Functional characterization of a global virulence regulator Hfq and identification of Hfq-dependent sRNAs in the plant pathogen Pantoea ananatis

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dc.contributor.author Shin, Giyoon
dc.contributor.author Schachterle, Jeffrey K.
dc.contributor.author Jeffrey K. Schachterle
dc.contributor.author Moleleki, Lucy Novungayo
dc.contributor.author Coutinho, Teresa A.
dc.contributor.author Sundin, George W.
dc.date.accessioned 2020-08-18T07:27:07Z
dc.date.available 2020-08-18T07:27:07Z
dc.date.issued 2019-09-11
dc.description Figure S1 : Southern blot validation of hfq knock-out mutation in Pantoea ananatis. Genomic DNA of the wild-type (WT) and hfq mutant (1hfq) strains of P. ananatis LMG 2665T digested with EcoRI and HindIII restriction enzymes was hybridized to a DIG-labeled probe (a partial amplicon of kanamycin resistance gene). Positive detection of the antibiotic marker was observed in the 1hfq strains of P. ananatis LMG 2665T (lanes 2–8). WT of P. ananatis LMG 2665T DNA was used as a negative control (lane 1) whereas unlabeled probe was used as a positive control (lane 9). en_ZA
dc.description Figure S2 : Colony PCR verification of hfq knock-out mutation in Pantoea ananatis. A colony PCR confirmation of insertion of kanamycin resistance gene in the hfq gene region using Test primers (Table 2) hfq mutant (1hfq) strains of P. ananatis LMG 2665T. L represents a molecular ladder and the sizes of its prominent bands 1, 3, and 6 kilo basepairs (kb) are indicated below. A wild-type (WT) colony of P. ananatis LMG 2665T was used as a negative control (lane 1; 500 bp). Insertion of kanamycin resistance marker is shown in colony PCRs of hfq mutant (1hfq) strains of P. ananatis LMG 2665T (lanes 2, 3, and 4; 1.5 kb). en_ZA
dc.description Figure S3 : In vitro growth assay. Growths of wild-type (WT), hfq mutant (1hfq), and hfq complementing (1hfq pBBR1MCS::hfq) strains of Pantoea ananatis LMG 2665T in LB broth at 28 C. The growth was monitored for 20 h at optical density 600 nm (OD600) and the mean OD600 readings of the three replicates for each P. ananatis LMG 2665T strains were plotted. Solid line (yellow) represents WT, dashed line (purple) 1hfq, and dotted line (green) 1hfq pBBR1MCS::hfq. Asterisks denote significance differences (P < 0.05) in the absorbance of 1hfq relative to WT P. ananatis LMG 2665T. en_ZA
dc.description Figure S4 : In planta growth assay. (A) Disease progression in onion scales inoculated with wild-type (WT), hfq mutant (1hfq), and hfq complementing [1hfq (pBBR1MCS::hfq)] strains of P. ananatis LMG 2665T, and incubated for 5 days post inoculation (dpi). (B) In planta populations of WT, 1hfq, and 1hfq (pBBR1MCS::hfq) strains of P. ananatis LMG 2665T in onion scales measured for 5 dpi. The mean CFUs of three replicates for each strain from two independent experiments were plotted. Solid line (yellow) represents WT, dashed line (purple) 1hfq, and dotted line (green) 1hfq (pBBR1MCS::hfq). en_ZA
dc.description Figure S5 : Logarithmic plot of the number of putative small RNAs (sRNAs) identified in Pantoea ananatis LMG 2665T (pPAR sRNA) as a function of the threshold selected for calling sRNAs. This was generated by calling putative sRNAs across a range of thresholds using the custom script (see Supplementary Data Sheet S1 in the section “peak_ID.py”). en_ZA
dc.description Figure S6 : In silico prediction of selected Pantoea ananatis sRNAs (pPAR sRNA) secondary structure. Secondary structures of P. ananatis LMG 2665T sRNAs (A) FnrS, (B) GlmZ, (C) pPAR 237, (D) pPAR 238, and (E) pPAR 395 were predicted based on a minimum free energy model provided by RNAfold (http://rna.tbi.univie.ac.at). en_ZA
