Project description:Crop breeding aims to balance disease resistance with yield; however, single resistance (R) genes can lead to resistance breakdown, and R gene pyramiding may affect growth fitness. Here we report that the rice Pigm locus contains a cluster of genes encoding nucleotide-binding leucine-rich repeat (NLR) receptors that confer durable resistance to the fungus Magnaporthe oryzae without yield penalty. Among these NLR receptors, PigmR confers broad-spectrum resistance, whereas PigmS competitively attenuates PigmR homodimerization to suppress resistance. PigmS expression, and thus PigmR-mediated resistance, are subjected to tight epigenetic regulation. PigmS increases seed production to counteract the yield cost induced by PigmR Therefore, our study reveals a mechanism balancing high disease resistance and yield through epigenetic regulation of paired antagonistic NLR receptors, providing a tool to develop elite crop varieties.
Project description:Nucleotide-binding site leucine-rich repeat (NLR) receptors perceive pathogen effectors and trigger plant immunity. However, the mechanisms underlying NLR-triggered defense responses remain obscure. The recently discovered Pigm locus in rice encodes a cluster of NLRs, including PigmR, which confers broad-spectrum resistance to blast fungus. Here, we identify PIBP1 (PigmR-INTERACTING and BLAST RESISTANCE PROTEIN 1), an RRM (RNA-recognition motif) protein that specifically interacts with PigmR and other similar NLRs to trigger blast resistance. PigmR-promoted nuclear accumulation of PIBP1 ensures full blast resistance. We find that PIBP1 and a homolog, Os06 g02240, bind DNA and function as unconventional transcription factors at the promoters of the defense genes OsWAK14 and OsPAL1, activating their expression. Knockout of PIBP1 and Os06g02240 greatly attenuated blast resistance. Collectively, our study discovers previously unappreciated RRM transcription factors that directly interact with NLRs to activate plant defense, establishing a direct link between transcriptional activation of immune responses with NLR-mediated pathogen perception
Project description:Nucleotide-binding site leucine-rich repeat (NLR) receptors perceive pathogen effectors and trigger plant immunity. However, the mechanisms underlying NLR-triggered defense responses remain obscure. The recently discovered Pigm locus in rice encodes a cluster of NLRs, including PigmR, which confers broad-spectrum resistance to blast fungus. Here, we identify PIBP1 (PigmR-INTERACTING and BLAST RESISTANCE PROTEIN 1), an RRM (RNA-recognition motif) protein that specifically interacts with PigmR and other similar NLRs to trigger blast resistance. PigmR-promoted nuclear accumulation of PIBP1 ensures full blast resistance. We find that PIBP1 and a homolog, Os06 g02240, bind DNA and function as unconventional transcription factors at the promoters of the defense genes OsWAK14 and OsPAL1, activating their expression. Knockout of PIBP1 and Os06 g02240 greatly attenuated blast resistance. Collectively, our study discovers previously unappreciated RRM transcription factors that directly interact with NLRs to activate plant defense, establishing a direct link between transcriptional activation of immune responses with NLR-mediated pathogen perception.
Project description:Nucleotide-binding site leucine-rich repeat (NLR) receptors perceive pathogen effectors and trigger plant immunity. However, the mechanisms underlying NLR-triggered defense responses remain obscure. The recently discovered Pigm locus in rice encodes a cluster of NLRs, including PigmR, which confers broad-spectrum resistance to blast fungus. Here, we identify PIBP1 (PigmR-INTERACTING and BLAST RESISTANCE PROTEIN 1), an RRM (RNA-recognition motif) protein that specifically interacts with PigmR and other similar NLRs to trigger blast resistance. PigmR-promoted nuclear accumulation of PIBP1 ensures full blast resistance. We find that PIBP1 and a homolog, Os06 g02240, bind DNA and function as unconventional transcription factors at the promoters of the defense genes OsWAK14 and OsPAL1, activating their expression. Knockout of PIBP1 and Os06g02240 greatly attenuated blast resistance. Collectively, our study discovers previously unappreciated RRM transcription factors that directly interact with NLRs to activate plant defense, establishing a direct link between transcriptional activation of immune responses with NLR-mediated pathogen perception
Project description:MicroRNAs (miRNAs) are small non-coding RNAs that function as post-transcriptional regulators of gene expression in eukaryotes. In rice, miR7695 targets an alternatively spliced transcript of natural resistance-associated macrophage protein 6 (OsNramp6) encoding an iron transporter whose expression is regulated by infection with the rice blast fungus Magnaporthe oryzae. Rice plants grown under high iron supply showed blast resistance, which supports that iron is a factor in controlling blast resistance by still unknown mechanisms. Here, iron accumulated near M. oryzae appressoria, the sites of pathogen entry, and in cells surrounding infected regions of the rice leaf. Activation-tagged MIR7695 rice plants (MIR7695-Ac) exhibited enhanced resistance to M. oryzae infection. RNA-seq analysis revealed that blast resistance in MIR7695-Ac plants was associated with strong induction of defense-related genes, including pathogenesis-related and diterpenoid biosynthetic genes. Levels of phytoalexins during pathogen infection were higher in MIR7695-Ac than wild-type plants. Early phytoalexin biosynthetic genes, OsCPS2 and OsCSP4, were highly upregulated in rice plants grown under high iron supply. Our data indicate that miR7695 positively regulates rice immunity while establishing links between defense and iron signaling in rice. MiR7695-mediated regulation of OsNramp6 has great potential for the development of strategies to control rice blast disease.
