous gene losses, which likely represent an evolutionary adaptation to a parasitic lifestyle in close association with its host plant, barley (Hordeum vulgare). Approximately 8% of the Bgh genes are predicted to encode virulence effectors that are secreted into host tissue and/or cells to promote pathogenesis; the remaining proteome is largely uncharacterized at present.

Results: We provide a comparative analysis of the conceptual Bgh proteome, with an emphasis on proteins with known roles in fungal development and pathogenicity, for example heterotrimeric G proteins and G protein coupled receptors; components of calcium and cAMP signaling; small monomeric GTPases; mitogen-activated protein cascades and transcription factors. The predicted Bgh proteome lacks a number of proteins that are otherwise conserved in filamentous fungi, including two proteins that are required for the formation of anastomoses (somatic hyphal connections). By contrast, apart from minor modifications, all major canonical signaling pathways are retained in Bgh. A family of kinases that preferentially occur in pathogenic species of the fungal clade Leotiomyceta is unusually expanded in Bgh and its close relative, Blumeria graminis f.sp. tritici.

Conclusions: Our analysis reveals characteristic features of the proteome of a fungal phytopathogen that occupies an extreme habitat: the living plant cell.

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Related in: MedlinePlus

Predicted MAPK signaling cascades inBgh. The scheme illustrates tentative MAPK signaling modules on the basis of known yeast MAPK cascades [37]. For further details, see Additional file 7: Table S5 (sheet “MAP kinases”).
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Fig4: Predicted MAPK signaling cascades inBgh. The scheme illustrates tentative MAPK signaling modules on the basis of known yeast MAPK cascades [37]. For further details, see Additional file 7: Table S5 (sheet “MAP kinases”).

Mentions: Mitogen activated kinases (MAPKs) are highly conserved eukaryotic protein kinases. They typically function in modules of three-tiered signaling cascades, in which MAPKs are phosphorylated and activated by MAPK-kinases (MAPKKs), which in turn are phosphorylated and activated by MAPKK-kinases (MAPKKKs). MAPKKKs are connected to cell surface sensors via small monomeric GTPases and/or other upstream protein kinases. MAPK signaling is required for appressorium formation in several phytopathogenic and entomopathogenic fungi [31–35]. Analysis of the Bgh proteome revealed the presence of four canonical MAPKKKs (CCU75550, CCU77369, CCU78411 and CCU82598,), three prototypical MAPKKs (CCU75305, CCU76709 and CCU81577) and three archetypal MAPKs (CCU74295, CCU75807 and CCU82891; Additional file 7: Table S5, sheet “MAP kinases”). These proteins harbor characteristic kinase domains (for example PTHR24355, PTHR24360, PTHR24361 or IPR003527), and comprise presumptive orthologs of key MAP(K/K)Ks that are known to have important roles in fungal signaling and development (Figure 4; [36]). In addition to these classical MAP(K/K)Ks, the presence of distinctive protein domains suggests five additional MAPKKKs and three further MAPKs in Bgh. However, some of these proteins appear to be kinases acting upstream of MAPK modules (for example CCU77522 and CCU83089, corresponding to yeast Cla4 and Ste20, respectively) or kinases that have sequence similarity to MAPKKKs/MAPKs, but may not necessarily exert this function.Figure 4


In silico analysis of the core signaling proteome from the barley powdery mildew pathogen (Blumeria graminis f.sp. hordei).

Kusch S, Ahmadinejad N, Panstruga R, Kuhn H - BMC Genomics (2014)

Predicted MAPK signaling cascades inBgh. The scheme illustrates tentative MAPK signaling modules on the basis of known yeast MAPK cascades [37]. For further details, see Additional file 7: Table S5 (sheet “MAP kinases”).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4195978&req=5

Fig4: Predicted MAPK signaling cascades inBgh. The scheme illustrates tentative MAPK signaling modules on the basis of known yeast MAPK cascades [37]. For further details, see Additional file 7: Table S5 (sheet “MAP kinases”).
Mentions: Mitogen activated kinases (MAPKs) are highly conserved eukaryotic protein kinases. They typically function in modules of three-tiered signaling cascades, in which MAPKs are phosphorylated and activated by MAPK-kinases (MAPKKs), which in turn are phosphorylated and activated by MAPKK-kinases (MAPKKKs). MAPKKKs are connected to cell surface sensors via small monomeric GTPases and/or other upstream protein kinases. MAPK signaling is required for appressorium formation in several phytopathogenic and entomopathogenic fungi [31–35]. Analysis of the Bgh proteome revealed the presence of four canonical MAPKKKs (CCU75550, CCU77369, CCU78411 and CCU82598,), three prototypical MAPKKs (CCU75305, CCU76709 and CCU81577) and three archetypal MAPKs (CCU74295, CCU75807 and CCU82891; Additional file 7: Table S5, sheet “MAP kinases”). These proteins harbor characteristic kinase domains (for example PTHR24355, PTHR24360, PTHR24361 or IPR003527), and comprise presumptive orthologs of key MAP(K/K)Ks that are known to have important roles in fungal signaling and development (Figure 4; [36]). In addition to these classical MAP(K/K)Ks, the presence of distinctive protein domains suggests five additional MAPKKKs and three further MAPKs in Bgh. However, some of these proteins appear to be kinases acting upstream of MAPK modules (for example CCU77522 and CCU83089, corresponding to yeast Cla4 and Ste20, respectively) or kinases that have sequence similarity to MAPKKKs/MAPKs, but may not necessarily exert this function.Figure 4

Bottom Line: This genomic assemblage is thought to be the result of numerous gene losses, which likely represent an evolutionary adaptation to a parasitic lifestyle in close association with its host plant, barley (Hordeum vulgare).A family of kinases that preferentially occur in pathogenic species of the fungal clade Leotiomyceta is unusually expanded in Bgh and its close relative, Blumeria graminis f.sp. tritici.Our analysis reveals characteristic features of the proteome of a fungal phytopathogen that occupies an extreme habitat: the living plant cell.

View Article: PubMed Central - PubMed

Affiliation: Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, 52056 Aachen, Germany. panstruga@bio1.rwth-aachen.de.

ABSTRACT

Background: Compared to other ascomycetes, the barley powdery mildew pathogen Blumeria graminis f.sp. hordei (Bgh) has a large genome (ca. 120 Mbp) that harbors a relatively small number of protein-coding genes (ca. 6500). This genomic assemblage is thought to be the result of numerous gene losses, which likely represent an evolutionary adaptation to a parasitic lifestyle in close association with its host plant, barley (Hordeum vulgare). Approximately 8% of the Bgh genes are predicted to encode virulence effectors that are secreted into host tissue and/or cells to promote pathogenesis; the remaining proteome is largely uncharacterized at present.

Results: We provide a comparative analysis of the conceptual Bgh proteome, with an emphasis on proteins with known roles in fungal development and pathogenicity, for example heterotrimeric G proteins and G protein coupled receptors; components of calcium and cAMP signaling; small monomeric GTPases; mitogen-activated protein cascades and transcription factors. The predicted Bgh proteome lacks a number of proteins that are otherwise conserved in filamentous fungi, including two proteins that are required for the formation of anastomoses (somatic hyphal connections). By contrast, apart from minor modifications, all major canonical signaling pathways are retained in Bgh. A family of kinases that preferentially occur in pathogenic species of the fungal clade Leotiomyceta is unusually expanded in Bgh and its close relative, Blumeria graminis f.sp. tritici.

Conclusions: Our analysis reveals characteristic features of the proteome of a fungal phytopathogen that occupies an extreme habitat: the living plant cell.

Show MeSH
Related in: MedlinePlus