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The Leucine-Responsive Regulatory Protein Lrp Participates in Virulence Regulation Downstream of Small RNA ArcZ in Erwinia amylovora

Erwinia amylovora causes the devastating fire blight disease of apple and pear trees. During systemic infection of host trees, pathogen cells must rapidly respond to changes in their environment as they move through different host tissues that present distinct challenges and sources of nutrition. Gr...

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Autores principales: Schachterle, Jeffrey K., Sundin, George W.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Society for Microbiology 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6538786/
https://www.ncbi.nlm.nih.gov/pubmed/31138749
http://dx.doi.org/10.1128/mBio.00757-19
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author Schachterle, Jeffrey K.
Sundin, George W.
author_facet Schachterle, Jeffrey K.
Sundin, George W.
author_sort Schachterle, Jeffrey K.
collection PubMed
description Erwinia amylovora causes the devastating fire blight disease of apple and pear trees. During systemic infection of host trees, pathogen cells must rapidly respond to changes in their environment as they move through different host tissues that present distinct challenges and sources of nutrition. Growing evidence indicates that small RNAs (sRNAs) play an important role in disease progression as posttranscriptional regulators. The sRNA ArcZ positively regulates the motility phenotype and transcription of flagellar genes in E. amylovora Ea1189 yet is a direct repressor of translation of the flagellar master regulator, FlhD. We utilized transposon mutagenesis to conduct a forward genetic screen and identified suppressor mutations that increase motility in the Ea1189ΔarcZ mutant background. This enabled us to determine that the mechanism of transcriptional activation of the flhDC mRNA by ArcZ is mediated by the leucine-responsive regulatory protein, Lrp. We show that Lrp contributes to expression of virulence and several virulence-associated traits, including production of the exopolysaccharide amylovoran, levansucrase activity, and biofilm formation. We further show that Lrp is regulated posttranscriptionally by ArcZ through destabilization of lrp mRNA. Thus, ArcZ regulation of FlhDC directly and indirectly through Lrp forms an incoherent feed-forward loop that regulates levansucrase activity and motility as outputs. This work identifies Lrp as a novel participant in virulence regulation in E. amylovora and places it in the context of a virulence-associated regulatory network.
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spelling pubmed-65387862019-06-03 The Leucine-Responsive Regulatory Protein Lrp Participates in Virulence Regulation Downstream of Small RNA ArcZ in Erwinia amylovora Schachterle, Jeffrey K. Sundin, George W. mBio Research Article Erwinia amylovora causes the devastating fire blight disease of apple and pear trees. During systemic infection of host trees, pathogen cells must rapidly respond to changes in their environment as they move through different host tissues that present distinct challenges and sources of nutrition. Growing evidence indicates that small RNAs (sRNAs) play an important role in disease progression as posttranscriptional regulators. The sRNA ArcZ positively regulates the motility phenotype and transcription of flagellar genes in E. amylovora Ea1189 yet is a direct repressor of translation of the flagellar master regulator, FlhD. We utilized transposon mutagenesis to conduct a forward genetic screen and identified suppressor mutations that increase motility in the Ea1189ΔarcZ mutant background. This enabled us to determine that the mechanism of transcriptional activation of the flhDC mRNA by ArcZ is mediated by the leucine-responsive regulatory protein, Lrp. We show that Lrp contributes to expression of virulence and several virulence-associated traits, including production of the exopolysaccharide amylovoran, levansucrase activity, and biofilm formation. We further show that Lrp is regulated posttranscriptionally by ArcZ through destabilization of lrp mRNA. Thus, ArcZ regulation of FlhDC directly and indirectly through Lrp forms an incoherent feed-forward loop that regulates levansucrase activity and motility as outputs. This work identifies Lrp as a novel participant in virulence regulation in E. amylovora and places it in the context of a virulence-associated regulatory network. American Society for Microbiology 2019-05-28 /pmc/articles/PMC6538786/ /pubmed/31138749 http://dx.doi.org/10.1128/mBio.00757-19 Text en Copyright © 2019 Schachterle and Sundin. https://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Research Article
Schachterle, Jeffrey K.
Sundin, George W.
The Leucine-Responsive Regulatory Protein Lrp Participates in Virulence Regulation Downstream of Small RNA ArcZ in Erwinia amylovora
title The Leucine-Responsive Regulatory Protein Lrp Participates in Virulence Regulation Downstream of Small RNA ArcZ in Erwinia amylovora
title_full The Leucine-Responsive Regulatory Protein Lrp Participates in Virulence Regulation Downstream of Small RNA ArcZ in Erwinia amylovora
title_fullStr The Leucine-Responsive Regulatory Protein Lrp Participates in Virulence Regulation Downstream of Small RNA ArcZ in Erwinia amylovora
title_full_unstemmed The Leucine-Responsive Regulatory Protein Lrp Participates in Virulence Regulation Downstream of Small RNA ArcZ in Erwinia amylovora
title_short The Leucine-Responsive Regulatory Protein Lrp Participates in Virulence Regulation Downstream of Small RNA ArcZ in Erwinia amylovora
title_sort leucine-responsive regulatory protein lrp participates in virulence regulation downstream of small rna arcz in erwinia amylovora
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6538786/
https://www.ncbi.nlm.nih.gov/pubmed/31138749
http://dx.doi.org/10.1128/mBio.00757-19
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