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Erhard Bremer - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and uptake of the compatible solutes ectoine and 5-hydroxyectoine by Streptomyces coelicolor A3(2) in response to salt and heat stresses.
Applied and Environmental Microbiology, 2008Co-Authors: Jan Bursy, Anne U Kuhlmann, Marco Pittelkow, Holger Hartmann, Antonio J Pierik, Erhard BremerAbstract:Streptomyces coelicolor A3(2) synthesizes ectoine and 5-hydroxyectoine upon the imposition of either salt (0.5 M NaCl) or heat stress (39 degrees C). The cells produced the highest cellular levels of these compatible solutes when both stress conditions were simultaneously imposed. Protection against either severe salt (1.2 M NaCl) or heat stress (39 degrees C) or a combination of both environmental cues could be accomplished by adding low concentrations (1 mM) of either ectoine or 5-hydroxyectoine to S. coelicolor A3(2) cultures. The best salt and heat stress protection was observed when a mixture of ectoine and 5-hydroxyectoine (0.5 mM each) was provided to the growth medium. Transport assays with radiolabeled ectoine demonstrated that uptake was triggered by either salt or heat stress. The most effective transport and accumulation of [(14)C]ectoine by S. coelicolor A3(2) were achieved when both environmental cues were simultaneously applied. Our results demonstrate that the accumulation of the compatible solutes ectoine and 5-hydroxyectoine allows S. coelicolor A3(2) to fend off the detrimental effects of both high salinity and high temperature on cell physiology. We also characterized the enzyme (EctD) required for the synthesis of 5-hydroxyectoine from ectoine, a hydroxylase of the superfamily of the non-heme-containing iron(II)- and 2-oxoglutarate-dependent dioxygenases (EC 1.14.11). The gene cluster (ectABCD) encoding the enzymes for ectoine and 5-hydroxyectoine biosynthesis can be found in the genome of S. coelicolor A3(2), Streptomyces avermitilis, Streptomyces griseus, Streptomyces Scabiei, and Streptomyces chrysomallus, suggesting that these compatible solutes play an important role as stress protectants in the genus Streptomyces.
Carole Beaulieu - One of the best experts on this subject based on the ideXlab platform.
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Habituation to thaxtomin A increases resistance to common scab in 'Russet Burbank' potato.
'Public Library of Science (PLoS)', 2021Co-Authors: Nathalie Beaudoin, Carole Beaulieu, Iauhenia Isayenka, Audrey Ducharme, Sophie Massie, André Gagnon, Richard Hogue, Dominique MichaudAbstract:Common scab is a potato disease characterized by the formation of scab-like lesions on the surface of potato tubers. The actinobacterium Streptomyces Scabiei is the main causal agent of common scab. During infection, this bacterium synthesizes the phytotoxin thaxtomin A which is essential for the production of disease symptoms. While thaxtomin A can activate an atypical programmed cell death in plant cell suspensions, it is possible to gradually habituate plant cells to thaxtomin A to provide resistance to lethal phytotoxin concentrations. Potato 'Russet Burbank' calli were habituated to thaxtomin A to regenerate the somaclone RB9 that produced tubers more resistant to common scab than those obtained from the original cultivar. Compared to the Russet Burbank cultivar, somaclone RB9 generated up to 22% more marketable tubers with an infected tuber area below the 5% threshold. Enhanced resistance was maintained over at least two years of cultivation in the field. However, average size of tubers was significantly reduced in somaclone RB9 compared to the parent cultivar. Small RB9 tubers had a thicker phellem than Russet Burbank tubers, which may contribute to improving resistance to common scab. These results show that thaxtomin A-habituation in potato is efficient to produce somaclones with increased and durable resistance to common scab
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suberin regulates the production of cellulolytic enzymes in Streptomyces Scabiei the causal agent of potato common scab
Microbes and Environments, 2015Co-Authors: Rebeca Padillareynaud, Sylvain Lerat, Mark A. Bernards, Annemarie Simaobeaunoir, Carole BeaulieuAbstract:Suberin, a major constituent of the potato periderm, is known to promote the production of thaxtomins, the key virulence factors of the common scab-causing agent Streptomyces Scabiei. In the present study, we speculated that suberin affected the production of glycosyl hydrolases, such as cellulases, by S. Scabiei, and demonstrated that suberin promoted glycosyl hydrolase activity when added to cellulose-, xylan-, or lichenin-containing media. Furthermore, secretome analyses revealed that the addition of suberin to a cellulose-containing medium increased the production of glycosyl hydrolases. For example, the production of 13 out of the 14 cellulases produced by S. Scabiei in cellulose-containing medium was stimulated by the presence of suberin. In most cases, the transcription of the corresponding cellulase-encoding genes was also markedly increased when the bacterium was grown in the presence of suberin and cellulose. The level of a subtilase-like protease inhibitor was markedly decreased by the presence of suberin. We proposed a model for the onset of S. Scabiei virulence mechanisms by both cellulose and suberin, the main degradation product of cellulose that acts as an inducer of thaxtomin biosynthetic genes, and suberin promoting the biosynthesis of secondary metabolites including thaxtomins.
