The stringent response regulator (p)ppGpp mediates virulence gene expression and survival in Erwinia amylovora
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ABSTRACT:
ORGANISM(S): Erwinia amylovora
PROVIDER: GSE143324 | GEO | 2020/03/23
REPOSITORIES: GEO
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2021-12-02 | GSE162090 | GEO
Project description:The bacterial pathogen Erwinia amylovora is the causal agent of fire blight, an economically significant disease of apple and pear. Disease initiation by E. amylovora requires the translocation of effector proteins into host cells by the hypersensitive response and pathogenicity (hrp) type III secretion system (T3SS). The alternate sigma factor HrpL positively regulates the transcription of structural and translocated components of the T3SS via hrp promoter elements. To characterize genome-wide hrpL-dependent gene expression in E. amylovora Ea1189, wild-type and Ea1189hrpL strains were cultured in hrp-inducing minimal medium, and total RNA was compared using a custom microarray designed to represent the annotated genes of E. amylovora ATCC 49946. Results revealed 24 genes differentially-regulated in Ea1189hrpL compared to Ea1189 with fold-change expression ratios greater than 1.5; of these, the expression of 19 genes was up-regulated while five genes exhibited negative regulation. To expand our understanding of the HrpL regulon and to elucidate direct versus indirect hrpL-mediated effects on gene expression, the genome of E. amylovora ATCC 49946 was examined in silico using a hidden Markov model assembled from known Erwinia spp. hrp promoters. This technique identified 21 putative type III novel hrp promoters; of these, 8+ were validated with quantitative polymerase chain reaction based on expression analyses. In total, hrpL-regulated genes encode all known components of the hrp T3SS and 5 putative type III effectors. Eight genes displayed apparent indirect hrpL regulation suggesting that the hrpL regulon is connected to downstream signaling networks. Construction of deletion mutants of three novel hrpL-regulated genes has resulted in the identification of additional virulence factors in E. amylovora as well as mutants displaying abnormal motility and biofilm phenotypes.
2012-03-28 | E-TABM-1137 | biostudies-arrayexpress
Project description:Microarray analysis of E. amylovora treated with compounds no. 3 and no. 9 identified a total of 588 significantly differentially expressed genes. Among them, 95 and 78 genes were, respectively, induced and suppressed by both compounds as compared to DMSO control. Majority of T3SS genes in E. amylovora including hrpL and avrRpt2 effector gene were suppressed by both compounds. Compound no. 3 also suppressed the transcription of amylovoran precursor and biosynthesis genes. On the other hand, both compounds significantly induced expression of glycogen biosynthesis genes and siderophore biosynthesis, regulatory and transport genes. Furthermore, many membrane, lipoprotein and exported protein encoding genes were also activated by both compounds.
2013-12-24 | GSE45602 | GEO
Project description:This RNA-seq analysis examined the global effect of CsrA and its non-coding small RNA (ncsRNA) csrB in E. amylovora under the T3SS-inducing condition. The csrA mutant showed differential expression of more than 20% genes in the genome, which include significant down-regulation of T3SS genes and those required for cell growth and viability. On the other hand, the csrB mutant exhibited significant up-regulation of most major virulence genes, suggesting antagonistic effect of csrB on CsrA targets.
2019-08-21 | GSE128088 | GEO
Project description:Microarray analysis of E. amylovora treated with compounds no. 3 and no. 9 identified a total of 588 significantly differentially expressed genes. Among them, 95 and 78 genes were, respectively, induced and suppressed by both compounds as compared to DMSO control. Majority of T3SS genes in E. amylovora including hrpL and avrRpt2 effector gene were suppressed by both compounds. Compound no. 3 also suppressed the transcription of amylovoran precursor and biosynthesis genes. On the other hand, both compounds significantly induced expression of glycogen biosynthesis genes and siderophore biosynthesis, regulatory and transport genes. Furthermore, many membrane, lipoprotein and exported protein encoding genes were also activated by both compounds. Erwinia amylovora WT strain treated with compound No. 3 and No. 9 and compared to DMSO control. Four biological replicates for each chemical treatment (two samples were combined) were hybridized to three arrays. Four biological replicates (two each combined) for DMSO treatment were hybridized to two arrays.
2013-12-24 | E-GEOD-45602 | biostudies-arrayexpress
Project description:We conducted genome-wide microarray analyses to determine the regulons of RcsB and RcsC in liquid medium and, for the first time, on immature pear fruit. Our array analyses identified a total of 648 genes differentially regulated by the RcsCB in vitro and in vivo. Consistent with our previous findings, RcsB acts as a positive regulator in both conditions, while RcsC positively controls amylovoran biosynthetic gene expression in vivo, but negatively in vitro. Besides amylovoran biosynthesis and regulatory genes, cell wall and cell envelope (membrane) as well as regulatory genes were the major components of the RcsBC regulon, including many novel genes. In addition, we have also demonstrated that transcripts of rcsA, rcsC and rcsD genes, but not rcsB gene, were up-regulated when grown in minimal medium or after infection of pear fruits compared to LB medium. Furthermore, a hidden Markov model (HMM) has predicted 60 genes with candidate RcsB binding site in the intergenic regions of the E. amylovora ATCC 49946 genome and 18 (28) of them were identified in the microarray assay. Based on our findings, a working model has been proposed to illustrate how the Rcs phosphorelay system regulates virulence gene expression in E. amylovora. A total of 12 samples were analyzed in two conditions: For in vitro condition (MBMA medium + 1% sorbitol), Erwinia amylovora wild type strain (2 replicates); E. amylovora rcsB mutant strain (2 replicates); E. amylovora rcsC mutant strain (2 replicates): For in vivo condition (on wounded immature pear fruits), Erwinia amylovora wild type strain (2 replicates); E. amylovora rcsB mutant strain (2 replicates); E. amylovora rcsC mutant strain (2 replicates).
