Regulatory role of UvrY in adaptation of <i>Photorhabdus luminescens</i> growth inside the insect

Krin, Evelyne; Derzelle, Sylviane; Bédard, Karine; Adib‐Conquy, Minou; Turlin, Évelyne; Lenormand, Pascal; Hullo, Marie-Françoise; Bonne, Isabelle; Chakroun, Nesrine; Lacroix, Céline; Danchin, Antoine

doi:10.1111/j.1462-2920.2007.01528.x

Cited by 28 publications

(28 citation statements)

References 57 publications

(121 reference statements)

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“…Similar effects have already been reported for isogenic mutants displaying impaired production of the regulatory proteins HcaR, SodA, UvrY, and LuxS (17,43,44). Like VAR*, none of these four mutants displayed a complete lack of virulence.…”

Section: Vol 77 2011 Transcriptional Analysis Of a Photorhabdus Varsupporting

confidence: 64%

Transcriptional Analysis of a Photorhabdus sp. Variant Reveals Transcriptional Control of Phenotypic Variation and Multifactorial Pathogenicity in Insects

Lanois¹,

Pagès²,

Bourot

et al. 2011

Appl Environ Microbiol

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Photorhabdus luminescens lives in a mutualistic association with entomopathogenic nematodes and is pathogenic for insects. Variants of Photorhabdus frequently arise irreversibly and are studied because they have altered phenotypic traits that are potentially important for the host interaction. VAR* is a colonial and phenotypic variant displaying delayed pathogenicity when directly injected into the insect, Spodoptera littoralis. In this study, we evaluated the role of transcriptomic modulation in determining the phenotypic variation and delayed pathogenicity of VAR* with respect to the corresponding wild-type form, TT01␣. A P. luminescens microarray identified 148 genes as differentially transcribed between VAR* and TT01␣. The net regulator status of VAR* was found to be significantly modified. We also observed in VAR* a decrease in the transcription of genes supporting certain phenotypic traits, such as pigmentation, crystalline inclusion, antibiosis, and protease and lipase activities. Three genes encoding insecticidal toxins (pit and pirB) or putative insecticidal toxins (xnp2) were less transcribed in VAR* than in the TT01␣. The overexpression of these genes was not sufficient to restore the virulence of VAR* to the levels of ⌻⌻01␣, which suggests that the lower virulence of VAR* does not result from impaired toxemia in insects. Three loci involved in oxidative stress responses (sodA, katE, and the hca operon) were found to be downregulated in VAR*. This is consistent with the greater sensitivity of VAR* to H 2 O 2 and may account for the impaired bacteremia in the hemolymph of S. littoralis larvae observed with VAR*. In conclusion, we demonstrate here that some phenotypic traits of VAR* are regulated transcriptionally and highlight the multifactorial nature of pathogenicity in insects.Photorhabdus luminescens is a member of the Enterobacteriaceae that lives in a mutualistic association with entomopathogenic nematodes and is pathogenic for a wide range of insects. Studies on Photorhabdus pathogenicity have shown this bacterium to be highly virulent, due to the production of an array of insecticidal toxins and the induction of host immune depression (6,18, 25,28,41,67).

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Section: Vol 77 2011 Transcriptional Analysis Of a Photorhabdus Varsupporting

confidence: 64%

Transcriptional Analysis of a Photorhabdus sp. Variant Reveals Transcriptional Control of Phenotypic Variation and Multifactorial Pathogenicity in Insects

Lanois¹,

Pagès²,

Bourot

et al. 2011

Appl Environ Microbiol

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“…Functional homologs of the Csr/Rsm system have been discovered in many Gram-negative bacteria, including Escherichia (21), Salmonella (11), Vibrio (20), Yersinia (14), Azotobacter (7), Acinetobacter (8), Erwinia (22), Serratia (29), and Photorhabdus (17). Although these bacteria possess a functional Csr/Rsm system, Csr/Rsm sRNAs are not systematically located between mutS and rpoS (Table 1), which is a unique feature in gammaproteobacteria.…”

Section: Resultsmentioning

confidence: 99%

Multiple Transcription-Activating Sequences Regulate the RsmZ Regulatory Small RNA of Pseudomonas brassicacearum

Lalaouna¹,

Fochesato²,

Barakat³

et al. 2012

J. Bacteriol.

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The mutS-rpoS region is known to be a highly polymorphic segment of the chromosome owing to horizontal gene transfer and evolutionary processes. In Pseudomonas, mutS-fdxA-rsmZ-rpoS organization is highly conserved, as well as the promoter region of the RsmZ small RNA (sRNA)-encoding gene. One exception to this conservation is in Pseudomonas brassicacearum, where a 308-nucleotide (nt) sequence, predicted to form a hairpin structure in single-stranded DNA (ssDNA), is inserted between the rpoS and rsmZ genes. Using MEME software, we identified nine consensus motifs in the rsmZ promoter region of 16 sequenced Pseudomonas genomes. We observed that an upstream activation sequence (UAS) and an M1 motif (located between the ؊10 promoter element and the UAS) are shared among examined Pseudomonas genomes. A third motif, the M2 motif, is localized within the coding sequence of the rpoS gene. Constructs fusing the different identified motifs to the lacZ reporter were produced. Our in vivo analysis of the rsmZ-activating elements indicates that the palindromic UAS located 180 bp upstream of the rsmZ transcriptional start in P. brassicacearum NFM 421 is essential, but not sufficient, for full rsmZ expression. Here, we demonstrate a role for the three motifs in the activation of the rsmZ gene, and we hypothesize the role of additional transcriptional factors, along with the DNA structuring role of the hairpin in the complex network controlling the expression of rsmZ.

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“…Homologues of the BarA-UvrY TCS system also regulate CsrA activity in other bacterial species via sRNAs [85,127,[132][133][134][135]. Microarray analysis was performed in P. luminescens to identify genes controlled by this TCS [133].…”

Section: Regulation By the Csrb And Csrc Srnasmentioning

confidence: 99%

Post-transcriptional global regulation by CsrA in bacteria

Timmermans

Melderen

2010

Cell. Mol. Life Sci.

154

177

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Global regulation allows bacteria to rapidly modulate the expression of a large variety of unrelated genes in response to environmental changes. Global regulators act at different levels of gene expression. This review focuses on CsrA, a post-transcriptional regulator that affects translation of its gene targets by binding mRNAs. CsrA controls a large variety of physiological processes such as central carbon metabolism, motility and biofilm formation. The activity of CsrA is itself tightly regulated by the CsrB and CsrC small RNAs and the BarA-UvrY two-component system.

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Regulatory role of UvrY in adaptation of Photorhabdus luminescens growth inside the insect

Cited by 28 publications

References 57 publications

Transcriptional Analysis of a Photorhabdus sp. Variant Reveals Transcriptional Control of Phenotypic Variation and Multifactorial Pathogenicity in Insects

Transcriptional Analysis of a Photorhabdus sp. Variant Reveals Transcriptional Control of Phenotypic Variation and Multifactorial Pathogenicity in Insects

Multiple Transcription-Activating Sequences Regulate the RsmZ Regulatory Small RNA of Pseudomonas brassicacearum

Post-transcriptional global regulation by CsrA in bacteria

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