Project description:Seedlings grown from seeds from open-pollinated mother trees of genotype UF12 were grown and at two months of age used to analyze response to treatment with the fungal pathogen Colletotrichum theobromicola and the oomycete pathogen Phytophthora palmivora.
Project description:Here, we define the proteomic response of the early divergent liverwort Marchantia polymorpha during infection with the oomycete pathogen Phytophthora palmivora. We sampled whole liverwort thalli that were mock-inoculated (water) or infected with P. palmivora zoospores at 4 and 8 days post inoculation (dpi). This analysis revealed the protein profiles of liverworts during the biotrophic (4 dpi) and necrotrophic (8 dpi) stages of pathogen infection. In combination with additional omics datasets, our analyses reveal conserved aspects in the molecular response to pathogen infection in liverworts and angiosperms.
Project description:The oomycete Phytophthora palmivora infects a wide range of tropical crops worldwide. Like other filamentous plant pathogens, it secretes effectors to colonise plant tissues. Here we characterise FIRE, an RXLR effector that contains a canonical mode I 14-3-3 phospho-sensor binding motif that is conserved in effectors of several Phytophthora species. FIRE is phosphorylated in planta and interacts with multiple 14-3-3 proteins. Binding is sensitive to the R18 14-3-3 inhibitor. FIRE promotes plant susceptibility and co-localises with its target around haustoria. This work uncovers a new type of oomycete effector target mechanism. It demonstrates that substrate mimicry for 14-3-3 proteins is a cross-kingdom effector strategy used by both prokaryotic and eukaryotic plant pathogens to suppress host immunity.
Project description:Centromeres are chromosomal regions that serve as platforms for kinetochore assembly and spindle attachments, ensuring accurate chromosome segregation during cell division. Despite functional conservation, centromeric sequences are diverse and usually repetitive across species, making them challenging to assemble and identify. Here, we describe centromeres in the model oomycete Phytophthora sojae by combining long-read sequencing-based genome assembly and chromatin immunoprecipitation for the centromeric histone CENP-A followed by high-throughput sequencing (ChIP-seq). P. sojae centromeres cluster at a single focus in the nucleus at different life stages and during nuclear division. We report a highly contiguous genome assembly of the P. sojae reference strain, which enabled identification of 15 highly enriched CENP-A binding regions as putative centromeres. By focusing on 10 intact regions, we demonstrate that centromeres in P. sojae are regional, spanning 211 to 356 kb. Most of these regions are transposon-rich, poorly transcribed, and lack the euchromatin mark H3K4me2 but are embedded within regions with the heterochromatin marks H3K9me3 and H3K27me3.
Project description:Dendrobium necrosis-inducing elicitin (DNIE), a new member of the elicitin family of Phytophthora palmivora and its toxicity in Dendrobium
Project description:Phytophthora is arguably one of the most damaging genera of plant pathogens and is recognized as a threat to a broad spectrum of plant species. This pathogen is well suited to transmission via the international plant trade, and globalization has been promoting its spread since the 19th century. Early detection is essential for its effective control and of paramount importance in reducing the economic and ecological impact. The increasing sensitivity of the mass spectrometry-based detection indicates that a protein-based analysis may soon complement routine molecular techniques for pathogen detection. Here, a shotgun proteomics approach was utilized for Phytophthora analysis. The collection of 37 Phytophthora isolates representing 12 different species was screened, and species-specific peptide patterns were identified. Next, Phytophthora proteins were detected in planta, employing model plants S. tuberosum and H. vulgare. Although the evolutionarily conserved sequences represented more than 10% of the host proteome and limited the pathogen detection, the comparison between qPCR and protein data highlighted more than 300 protein markers correlated positively with the amount of P. infestans DNA. Finally, the analysis of P. palmivora response in barley proteome and metabolome revealed significant alterations in primary metabolism, providing the first insight into molecular mechanisms behind this biotic interaction.