dc.description Figure S7 : Putative interaction of pPAR237 and pPAR238 to eanIR in Pantoea ananatis LMG 2665T. (A) Location of pPAR237 and pPAR238. In silico predicted interaction of pPAR237 (red) to eanIR (black): (B) eanI upstream sequence (energy: 8.62323 kcal/mol; hybridization energy: 23.5). (C) eanR coding sequence (energy: 13.63700 kcal/mol, hybridization energy: 39.4) and (D) in silico predicted interaction of pPAR238 (red) to eanI (black) upstream sequence (energy: 7.83954 kcal/mol, hybridization energy: 12.0). en_ZA
dc.description Table S1 : Summary of sRNA sequencing reads obtained and filtered for use in sRNA identification. en_ZA
dc.description Table S2 : A list of sRNAs identified, their genomic coordinates, sequences, and selected characteristics. en_ZA
dc.description Table S3 : A list of sRNAs that has significant abundance difference between WT and hfq mutant strains of Pantoea ananatis. en_ZA
dc.description Table S4 : A list of predicted targets of selected sRNAs. en_ZA
dc.description Data Sheet S1 : A custom phython script compiled for bioinformatic analyses of sRNA sequencing data. en_ZA
dc.description.abstract To successfully infect plant hosts, the collective regulation of virulence factors in a bacterial pathogen is crucial. Hfq is an RNA chaperone protein that facilitates the small RNA (sRNA) regulation of global gene expression at the post-transcriptional level. In this study, the functional role of Hfq in a broad host range phytopathogen Pantoea ananatis was determined. Inactivation of the hfq gene in P. ananatis LMG 2665T resulted in the loss of pathogenicity and motility. In addition, there was a significant reduction of quorum sensing signal molecule acyl-homoserine lactone (AHL) production and biofilm formation. Differential sRNA expression analysis between the hfq mutant and wild-type strains of P. ananatis revealed 276 sRNAs affected in their abundance by the loss of hfq at low (OD600 = 0.2) and high cell (OD600 = 0.6) densities. Further analysis identified 25 Hfq-dependent sRNAs, all showing a predicted Rho-independent terminator of transcription and mapping within intergenic regions of the P. ananatis genome. These included known sRNAs such as ArcZ, FnrS, GlmZ, RprA, RyeB, RyhB, RyhB2, Spot42, and SsrA, and 16 novel P. ananatis sRNAs. The current study demonstrated that Hfq is an important component of the collective regulation of virulence factors and sets a foundation for understanding Hfq-sRNA mediated regulation in the phytopathogen P. ananatis. en_ZA
dc.description.department Biochemistry en_ZA
dc.description.department Forestry and Agricultural Biotechnology Institute (FABI) en_ZA
dc.description.department Genetics en_ZA
dc.description.department Microbiology and Plant Pathology en_ZA
dc.description.librarian am2020 en_ZA
dc.description.sponsorship The National Research Foundation (NRF) of South Africa, the University of Pretoria and the MSU AgBioResearch. en_ZA
dc.description.uri http://www.frontiersin.org/Microbiology en_ZA
dc.identifier.citation Shin GY, Schachterle JK, Shyntum DY, Moleleki LN, Coutinho TA and Sundin GW (2019) Functional Characterization of a Global Virulence Regulator Hfq and Identification of Hfq-Dependent sRNAs in the Plant Pathogen Pantoea ananatis. Frontiers in Microbiology 10:2075. DOI: 10.3389/fmicb.2019.02075. en_ZA
dc.identifier.issn 1664-302X (online)
dc.identifier.other 10.3389/fmicb.2019.02075
dc.identifier.uri http://hdl.handle.net/2263/75783
dc.language.iso en en_ZA
dc.publisher Frontiers Media en_ZA
dc.rights © 2019 Shin, Schachterle, Shyntum, Moleleki, Coutinho and Sundin. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). en_ZA
dc.subject Pantoea ananatis en_ZA
dc.subject Plant pathogen en_ZA
dc.subject Hfq en_ZA
dc.subject Regulation en_ZA
dc.subject Virulence en_ZA
dc.subject Small RNA (sRNA) en_ZA
dc.subject Acyl-homoserine lactone (AHL) en_ZA
dc.title Functional characterization of a global virulence regulator Hfq and identification of Hfq-dependent sRNAs in the plant pathogen Pantoea ananatis en_ZA
dc.type Article en_ZA


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