Project description:Burkholderia glumae causes rice grain rot and sheath rot by producing toxoflavin, whose expression is regulated by quorum sensing (QS). The QS systems of the bacterium rely on N-octanoyl homoserine lactone, synthesized by TofI and its cognate receptor TofR, to activate toxoflavin biosynthesis genes and an IclR-type transcriptional regulator gene, qsmR. To understand genome-wide transcriptional profiling of QS signaling, we employed RNA-Seq of the wild type Burkholderia glumae BGR1 and two QS-defective mutants, BGS2 (BGR1 tofI::Ω) and BGS9 (BGR1 qsmR::Ω), with two different types of culture conditions including 6hr liquid culture (before onset QS) and 10hr liquid culture (after onset QS).
Project description:Burkholderia glumae causes rice grain rot and sheath rot by producing toxoflavin, whose expression is regulated by quorum sensing (QS). The QS systems of the bacterium rely on N-octanoyl homoserine lactone, synthesized by TofI and its cognate receptor TofR, to activate toxoflavin biosynthesis genes and an IclR-type transcriptional regulator gene, qsmR. To understand genome-wide transcriptional profiling of QS signaling, we employed RNA-Seq of the wild type Burkholderia glumae BGR1 and two QS-defective mutants, BGS2 (BGR1 tofI::Ω) and BGS9 (BGR1 qsmR::Ω), with two different types of culture conditions including 6hr liquid culture (before onset QS) and 10hr liquid culture (after onset QS). 3 samples examined: Burkholderia glumae BGR1 wild type, and two QS-defective mutants, BGS2 (BGR1 tofI::Ω) and BGS9 (BGR1 qsmR::Ω). Two conditions: cultured in LB media for 6hrs or 10hrs.
Project description:Pls4 is a gene encoding a β -ketoacyl carrier protein reductase (KAR), which is mainly involved in biological processes such as cell membrane formation. However,the role of pls4 in rice sheath blight remains unclear. Our preliminary studies showed that rice pls4 mutants were highly susceptive to sheath blight in early development stage, and insensitive in adulthood. To explore the role of this gene in the occurrence of rice sheath blight, we compared the transcriptome profiles of rice pls4 mutant and wild-type by RNA-seq. The results showed that, 2569 differentially expressed genes (DEGs), and down-regulated genes were significantly enriched in defense response related biological stress. The expression pattern significantly changed in genes related to pattern-triggered immunity (PTI) and effector-triggered immunity (ETI), which were the main two innate immunity pathways in plants. The chitinase-related genes were mainly down-regulated, while both the disease-related genes and the related genes of the WRKY gene family were significantly up-regulated. Furthermore, 467 genes had significantly alternative splicing (AS) events. Among them, intron retention (IR) affected the gene expression levels and functions in vitamin B6 (VB6) metabolism pathway, which was related to sheath blight. This suggested that IR played an important role in sheath blight resistance of mutant pls4. In conclusion, these studies suggested that pls4 might be involved in the biological stress process of sheath blight by DEGs and the fine-tuning of IR, which would provide a molecular basis for the study of rice sheath blight resistance.
Project description:Rice (Oryza sativa L.) is one of the most important staple foods in the world, feeding more than 50% of the human population. One of its most damaging pathogens, with major impact on rice yield, is the migratory root rot nematode Hirschmanniella oryzae. In comparison with the existing knowledge on the infection process of dicots by sedentary nematodes, far less is known about the interaction between monocot plants and nematodes or plant interactions with migratory nematode species. Therefore, to gain deeper insight into the systemic transcriptional changes in rice after migratory root rot nematode infection we have performed mRNA-Seq on the shoots of root rot nematode infected rice plants. The observations were independently validated using qRT-PCR and biochemical analyses. This research reveals significant modifications in the metabolism of the plant, with a general suppression of chlorophyll biosynthesis, and primary metabolic processes involved in plant growth . Differential expression analysis between controls rice shoots and shoots from root rot nematode (H. oryzae) infected rice at two time points.
Project description:We carried out an RNA-seq based transcriptome study on two rice varieties, Cocodrie (CCDR; rice sheath blight susceptible) and MCR10277 (MCR; rice sheath blight resistant), to profile the time-series wide genome-scale transcriptional differences in response to sheath blight (SB), an infection caused by R. solanii (LR172) . Our approach is cross-referencing differentially expressed genes with significant variants of two phenotypically different varieties to validate known and discover novel variants and to further understand rice's physiological response to SB.