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Potato Suberin Induces Differentiation and Secondary Metabolism in the Genus Streptomyces
2011Co-Authors: Sylvain Lerat, Carole Beaulieu, Gilles Grondin, Université De Sherbrooke, Martin Forest, Annie Lauzier, Serge LacelleAbstract:Bacteria of the genus Streptomyces are soil microorganisms with a saprophytic life cycle. Previous studies have revealed that the phytopathogenic agent S. Scabiei undergoes metabolic and morphological modifications in the presence of suberin, a complex plant polymer. This paper investigates morphological changes induced by the presence of potato suberin in five species of the genus Streptomyces, with emphasis on S. Scabiei. Streptomyces Scabiei, S. acidiscabies, S. avermitilis, S. coelicolor and S. melanosporofaciens were grown both in the presence and absence of suberin. In all species tested, the presence of the plant polymer induced the production of aerial hyphae and enhanced resistance to mechanical lysis. The presence of suberin in liquid minimal medium also induced the synthesis of typical secondary metabolites in S. Scabiei and S. acidiscabies (thaxtomin A), S. coelicolor (actinorhodin) and S. melanosporofaciens (geldanamycin). In S. Scabiei, the presence of suberin modified the fatty acid composition of the bacterial membrane, which translated into higher membrane fluidity. Moreover, suberin also induced thickening of the bacterial cell wall. The present data indicate that suberin hastens cellular differentiation and triggers the onset of secondary metabolism in the genus Streptomyces
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Streptomyces Scabiei and its toxin thaxtomin a induce scopoletin biosynthesis in tobacco and arabidopsis thaliana
Plant Cell Reports, 2009Co-Authors: Sylvain Lerat, Amadou H Babana, Mohamed El Oirdi, Abdelbassed El Hadrami, Kamal Bouarab, Nathalie Beaudoin, Fouad Daayf, Carole BeaulieuAbstract:Streptomyces Scabiei is the predominant causal agent of common scab of potato in North America. The virulence of common scab-causing streptomycetes relies on their capacity to synthesize thaxtomins. In this study, the effects of S. Scabiei infection and of thaxtomin A, the main toxin produced by S. Scabiei, were tested for the elicitation of plant defense molecules in the model plants tobacco (Nicotiana tabacum) and Arabidopsis thaliana. Tobacco leaves infected with spores of S. Scabiei strain EF-35 or infiltrated with purified thaxtomin A produced a blue fluorescent compound that was not detected in leaves infiltrated with spores of a S. Scabiei mutant deficient in thaxtomin A biosynthesis. Thin layer chromatography and high performance liquid chromatography identified this fluorescent compound as scopoletin, a plant defense phytoalexin. Arabidopsis seedlings grown in liquid medium also excreted scopoletin as a reaction to S. Scabiei and thaxtomin A. The effects of the presence of scopoletin on S. Scabiei were also investigated. The phytoalexin scopoletin caused a slight reduction of bacterial growth and a severe decrease of thaxtomin A production. Scopoletin was shown to inhibit thaxtomin A production by repression of a gene involved in the toxin biosynthesis.
