Heterogenicity within the LPS Structure in Relation to the Chosen Genomic and Physiological Features of the Plant Pathogen Pectobacterium parmentieri

Abstract

Pectobacterium parmentieri is a pectinolytic plant pathogenic bacterium causing high economic losses of cultivated plants. The highly devastating potential of this phytopathogen results from the efficient production of plant cell wall-degrading enzymes, i.e., pectinases, cellulases and proteases, in addition to the impact of accessory virulence factors such as motility, siderophores, biofilm and lipopolysaccharide (LPS). LPS belongs to pathogen-associated molecular patterns (PAMPs) and plays an important role in plant colonization and interaction with the defense systems of the host. Therefore, we decided to investigate the heterogeneity of O-polysaccharides (OPS) of LPS of different strains of P. parmentieri, in search of an association between the selected genomic and phenotypic features of the strains that share an identical structure of the OPS molecule. In the current study, OPS were isolated from the LPS of two P. parmentieri strains obtained either in Finland in the 1980s (SCC3193) or in Poland in 2013 (IFB5432). The purified polysaccharides were analyzed by utilizing 1D and 2D NMR spectroscopy (1H, DQF-COSY, TOCSY, ROESY, HSQC, HSQC-TOCSY and HMBC) in addition to chemical methods. Sugar and methylation analyses of native polysaccharides, absolute configuration assignment of constituent monosaccharides and NMR spectroscopy data revealed that these two P. parmentieri strains isolated in different countries possess the same structure of OPS with a very rare residue of 5,7-diamino-3,5,7,9-tetradeoxy-l-glycero-l-manno-non-2-ulosonic acid (pseudaminic acid) substituted in the position C-8: →3)-β-d-Galf-(1→3)-α-d-Galp-(1→8)-β-Pse4Ac5Ac7Ac-(2→6)-α-d-Glcp-(1→6)-β-d-Glcp-(1→. The previous study indicated that three other P. parmentieri strains, namely IFB5427, IFB5408 and IFB5443, exhibit a different OPS molecule than SCC3193 and IFB5432. The conducted biodiversity-oriented assays revealed that the P. parmentieri IFB5427 and IFB5408 strains possessing the same OPS structure yielded the highest genome-wide similarity, according to average nucleotide identity analyses, in addition to the greatest ability to macerate chicory tissue among the studied P. parmentieri strains. The current research demonstrated a novel OPS structure, characteristic of at least two P. parmentieri strains (SCC3193 and IFB5432), and discussed the observed heterogenicity in the OPS of P. parmentieri in a broad genomic and phenotype-related context.

Pectobacterium and Dickeya genus—A review on structural variations of O‐polysaccharides and their role in the pathogenic process of plants

“…These adhesion abilities, combined with the production of plant cell wall-degrading enzymes, T3SS, mobility and biofilm formation are important virulence factors of the pathogenic bacteria in plants (Mole et al, 2007). It was confirmed that OPSs of some Pectobacterium and Dickeya strains had an impact on the development of bacterial plant diseases (Bartnik et al, 2021(Bartnik et al, , 2022Duprey et al, 2019;Evans et al, 2010;Ossowska et al, 2022;Żołędowska et al, 2018; Figure 1). The OPSs also contribute to the resistance of phytopathogens to antimicrobial compounds (barrier function), which presumably promotes the ability to infect plants.…”

“…Recent structural studies of OPSs isolated from two other strains, namely P. parmentieri SCC3193 and IFB5432, indicate that these OPSs also have identical structures. Moreover, the mentioned OPSs have only a main chain, consisting of two residues of d-Gal, in pyranose and furanose form, two residues of d-Glc and a very rare residue of 5,7 -diamino-3,5,7,9-tetradeoxyl-glycerol-manno-non-2-ulosonic acid (Ossowska et al, 2022; Table 1). The latter component was reported previously in the repeating unit of the OPS isolated from Shigella boydii type 7.…”

“…is confirmed by numerous studies. It was found that P. parmentieri strains SCC3193, IFB5432, IFB5408, IFB5427 and D. dadantii 3937 caused the rotting of chicory leaves and potato tissues (Duprey et al, 2019;Ossowska et al, 2022;Żołędowska et al, 2018).…”

“…Nowadays, the serovar classification system tends to receive less attention, as evidenced by the limited number of known OPS structures (Czajkowski et al, 2015). So far, only nine OPSs isolated from Pectobacterium genus have been characterized (Czerwicka et al, 2011;Lukianova et al, 2020;Ossowska et al, 2016Ossowska et al, , 2022Senchenkova et al, 2003Senchenkova et al, , 2005Shneider et al, 2020; Table 1), and six chemical structures of the repetitive units of the OPSs have been determined for Dickeya spp. (Kowalczyk et al, 2020;Ossowska et al, 2017; Table 2).…”

“…Summary of the influence of O ‐polysaccharides of some Pectobacterium and Dickeya strains on the plant‐pathogenic process (Bartnik et al, 2021, 2022; Duprey et al, 2019; Evans et al, 2010; Ossowska et al, 2022; Żołędowska et al, 2018). …”