2012-02-18 | E-GEOD-30751 | biostudies-arrayexpress
Project description:The stringent response regulator (p)ppGpp mediates virulence gene expression and survival in Erwinia amylovora
| PRJNA600018 | ENA
Project description:We conducted genome-wide microarray analyses to determine the regulons of RcsB and RcsC in liquid medium and, for the first time, on immature pear fruit. Our array analyses identified a total of 648 genes differentially regulated by the RcsCB in vitro and in vivo. Consistent with our previous findings, RcsB acts as a positive regulator in both conditions, while RcsC positively controls amylovoran biosynthetic gene expression in vivo, but negatively in vitro. Besides amylovoran biosynthesis and regulatory genes, cell wall and cell envelope (membrane) as well as regulatory genes were the major components of the RcsBC regulon, including many novel genes. In addition, we have also demonstrated that transcripts of rcsA, rcsC and rcsD genes, but not rcsB gene, were up-regulated when grown in minimal medium or after infection of pear fruits compared to LB medium. Furthermore, a hidden Markov model (HMM) has predicted 60 genes with candidate RcsB binding site in the intergenic regions of the E. amylovora ATCC 49946 genome and 18 (28) of them were identified in the microarray assay. Based on our findings, a working model has been proposed to illustrate how the Rcs phosphorelay system regulates virulence gene expression in E. amylovora.
2012-02-18 | GSE30751 | GEO
Project description:BackgroundThe nucleotide second messengers, i.e., guanosine tetraphosphate and pentaphosphate [collectively referred to as (p) ppGpp], trigger the stringent response under nutrient starvation conditions and play an essential role in virulence in the fire blight pathogen Erwinia amylovora. Here, we present transcriptomic analyses to uncover the overall effect of (p) ppGpp-mediated stringent response in E. amylovora in the hrp-inducing minimal medium (HMM).ResultsIn this study, we investigated the transcriptomic changes of the (p) ppGpp0 mutant under the type III secretion system (T3SS)-inducing condition using RNA-seq. A total of 1314 differentially expressed genes (DEGs) was uncovered, representing more than one third (36.8%) of all genes in the E. amylovora genome. Compared to the wild-type, the (p) ppGpp0 mutant showed down-regulation of genes involved in peptide ATP-binding cassette (ABC) transporters and virulence-related processes, including type III secretion system (T3SS), biofilm, and motility. Interestingly, in contrast to previous reports, the (p) ppGpp0 mutant showed up-regulation of amino acid biosynthesis genes, suggesting that it might be due to that these amino acid biosynthesis genes are indirectly regulated by (p) ppGpp in E. amylovora or represent specific culturing condition used. Furthermore, the (p) ppGpp0 mutant exhibited up-regulation of genes involved in translation, SOS response, DNA replication, chromosome segregation, as well as biosynthesis of nucleotide, fatty acid and lipid.ConclusionThese findings suggested that in HMM environment, E. amylovora might use (p) ppGpp as a signal to activate virulence gene expression, and simultaneously mediate the balance between virulence and survival by negatively regulating DNA replication, translation, cell division, as well as biosynthesis of nucleotide, amino acid, fatty acid, and lipid. Therefore, (p) ppGpp could be a promising target for developing novel control measures to fight against this devastating disease of apples and pears.
| S-EPMC7106674 | biostudies-literature
Project description:Microarray analysis was used to identify genes that were controlled by AmyR in minimal and on immature pear fruits. Consistent with amylovoran production, an inverse correlation was observed between amyR expression and the expression level of amylovoran biosynthetic genes in liquid media. Interestingly, over-expression of AmyR suppressed the expression of type III secretion system genes including hrpA, hrpN and dspEF after pear fruit infection. Consistent with levan production and swarming motility, levasucrase and flagellar genes were both down-regulated both in the amyR mutant and over-expression strains in liquid media. Together, our results suggest that AmyR plays an important role in regulating bacterial exopolysaccharide production and virulence in E. amylovora. A total of 14 samples were analyzed in two conditions: For the in vitro condition (MBMA medium + 1% sorbitol), Erwinia amylovora wild type strain (2 replicates); E. amylovora amyR mutant strain (3 replicates); E. amylovora amyR over-expression strain (3 replicates); For the in vivo condition (on wounded immature pear fruits), Erwinia amylovora wild type strain (2 replicates); E. amylovora amyR mutant strain (2 replicates); E. amylovora amyR over-expression strain (2 replicates).
2013-01-01 | E-GEOD-37064 | biostudies-arrayexpress