Project description:Pseudomonas syringae pv. phaseolicola (Pph) is a significant bacterial pathogen of agricultural crops, and phage Φ6 and other members of the dsRNA virus family Cystoviridae undergo lytic (virulent) infection of Pph, using the type IV pilus as the initial site of cellular attachment. Despite the popularity of Pph/phage Φ6 as a model system in evolutionary biology, Pph resistance to phage Φ6 remains poorly characterized. To investigate differences between phage Φ6 resistant Pseudomonas syringae pathovar phaseolicola strains, we performed expression analysis of super and non piliated strains of Pseudomonas syringae to determine the genetic cause of resistance to viral infection.
Project description:Purpose: Pseudomonas syringae pv. actinidiae (Psa) is a phytopathogen that causes devastating bacterial canker in kiwifruit. Among five biovars defined by genetic, biochemical and virulence traits, Psa3 is the most aggressive and is responsible for the most recent reported outbreaks, but the molecular basis of its heightened virulence is unclear. A custom P. syringae multi-strain whole-genome microarray platform, encompassing biovars Psa1, Psa2 and Psa3 and the well-established model P. syringae pv. tomato, was used to analyse early bacterial responses to an apoplast-like minimal medium. Conlusion: this work highlighted that diverse early responses to the host apoplast, even among bacteria belonging to the same pathovar, can lead to different virulence strategies and may explain the differing outcomes of infections.
2021-01-09 | GSE164472 | GEO
Project description:Whole genome sequencing of Pseudomonas syringae pathovar lachrymans Pla107
Project description:Pseudomonas syringae is an important plant pathogen that infects a wide variety of crops. The mgo (mangotoxin-generating operon) gene cluster produces an extracellular signaling molecule, leudiazen, and is highly conserved in Pseudomonas syringae strains. Here, we genetically removed mgo in Pseudomonas syringae pv. syringae (Pss) UMAF0158 to interrogate its impacts on bacterial infection. Loss of mgo not only alleviated the chlorosis symptom caused by Pss UMAF0158 infection, but also reduced bacterial population in tomato leaflets. Structure-activity relationship revealed that the diazeniumdiolate group and the isobutyl side chain of leudiazen are critical for its signaling activity. Through global transcriptome analysis, we found that mgo regulates the expression of a new gene cluster in addition to mangotoxin biosynthetic operon, namely RS17235-RS17245. This new gene cluster contributes to in planta survival of Pss UMAF0158 and is widely distributed in Pseudomonas syringae strains. Our results demonstrate that chemical signaling systems in plant pathogens play prominent roles in virulence and population increase and set stages for understanding downstream components of mgo-regulated signaling pathways.
Project description:Leaf-to-leaf, systemic immune signaling known as systemic acquired resistance (SAR) is poorly understood in monocotyledonous plants. Here, we characterize systemic immunity in barley (Hordeum vulgare) triggered after primary leaf infection with either Pseudomonas syringae pathovar japonica (Psj) or Xanthomonas translucens pathovar cerealis (Xtc). Both pathogens induced resistance in systemic, uninfected leaves against a subsequent challenge infection with Xtc. In contrast to SAR in Arabidopsis thaliana, systemic immunity in barley was not associated with NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 or the local or systemic accumulation of salicylic acid (SA). Instead, we documented a moderate local but not systemic induction of abscisic acid (ABA) after infection of leaves with Psj. In contrast to SA or its functional analog benzothiadiazole, local applications of the jasmonic acid methyl ester or ABA triggered systemic immunity to Xtc. RNA-seq analysis of local and systemic transcript accumulation revealed unique gene expression changes in response to both Psj and Xtc and a clear separation of local from systemic responses. The systemic response appeared relatively modest and quantitative RT-PCR associated systemic immunity with the local and systemic induction of two WRKY and two ETHYLENE RESPONSIVE FACTOR-like transcription factors. Systemic immunity against Xtc was further associated with transcriptional changes after a secondary/systemic Xtc challenge infection; these changes were dependent on the primary treatment. Taken together, bacteria-induced systemic immunity in barley may be mediated in part by WRKY and ERF-like transcription factors possibly facilitating transcriptional reprogramming to potentiate immunity.
Project description:Leaf-to-leaf, systemic immune signaling known as systemic acquired resistance (SAR) is poorly understood in monocotyledonous plants. Here, we characterize systemic immunity in barley (Hordeum vulgare) triggered after primary leaf infection with either Pseudomonas syringae pathovar japonica (Psj) or Xanthomonas translucens pathovar cerealis (Xtc). Both pathogens induced resistance in systemic, uninfected leaves against a subsequent challenge infection with Xtc. In contrast to SAR in Arabidopsis thaliana, systemic immunity in barley was not associated with NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 or the local or systemic accumulation of salicylic acid (SA). Instead, we documented a moderate local but not systemic induction of abscisic acid (ABA) after infection of leaves with Psj. In contrast to SA or its functional analog benzothiadiazole, local applications of the jasmonic acid methyl ester or ABA triggered systemic immunity to Xtc. RNA-seq analysis of local and systemic transcript accumulation revealed unique gene expression changes in response to both Psj and Xtc and a clear separation of local from systemic responses. The systemic response appeared relatively modest and quantitative RT-PCR associated systemic immunity with the local and systemic induction of two WRKY and two ETHYLENE RESPONSIVE FACTOR-like transcription factors. Systemic immunity against Xtc was further associated with transcriptional changes after a secondary/systemic Xtc challenge infection; these changes were dependent on the primary treatment. Taken together, bacteria-induced systemic immunity in barley may be mediated in part by WRKY and ERF-like transcription factors possibly facilitating transcriptional reprogramming to potentiate immunity.