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van der Lee TAJ, van Gent-Pelzer MPE, Jonkheer EM, Brankovics B, Houwers IM, van der Wolf JM, Bonants PJM, van Duivenbode I, Vreeburg RAM, Nas M, Smit S. An Efficient Triplex TaqMan Quantitative PCR to Detect a Blackleg-Causing Lineage of Pectobacterium brasiliense in Potato Based on a Pangenome Analysis. Microorganisms 2023; 11:2080. [PMID: 37630640 PMCID: PMC10459533 DOI: 10.3390/microorganisms11082080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 08/08/2023] [Accepted: 08/10/2023] [Indexed: 08/27/2023] Open
Abstract
P. brasiliense is an important bacterial pathogen causing blackleg (BL) in potatoes. Nevertheless, P. brasiliense is often detected in seed lots that do not develop any of the typical blackleg symptoms in the potato crop when planted. Field bioassays identified that P. brasiliense strains can be categorized into two distinct classes, some able to cause blackleg symptoms and some unable to do it. A comparative pangenomic approach was performed on 116 P. brasiliense strains, of which 15 were characterized as BL-causing strains and 25 as non-causative. In a genetically homogeneous clade comprising all BL-causing P. brasiliense strains, two genes only present in the BL-causing strains were identified, one encoding a predicted lysozyme inhibitor Lprl (LZI) and one encoding a putative Toll/interleukin-1 receptor (TIR) domain-containing protein. TaqMan assays for the specific detection of BL-causing P. brasiliense were developed and integrated with the previously developed generic P. brasiliense assay into a triplex TaqMan assay. This simultaneous detection makes the scoring more efficient as only a single tube is needed, and it is more robust as BL-causing strains of P. brasiliense should be positive for all three assays. Individual P. brasiliense strains were found to be either positive for all three assays or only for the P. brasiliense assay. In potato samples, the mixed presence of BL-causing and not BL-causing P. brasiliense strains was observed as shown by the difference in Ct value of the TaqMan assays. However, upon extension of the number of strains, it became clear that in recent years additional BL-causing lineages of P. brasiliense were detected for which additional assays must be developed.
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Affiliation(s)
- Theo A. J. van der Lee
- Biointeractions and Plant Health, Wageningen Plant Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Marga P. E. van Gent-Pelzer
- Biointeractions and Plant Health, Wageningen Plant Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Eef M. Jonkheer
- Biointeractions and Plant Health, Wageningen Plant Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
- Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Balázs Brankovics
- Biointeractions and Plant Health, Wageningen Plant Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Ilse M. Houwers
- Biointeractions and Plant Health, Wageningen Plant Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Jan M. van der Wolf
- Biointeractions and Plant Health, Wageningen Plant Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Peter J. M. Bonants
- Biointeractions and Plant Health, Wageningen Plant Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Inge van Duivenbode
- Dutch General Inspection Service (NAK), Randweg 14, 8304 AS Emmeloord, The Netherlands
| | - Robert A. M. Vreeburg
- Dutch General Inspection Service (NAK), Randweg 14, 8304 AS Emmeloord, The Netherlands
| | - Mathijs Nas
- Dutch General Inspection Service (NAK), Randweg 14, 8304 AS Emmeloord, The Netherlands
| | - Sandra Smit
- Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
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Jonkheer EM, Brankovics B, Houwers IM, van der Wolf JM, Bonants PJM, Vreeburg RAM, Bollema R, de Haan JR, Berke L, Smit S, de Ridder D, van der Lee TAJ. The Pectobacterium pangenome, with a focus on Pectobacterium brasiliense, shows a robust core and extensive exchange of genes from a shared gene pool. BMC Genomics 2021; 22:265. [PMID: 33849459 PMCID: PMC8045196 DOI: 10.1186/s12864-021-07583-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/26/2021] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Bacterial plant pathogens of the Pectobacterium genus are responsible for a wide spectrum of diseases in plants, including important crops such as potato, tomato, lettuce, and banana. Investigation of the genetic diversity underlying virulence and host specificity can be performed at genome level by using a comprehensive comparative approach called pangenomics. A pangenomic approach, using newly developed functionalities in PanTools, was applied to analyze the complex phylogeny of the Pectobacterium genus. We specifically used the pangenome to investigate genetic differences between virulent and avirulent strains of P. brasiliense, a potato blackleg causing species dominantly present in Western Europe. RESULTS Here we generated a multilevel pangenome for Pectobacterium, comprising 197 strains across 19 species, including type strains, with a focus on P. brasiliense. The extensive phylogenetic analysis of the Pectobacterium genus showed robust distinct clades, with most detail provided by 452,388 parsimony-informative single-nucleotide polymorphisms identified in single-copy orthologs. The average Pectobacterium genome consists of 47% core genes, 1% unique genes, and 52% accessory genes. Using the pangenome, we zoomed in on differences between virulent and avirulent P. brasiliense strains and identified 86 genes associated to virulent strains. We found that the organization of genes is highly structured and linked with gene conservation, function, and transcriptional orientation. CONCLUSION The pangenome analysis demonstrates that evolution in Pectobacteria is a highly dynamic process, including gene acquisitions partly in clusters, genome rearrangements, and loss of genes. Pectobacterium species are typically not characterized by a set of species-specific genes, but instead present themselves using new gene combinations from the shared gene pool. A multilevel pangenomic approach, fusing DNA, protein, biological function, taxonomic group, and phenotypes, facilitates studies in a flexible taxonomic context.
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Affiliation(s)
- Eef M Jonkheer
- Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
- Biointeractions and Plant Health, Wageningen Plant Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
| | - Balázs Brankovics
- Biointeractions and Plant Health, Wageningen Plant Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Ilse M Houwers
- Biointeractions and Plant Health, Wageningen Plant Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Jan M van der Wolf
- Biointeractions and Plant Health, Wageningen Plant Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Peter J M Bonants
- Biointeractions and Plant Health, Wageningen Plant Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Robert A M Vreeburg
- Nederlandse Algemene Keuringsdienst voor zaaizaad en pootgoed van landbouwgewassen, Randweg 14, 8304 AS, Emmeloord, The Netherlands
| | - Robert Bollema
- Nederlandse Algemene Keuringsdienst voor zaaizaad en pootgoed van landbouwgewassen, Randweg 14, 8304 AS, Emmeloord, The Netherlands
| | - Jorn R de Haan
- Genetwister Technologies B.V, Nieuwe Kanaal 7b, 6709 PA, Wageningen, The Netherlands
| | - Lidija Berke
- Genetwister Technologies B.V, Nieuwe Kanaal 7b, 6709 PA, Wageningen, The Netherlands
| | - Sandra Smit
- Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Dick de Ridder
- Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Theo A J van der Lee
- Biointeractions and Plant Health, Wageningen Plant Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
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