106 research outputs found

    The molecular basis of host specialization in bean pathovars of Pseudomonas syringae

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    Biotrophic phytopathogens are typically limited to their adapted host range. In recent decades, investigations have teased apart the general molecular basis of intraspecific variation for innate immunity of plants, typically involving receptor proteins that enable perception of pathogen-associated molecular patterns or avirulence elicitors from the pathogen as triggers for defense induction. However, general consensus concerning evolutionary and molecular factors that alter host range across closely related phytopathogen isolates has been more elusive. Here, through genome comparisons and genetic manipulations, we investigate the underlying mechanisms that structure host range across closely related strains of Pseudomonas syringae isolated from different legume hosts. Although type III secretionindependent virulence factors are conserved across these three strains, we find that the presence of two genes encoding type III effectors (hopC1 and hopM1) and the absence of another (avrB2) potentially contribute to host range differences between pathovars glycinea and phaseolicola. These findings reinforce the idea that a complex genetic basis underlies host range evolution in plant pathogens. This complexity is present even in host–microbe interactions featuring relatively little divergence among both hosts and their adapted pathogens

    Draft genome sequences for Pantoea ananatis ATCC 35400 and Pantoea stewartii subspecies indologenes ICMP 10132

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    DATA AVAILABILITY : This Whole Genome Shotgun project for P. ananatis ATCC 35400 has been deposited in DDBJ/ENA/GenBank under accession no. JARNMU000000000. The version described in this paper is the first version, JARNMU010000000. Raw reads used to generate this assembly can be found at SRX19856715, SRX19856716, and SRX19856717. This Whole Genome Shotgun project for P. stewartii ICMP 10132 has been deposited in DDBJ/ENA/ GenBank under accession no. JARNMT000000000. The version described in this paper is the first version, JARNMT010000000. Raw reads used to generate this assembly can be found at SRX19854976 and SRX19854977.Here, we describe draft genome sequences for two bacterial isolates from the genus Pantoea. Pantoea ananatis ATCC 35400 was originally isolated from honeydew melon and was obtained from the American Type Culture Collection. Pantoea stewartii subspecies indologenes ICMP 10132 was originally isolated from sugarcane and classified as Pantoea ananatis, but average nucleotide identity and discriminatory PCR support species reclassification.The National Science Foundation (NSF).https://journals.asm.org/journal/mrahj2024BiochemistryGeneticsMicrobiology and Plant PathologySDG-15:Life on lan

    Pantailocins : phage-derived bacteriocins from Pantoea ananatis and Pantoea stewartii subsp. indologenes

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    SUPPLEMENTARY MATERIAL : FILE S1. Alignment file for sheath protein sequences to recreate phylogenies in manuscript. FILE S2. Alignment file for J plate protein sequences to recreate phylogenies in manuscript. FIGURE S1. A Model For Invertase Activity in the P. stewartii ICMP 10132 Tailocin Locus.ERRATUM : Volume 89, no. 12, e00471-23, 2023, https://doi.org/10.1128/aem.00929-23. The affiliations and the affiliation numbers for each author should appear as shown in this erratum.Phage-derived bacteriocins are highly specific and effective antimicrobial molecules, which have successfully been used as prophylactic treatments to prevent phytopathogen infections. Given the specificity of tailocins, a necessary step for broadening the tailocin catalog and for extending applicability across systems and diseases is the screening of new clades of phytopathogens for the production of molecules with tailocin-like killing activity. Here, we describe the production by and sensitivity of strains to tailocins produced by Pantoea ananatis and Pantoea stewartii subsp. indologenes. Phylogenetic evidence suggests that these tailocins are derived from Myoviridae family phage like many previously described R-type tailocins but also suggests that cooption from phage occurred independently of previously described tailocins. Since these tailocin encoding loci are present in the same genomic locations across multiple strains of both species and display a level of divergence that is consistent with other shared regions between the genomes and with vertical inheritance of the locus, we refer to them broadly as “Pantailocins.” IMPORTANCE : Phage-derived bacteriocins (tailocins) are ribosomally synthesized structures produced by bacteria in order to provide advantages against competing strains under natural conditions. Tailocins are highly specific in their target range and have proven to be effective for the prevention and/or treatment of bacterial diseases under clinical and agricultural settings. We describe the discovery and characterization of a new tailocin locus encoded within genomes of Pantoea ananatis and Pantoea stewartii subsp. indologenes, which may enable the development of tailocins as preventative treatments against phytopathogenic infection by these species.National Science Foundation (NSF).https://journals.asm.org/journal/aemhj2024BiochemistryGeneticsMicrobiology and Plant PathologySDG-15:Life on lan

    Comparative Genomics of Multiple Strains of Pseudomonas cannabina pv. alisalensis, a Potential Model Pathogen of Both Monocots and Dicots

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    Comparative genomics of closely related pathogens that differ in host range can provide insights into mechanisms of host-pathogen interactions and host adaptation. Furthermore, sequencing of multiple strains with the same host range reveals information concerning pathogen diversity and the molecular basis of virulence. Here we present a comparative analysis of draft genome sequences for four strains of Pseudomonas cannabina pathovar alisalensis (Pcal), which is pathogenic on a range of monocotyledonous and dicotyledonous plants. These draft genome sequences provide a foundation for understanding host range evolution across the monocot-dicot divide. Like other phytopathogenic pseudomonads, Pcal strains harboured a hrp/hrc gene cluster that codes for a type III secretion system. Phylogenetic analysis based on the hrp/hrc cluster genes/proteins, suggests localized recombination and functional divergence within the hrp/hrc cluster. Despite significant conservation of overall genetic content across Pcal genomes, comparison of type III effector repertoires reinforced previous molecular data suggesting the existence of two distinct lineages within this pathovar. Furthermore, all Pcal strains analyzed harbored two distinct genomic islands predicted to code for type VI secretion systems (T6SSs). While one of these systems was orthologous to known P. syringae T6SSs, the other more closely resembled a T6SS found within P. aeruginosa. In summary, our study provides a foundation to unravel Pcal adaptation to both monocot and dicot hosts and provides genetic insights into the mechanisms underlying pathogenicity
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