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taxonomic study on nonpathogenic streptomycetes isolated from common scab lesions on potato tubers
Systematic and Applied Microbiology, 2001Co-Authors: Cyrlezin Doumbou, Vladimir Akimov, Melanie Cote, Pierremathieu Charest, Carole BeaulieuAbstract:Numerical analysis was carried out to compare sixteen nonpathogenic actinomycetes isolated from common scab lesions on potato tubers with Streptomyces Scabiei type strain as well as with other streptomycete groups. These isolates were divided into two classes according to their level of similarity with S. Scabiei. Isolates resembling S. Scabiei were associated with S. griseoruber or with S. violaceusniger while isolates exhibiting less than 61% of similarity with S. Scabiei were phenotypically related to S. albidoflavus or to S. atroolivaceus. Sequence of the 16S rRNA gene of each isolate was obtained and compared against the GenBank nucleotide database. No significant match could be established between the sequences of two potato isolates and the ones available in the GenBank database. The other isolates were closely related with S. setonii (S. griseus), S. mirabilis, S. fimbriatus, S. violaceoruber, S. melanosporofaciens and S. thermocarboxydus.
Dawn R D Bignell - One of the best experts on this subject based on the ideXlab platform.
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coronafacoyl phytotoxin biosynthesis and evolution in the common scab pathogen Streptomyces Scabiei
Applied and Environmental Microbiology, 2017Co-Authors: Luke Bown, Fabrice Berrue, Joost T P Verhoeven, Suzanne C Dufour, Dawn R D BignellAbstract:Coronafacoyl phytotoxins are an important family of plant toxins that are produced by several different phytopathogenic bacteria, including the gammaproteobacterium Pseudomonas syringae and the actinobacterium Streptomyces Scabiei (formerly Streptomyces scabies). The phytotoxins consist of coronafacic acid (CFA) linked via an amide bond to different amino acids or amino acid derivatives. Previous work suggested that S. Scabiei and P. syringae use distinct biosynthetic pathways for producing CFA, which is subsequently linked to its amino acid partner to form the complete phytotoxin. Here, we provide further evidence that the S. Scabiei CFA biosynthetic pathway is novel by characterizing the role of CYP107AK1, a predicted cytochrome P450 that has no homologue in P. syringae Deletion of the CYP107AK1 gene abolished production of coronafacoyl-isoleucine (CFA-Ile), the primary coronafacoyl phytotoxin produced by S. Scabiei Structural elucidation of accumulated biosynthetic intermediates in the ΔCYP107AK1 mutant indicated that CYP107AK1 is required for introducing the oxygen atom that ultimately forms the carbonyl group in the CFA backbone. The CYP107AK1 gene along with two additional genes involved in CFA-Ile biosynthesis in S. Scabiei were found to be associated with putative CFA biosynthetic genes in other actinobacteria but not in other organisms. Analysis of the overall genetic content and organization of known and putative CFA biosynthetic gene clusters, together with phylogenetic analysis of the core biosynthetic genes, indicates that horizontal gene transfer has played an important role in the dissemination of the gene cluster and that rearrangement, insertion, and/or deletion events have likely contributed to the divergent biosynthetic evolution of coronafacoyl phytotoxins in bacteria.IMPORTANCE The ability of plants to defend themselves against invading pathogens relies on complex signaling pathways that are controlled by key phytohormones such as jasmonic acid (JA). Some phytopathogenic bacteria have evolved the ability to manipulate JA signaling in order to overcome host defenses by producing coronatine (COR), which functions as a potent JA mimic. COR and COR-like molecules, collectively referred to as coronafacoyl phytotoxins, are produced by several different plant-pathogenic bacteria, and this study provides supporting evidence that different biosynthetic pathways are utilized by different bacteria for production of these phytotoxins. In addition, our study provides a greater understanding of how coronafacoyl phytotoxin biosynthesis may have evolved in phylogenetically distinct bacteria, and we demonstrate that production of these compounds may be more widespread than previously recognized and that their role for the producing organism may not be limited to host-pathogen interactions.