Project description:The hemibiotrophic fungus Magnaporthe oryzae produces specialized biotrophic invasive hyphae (IH) that alter membrane structure and defense responses in invaded rice cells. IH successively invade live neighbor cells, apparently through plasmodesmata. Understanding fungal and rice genes that contribute to biotrophic invasion has been a challenge because so few plant cells have encountered IH at the earliest infection stages. Using a rice sheath inoculation method, we successfully enriched for infected tissue RNA that contained ~20% fungal RNA at a point when most IH were still growing in first-invaded rice cells. The RNAs were analyzed using the whole-genome M. oryzae oligoarray and a rice oligoarray. Rice genes that were induced >50-fold during infection were enriched for genes involved in transferring information from sensors to cellular responses. Fungal genes that were induced >50-fold in IH included the PWL2 avirulence gene and genes encoding hypothetical secreted proteins. The IH-specific secreted proteins are candidate effectors, proteins that the fungus secretes into live host cells to control cellular processes. Gene knock-out analyses of three putative effector genes failed to show major effects on pathogenicity. Details of the blast interaction transcriptome will provide insights on the mechanisms of biotrophic plant disease. Keywords: Disease state analysis Our goal was to compare expression in biotrophic IH to expression in mycelium grown in nutrient medium, and to compare expression in infected rice sheath to expression in mock inoculated rice. Using version 2 of the fungal whole genome microarray (Agilent Technologies), we analyzed samples from three biological replicates of rice leaf sheath at 36 hours after inoculation with the rice blast fungus M. oryzae. The same samples were used with the Agilent rice microarray (see series GSE8518). To estimate the ratio of fungal to rice RNAs in the infected sheaths, we compared RT-PCR amplification of fungal genes in infected tissue to amplification in standards produced by mixing known ratios of pure mycelial RNA with mock-inoculated rice RNA. Using this assay, fungal RNA content in infected tissues were approximately 20% of the total RNAs. We prepared control mixtures by pooling 20% mycelial RNA and 80% RNA from mock-inoculated rice sheath. Complementary RNAs from infected tissues were labeled with Cy3 or Cy5 and hybridized together with the control mixture RNA labeled with the other dye. Three independent biological replications were performed, with separate hybridizations for 2 technical replications and corresponding dye swap experiments. Data were analyzed by Rosetta Resolver® and showed a correlation of over 80% between biological replications.
Project description:Rice (Oryza sativa L.) is one of the most important staple foods in the world, feeding more than 50% of the human population. One of its most damaging pathogens, with major impact on rice yield, is the migratory root rot nematode Hirschmanniella oryzae. In comparison with the existing knowledge on the infection process of dicots by sedentary nematodes, far less is known about the interaction between monocot plants and nematodes or plant interactions with migratory nematode species. Therefore, to gain deeper insight into the systemic transcriptional changes in rice after migratory root rot nematode infection we have performed mRNA-Seq on the shoots of root rot nematode infected rice plants. The observations were independently validated using qRT-PCR and biochemical analyses. This research reveals significant modifications in the metabolism of the plant, with a general suppression of chlorophyll biosynthesis, and primary metabolic processes involved in plant growth .
Project description:The hemibiotrophic fungus Magnaporthe oryzae produces specialized biotrophic invasive hyphae (IH) that alter membrane structure and defense responses in invaded rice cells. IH successively invade live neighbor cells, apparently through plasmodesmata. Understanding fungal and rice genes that contribute to biotrophic invasion has been a challenge because so few plant cells have encountered IH at the earliest infection stages. Using a rice sheath inoculation method, we successfully enriched for infected tissue RNA that contained ~20% fungal RNA at a point when most IH were still growing in first-invaded rice cells. The RNAs were analyzed using the whole-genome M. oryzae oligoarray and a rice oligoarray. Rice genes that were induced >50-fold during infection were enriched for genes involved in transferring information from sensors to cellular responses. Fungal genes that were induced >50-fold in IH included the PWL2 avirulence gene and genes encoding hypothetical secreted proteins. The IH-specific secreted proteins are candidate effectors, proteins that the fungus secretes into live host cells to control cellular processes. Gene knock-out analyses of three putative effector genes failed to show major effects on pathogenicity. Details of the blast interaction transcriptome will provide insights on the mechanisms of biotrophic plant disease. Experiment Overall Design: Our goal was to compare expression in infected rice sheath to expression in mock inoculated rice, and to compare expression in biotrophic IH to expression in mycelium grown in nutrient medium. Using the rice microarray (Agilent Technologies), we analyzed samples from three biological replicates of rice leaf sheath at 36 hours after inoculation with the rice blast fungus M. oryzae. The same samples were used with the Agilent M. oryzae microarray (see series GSE8517). To estimate the ratio of fungal to rice RNAs in the infected sheaths, we compared RT-PCR amplification of fungal genes in infected tissue to amplification in standards produced by mixing known ratios of pure mycelial RNA with mock-inoculated rice RNA. Using this assay, fungal RNA content in infected tissues were approximately 20% of the total RNAs. We prepared control mixtures by pooling 20% mycelial RNA and 80% RNA from mock-inoculated rice sheath. Complementary RNAs from infected tissues were labeled with Cy3 or Cy5 and hybridized together with the control mixture RNA labeled with the other dye. Three independent biological replications were performed, with separate hybridizations for 2 technical replications and corresponding dye swap experiments. Data were analyzed by Rosetta Resolver® and showed a correlation of over 80% between biological replications.