Project description:Phytophthora root and stem rot (PRR) caused by oomycete pathogens in the Phytophthora genus poses a significant threat to soybean productivity. While resistance mechanisms against Phytophthora sojae have been extensively studied, the molecular basis underlying immune responses to the newly recognized pathogen, Phytophthora sansomeana, remains largely unknown. In this study, we investigated transcriptomic and epigenetic responses of two resistant (Colfax and NE2701) and two susceptible (Williams 82 and Senaki) soybean lines at four time points (2, 4, 8, and 16 hours post inoculation, hpi) after P. sansomeana inoculation. Through comparative transcriptomic analyses, we identified a greater number of differentially expressed genes (DEGs) upon pathogen inoculation in the resistant lines compared to the susceptible lines, predominantly at 8 and 16 hpi. These DEGs were associated with multiple phytohormones, including ethylene, salicylic acid, and jasmonic acid, along with various transcription factors and signaling cascade proteins. Moreover, DE transposable elements (TEs) were predominantly up-regulated after inoculation, and we found that TEs differentially transcribed in a resistant line were enriched near genes. Notably, we identified a long non-coding RNA (lncRNA) that was significantly differentially transcribed after inoculation exclusively in the resistant lines, potentially regulating two flanking LURP-one-related genes, known as key defense mediators in Arabidopsis against oomycete pathogens. Furthermore, DNA methylation analysis revealed increased CHH (H = A, T, or C) methylation levels in lncRNAs after inoculation, with delayed responses in the resistant line compared to the susceptible line. Overall, our results provide insights into the molecular mechanisms underlying resistance to P. sansomeana in soybean and underscore the potential role of lncRNAs and epigenetic regulation in plant defense responses.
Project description:Phytophthora root and stem rot (PRR) caused by oomycete pathogens in the Phytophthora genus poses a significant threat to soybean productivity. While resistance mechanisms against Phytophthora sojae have been extensively studied, the molecular basis underlying immune responses to the newly recognized pathogen, Phytophthora sansomeana, remains largely unknown. In this study, we investigated transcriptomic and epigenetic responses of two resistant (Colfax and NE2701) and two susceptible (Williams 82 and Senaki) soybean lines at four time points (2, 4, 8, and 16 hours post inoculation, hpi) after P. sansomeana inoculation. Through comparative transcriptomic analyses, we identified a greater number of differentially expressed genes (DEGs) upon pathogen inoculation in the resistant lines compared to the susceptible lines, predominantly at 8 and 16 hpi. These DEGs were associated with multiple phytohormones, including ethylene, salicylic acid, and jasmonic acid, along with various transcription factors and signaling cascade proteins. Moreover, DE transposable elements (TEs) were predominantly up-regulated after inoculation, and we found that TEs differentially transcribed in a resistant line were enriched near genes. Notably, we identified a long non-coding RNA (lncRNA) that was significantly differentially transcribed after inoculation exclusively in the resistant lines, potentially regulating two flanking LURP-one-related genes, known as key defense mediators in Arabidopsis against oomycete pathogens. Furthermore, DNA methylation analysis revealed increased CHH (H = A, T, or C) methylation levels in lncRNAs after inoculation, with delayed responses in the resistant line compared to the susceptible line. Overall, our results provide insights into the molecular mechanisms underlying resistance to P. sansomeana in soybean and underscore the potential role of lncRNAs and epigenetic regulation in plant defense responses.
2023-11-24 | GSE240964 | GEO
Project description:First Draft Genome Resource of Phytophthora sansomeana Strain Psa-2310
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.