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promiscuous pathogenicity islands and phylogeny of pathogenic Streptomyces spp
Molecular Plant-microbe Interactions, 2016Co-Authors: Yucheng Zhang, Dawn R D Bignell, Ran Zuo, Qiurong Fan, Jose C Huguettapia, Yousong Ding, Rosemary LoriaAbstract:Approximately 10 Streptomyces species cause disease on underground plant structures. The most economically important of these is potato scab, and the most studied of these pathogens is Streptomyces Scabiei (syn. S. scabies). The main pathogenicity determinant of scab-causing Streptomyces species is a nitrated diketopiperazine, known as thaxtomin A (ThxA). In the pathogenic species Streptomyces turgidiscabies, ThxA biosynthetic genes reside on a mobile pathogenicity island (PAI). However, the mobilization of PAIs in other Streptomyces species remains uncharacterized. Here, we investigated the mobilization of the PAI of S. Scabiei 87-22. Based on whole genome sequences, we inferred the evolutionary relationships of pathogenic Streptomyces species and discovered that Streptomyces sp. strain 96-12, a novel pathogenic species isolated from potatoes in Egypt, was phylogenetically grouped with nonpathogenic species rather than with known pathogenic species. We also found that Streptomyces sp. strain 96-12 contains a PAI that is almost identical to the PAI in S. Scabiei 87-22, despite significant differences in their genome sequences. This suggested direct or indirect in vivo mobilization of the PAI between S. Scabiei and nonpathogenic Streptomyces species. To test whether the S. Scabiei 87-22 PAI could, indeed, be mobilized, S. Scabiei 87-22 deletion mutants containing antibiotic resistance markers in the PAI were mated with Streptomyces diastatochromogenes, a nonpathogenic species. The PAI of S. Scabiei was site-specifically inserted into the aviX1 gene of S. diastatochromogenes and conferred pathogenicity in radish seedling assays. Our results demonstrated that S. Scabiei, the earliest described Streptomyces pathogen, could be the source of a PAI responsible for the emergence of novel pathogenic species.
Jan Bursy - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and uptake of the compatible solutes ectoine and 5-hydroxyectoine by Streptomyces coelicolor A3(2) in response to salt and heat stresses.
Applied and Environmental Microbiology, 2008Co-Authors: Jan Bursy, Anne U Kuhlmann, Marco Pittelkow, Holger Hartmann, Antonio J Pierik, Erhard BremerAbstract:Streptomyces coelicolor A3(2) synthesizes ectoine and 5-hydroxyectoine upon the imposition of either salt (0.5 M NaCl) or heat stress (39 degrees C). The cells produced the highest cellular levels of these compatible solutes when both stress conditions were simultaneously imposed. Protection against either severe salt (1.2 M NaCl) or heat stress (39 degrees C) or a combination of both environmental cues could be accomplished by adding low concentrations (1 mM) of either ectoine or 5-hydroxyectoine to S. coelicolor A3(2) cultures. The best salt and heat stress protection was observed when a mixture of ectoine and 5-hydroxyectoine (0.5 mM each) was provided to the growth medium. Transport assays with radiolabeled ectoine demonstrated that uptake was triggered by either salt or heat stress. The most effective transport and accumulation of [(14)C]ectoine by S. coelicolor A3(2) were achieved when both environmental cues were simultaneously applied. Our results demonstrate that the accumulation of the compatible solutes ectoine and 5-hydroxyectoine allows S. coelicolor A3(2) to fend off the detrimental effects of both high salinity and high temperature on cell physiology. We also characterized the enzyme (EctD) required for the synthesis of 5-hydroxyectoine from ectoine, a hydroxylase of the superfamily of the non-heme-containing iron(II)- and 2-oxoglutarate-dependent dioxygenases (EC 1.14.11). The gene cluster (ectABCD) encoding the enzymes for ectoine and 5-hydroxyectoine biosynthesis can be found in the genome of S. coelicolor A3(2), Streptomyces avermitilis, Streptomyces griseus, Streptomyces Scabiei, and Streptomyces chrysomallus, suggesting that these compatible solutes play an important role as stress protectants in the genus Streptomyces.
Rosemary Loria - One of the best experts on this subject based on the ideXlab platform.
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genotypic and phenotypic characterization of Streptomyces species causing potato common scab in uruguay
Plant Disease, 2017Co-Authors: Maria Ines Lapaz, Rosemary Loria, Jose C Huguettapia, Maria Ines Siri, Enrique Verdier, Maria Julia PianzzolaAbstract:Isolation and characterization of common scab (CS) pathogen Streptomyces spp. from Uruguayan potato tubers and soil samples were done in response to significant economic losses due to CS on potato in autumn 2010. Seventy of the 331 isolates were classified as pathogenic owing to their ability to induce necrosis on tuber disks and stunting of radish seedling. Streptomyces spp. causing CS on potato in Uruguay were found to represent a range of different species by virtue of their diverse morphological and physiological traits as well as rep-PCR, rpoB phylogenetic analysis, and multi-locus sequences analysis. We identified isolates primarily as Streptomyces Scabiei, S. acidiscabies, and S. europaeiScabiei. However, some of the pathogenic isolates still remain to be identified at the species level. This highlights the need for improved methods for discrimination among pathogenic Streptomyces species. The presence of Streptomyces pathogenicity island (PAI) genes was analyzed, including genes encoding for thaxt...