Project description:Rice (Oryza sativa) is one of the world's major rations. The widely planted hybrid rice in Jiangxi Province is seriously affected by Magnaporthe oryzae, which seriously restricts the rice yield in Jiangxi Province. In recent years, studies have found that alternative polyadenylation (APA) is an important post-transcriptional regulation in eukaryotes. The genetic law and function of APA in the occurrence of hybrid rice blast in Jiangxi are not clear. In this study, Wufengyou T025 (WFY) and its parents (male parent Changhui T025(CH), and female parent Wufeng B(WFB)) were used as the research objects. Transcriptome and metabolome sequencing, combined with a variety of bioinformatics analysis methods and modern molecular biology experimental techniques, revealed the APA expression profile during the occurrence of Jiangxi hybrid rice blast. To explore the regulatory mechanism of APA core factors during the occurrence of rice blast. This study not only provides a new understanding of the occurrence of Jiangxi hybrid rice blast, but also provides more abundant resources for molecular breeding.
Project description:NPR1 is a central positive regulator of salicylic-acid (SA)-mediated defense signaling in Arabidopsis. Here, we report characterization of OsNPR1, an Oryzae sativa (rice) ortholog of NPR1, focusing on its role in blast disease resistance and identification of OsNPR1-regulated genes followed by their comparison with NPR1-regulated genes in Arabidopsis. Blast resistance tests using OsNPR1–knockdown and –overexpressing rice lines indicated that OsNPR1 plays an essential role in benzothiadiazole-induced blast resistance. Genome-wide transcript profiling using OsNPR1–knockdown lines revealed that 358 genes out of 1,228 BTH-upregulated genes and 724 genes out of 1,069 BTH-downregulated genes were OsNPR1 dependent with respect to their BTH responsiveness, indicating that OsNPR1 plays a major role in the downregulation. Inspection of OsNPR1-dependent genes revealed that many genes involved in photosynthesis and chloroplastic translation and transcription were downregulated by BTH in an OsNPR1 dependent manner, indicating that photosynthesis and chloroplast activities is coordinately suppressed by OsNPR1 in response to BTH-induced activation of SA-signaling pathway. ABA-responsive genes were also OsNPR1-dependently downregulated, suggesting antagonistic interaction of SA signaling on ABA signaling. None of 11 BTH-upregulated genes for WRKY transcription factors was OsNPR1 dependent, whereas most of those are NPR1-dependently upregulated in Arabidopsis, indicating that the role of OsNPR1 is distinct from that of NPR1 in Arabidopsis. We discuss the significance of OsNPR1-regulated gene expression in SA-regulated defense program and the role of OsNPR1 in rice SA-signaling pathway that is branched to OsNPR1- and rice WRKY45-dependent sub-pathways. mock-treated wild-type (Nipponbare) rice, benzothiadiazole (BTH)-treated wild-type rice, mock-treated WRKY45-knockdown rice (2 lines) and BTH-treated WRKY45-knockdown rice (2 lines) were analyzed in four biological replicates.
Project description:Rice is a staple food crop worldwide, and its production is severely threatened by phloem-feeding insect herbivores, particularly the brown planthopper (BPH, Nilaparvata lugens), and destructive pathogens. Despite the identification of many BPH resistance genes, the molecular basis of rice resistance to BPH remains largely unclear. Here, we report that the plant elicitor peptide (Pep) signalling confers rice resistance to BPH. Both rice PEP RECEPTORs (PEPRs) and PRECURSORs of PEP (PROPEPs), particularly OsPROPEP3, were transcriptionally induced in leaf sheaths upon BPH infestation. Knockout of OsPEPRs impaired rice resistance to BPH, whereas exogenous application of OsPep3 improved the resistance. Hormone measurement and co-profiling of transcriptomics and metabolomics in OsPep3-treated rice leaf sheaths suggested potential contributions of jasmonic acid biosynthesis, lipid metabolism and phenylpropanoid metabolism to OsPep3-induced rice immunity. Moreover, OsPep3 elicitation also strengthened rice resistance to the fungal pathogen Magnaporthe oryzae and bacterial pathogen Xanthamonas oryzae pv. oryzae and provoked immune responses in wheat. Collectively, this work demonstrates a previously unappreciated importance of the Pep signalling in plants for combating piercing-sucking insect herbivores and promises exogenous application of OsPep3 as an eco-friendly immune stimulator in agriculture for crop protection against a broad spectrum of insect pests and pathogens.
Project description:Rice roots grown in hydroponic culture were inoculated with rice blast fungus and gene expression profiles were analyzed by microarray Roots of two isogenic lines of rice cv Nipponbare (blast-resistance gene: Pia or pia) were inoculated with rice blast fungus, P91-15B, carrying avirulence gene, AvrPia. Total RNA was isolated from crown roots, labeled with cy3, and probed with agilent rice oligoarray (4x44).
Project description:Fourth leaves of rice seedlings (4.5 leaf stage) grown in hydroponic culture were inoculated with rice blast fungus and gene expression profiles were analyzed by microarray. Fourth leaves of the two isogenic lines of rice cv Nipponbare (blast-resistance gene: Pia or its mutant, pia) were inoculated with rice blast fungus, P91-15B, carrying avirulence gene, AvrPia. Total RNA was isolated, labeled with cy3, and probed with agilent rice oligoarray (4x44).