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emergence of novel pathogenic Streptomyces species by site specific accretion and cis mobilization of pathogenicity islands
Molecular Plant-microbe Interactions, 2017Co-Authors: Yucheng Zhang, Rosemary LoriaAbstract:The main pathogenicity factor of Streptomyces species associated with the potato common scab disease is a nitrated diketopiperazine called thaxtomin A (ThxA). In Streptomyces Scabiei (syn. S. scabies), which is thought to be the most ancient pathogenic Streptomyces species, the ThxA biosynthetic cluster is located within a mobile genomic island called the toxicogenic region (TR). Three attachment (att) sites further separate TR into two subregions (TR1 and TR2). TR1 contains the ThxA biosynthetic cluster and is conserved among several pathogenic Streptomyces species. However, TR2, an integrative and conjugative element, is missing in most pathogenic species. In our previous study, we demonstrated the mobilization of the whole TR element or TR2 alone between S. Scabiei and nonpathogenic Streptomyces species. TR1 alone did not mobilize in these experiments. These data suggest that TR2 is required for the mobilization of TR1. Here, we show that TR2 can self mobilize to pathogenic Streptomyces species harboring only TR1 and integrate into the att site of TR1, leading to the tandem accretion of resident TR1 and incoming TR2. The incoming TR2 can further mobilize resident TR1 in cis and transfer to a new recipient cell. Our study demonstrated that TR1 is a nonautonomous cis-mobilizable element and that it can hijack TR2 recombination and conjugation machinery to excise, transfer, and integrate, leading to the dissemination of pathogenicity genes and emergence of novel pathogenic species. Additionally, comparative genomic analysis of 23 pathogenic Streptomyces isolates from ten species revealed that the composite pathogenicity island (PAI) formed by TR1 and TR2 is dynamic and various compositions of the island exist within the population of newly emerged pathogenic species, indicating the structural instability of this composite PAI.
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promiscuous pathogenicity islands and phylogeny of pathogenic Streptomyces spp
Molecular Plant-microbe Interactions, 2016Co-Authors: Yucheng Zhang, Dawn R D Bignell, Ran Zuo, Qiurong Fan, Jose C Huguettapia, Yousong Ding, Rosemary LoriaAbstract:Approximately 10 Streptomyces species cause disease on underground plant structures. The most economically important of these is potato scab, and the most studied of these pathogens is Streptomyces Scabiei (syn. S. scabies). The main pathogenicity determinant of scab-causing Streptomyces species is a nitrated diketopiperazine, known as thaxtomin A (ThxA). In the pathogenic species Streptomyces turgidiscabies, ThxA biosynthetic genes reside on a mobile pathogenicity island (PAI). However, the mobilization of PAIs in other Streptomyces species remains uncharacterized. Here, we investigated the mobilization of the PAI of S. Scabiei 87-22. Based on whole genome sequences, we inferred the evolutionary relationships of pathogenic Streptomyces species and discovered that Streptomyces sp. strain 96-12, a novel pathogenic species isolated from potatoes in Egypt, was phylogenetically grouped with nonpathogenic species rather than with known pathogenic species. We also found that Streptomyces sp. strain 96-12 contains a PAI that is almost identical to the PAI in S. Scabiei 87-22, despite significant differences in their genome sequences. This suggested direct or indirect in vivo mobilization of the PAI between S. Scabiei and nonpathogenic Streptomyces species. To test whether the S. Scabiei 87-22 PAI could, indeed, be mobilized, S. Scabiei 87-22 deletion mutants containing antibiotic resistance markers in the PAI were mated with Streptomyces diastatochromogenes, a nonpathogenic species. The PAI of S. Scabiei was site-specifically inserted into the aviX1 gene of S. diastatochromogenes and conferred pathogenicity in radish seedling assays. Our results demonstrated that S. Scabiei, the earliest described Streptomyces pathogen, could be the source of a PAI responsible for the emergence of novel pathogenic species.