Morphologically Different Pectobacterium brasiliense Bacteriophages PP99 and PP101: Deacetylation of O-Polysaccharide by the Tail Spike Protein of Phage PP99 Accompanies the Infection.

Anna A Lukianova,Anna M Shpirt,Kirill K Miroshnikov,Mikhail M Shneider,Konstantin A Miroshnikov,Alexander S Shashkov,Peter V Evseev,Sofiya N Senchenkova,Ekaterina A Obraztsova,Anastasia P Kabanova,Yuriy A Knirel,Eugenia N Bugaeva,Stepan V Toschakov,Alexander N Ignatov

doi:10.3389/fmicb.2019.03147

Abstract

Soft rot caused by numerous species of Pectobacterium and Dickeya is a serious threat to the world production of potatoes. The application of bacteriophages to combat bacterial infections in medicine, agriculture, and the food industry requires the selection of comprehensively studied lytic phages and the knowledge of their infection mechanism for more rational composition of therapeutic cocktails. We present the study of two bacteriophages, infective for the Pectobacterium brasiliense strain F152. Podoviridae PP99 is a representative of the genus Zindervirus, and Myoviridae PP101 belongs to the still unclassified genomic group. The structure of O-polysaccharide of F152 was established by sugar analysis and 1D and 2D NMR spectroscopy:→ 4)-α-D-Manp6Ac-(1→ 2)-α-D-Manp-(1→ 3)-β-D-Galp-(1→ 3↑1α-l-6dTalpAc0−2The recombinant tail spike protein of phage PP99, gp55, was shown to deacetylate the side chain talose residue of bacterial O-polysaccharide, thus providing the selective attachment of the phage to the cell surface. Both phages demonstrate lytic behavior, thus being prospective for therapeutic purposes.

Highlights

Pectobacterium brasiliense (Pbr) is a member of the soft rot Pectobacteriaceae (SRP) (Adeolu et al, 2016)
Strain F152 induces a hypersensitive reaction in tobacco leaves and causes severe black leg symptoms on green plants and soft rot symptoms on potato tuber disks compared to the characterized strains of P. polaris, P. aquaticum, P. versatile, and P. atrosepticum in a temperature range from 20 to 28◦C
Measurements of Average nucleotide identity (ANI) and Digital DNA-DNA hybridization (dDDH) demonstrate a genetic difference between two clades of Pbr (Figure 1, Figure S1)

Summary

Introduction

Pectobacterium brasiliense (Pbr) is a member of the soft rot Pectobacteriaceae (SRP) (Adeolu et al, 2016). Pbr was first identified as a strain group within Pectobacterium carotovorum, causing severe black leg disease of potatoes in Brazil (Duarte et al, 2004). This group of strains shared some physiological properties with P. atrosepticum (Pat), and was able to grow in a broader range of environmental temperatures. Similar strains were identified as causative agents of black leg and soft rot of potatoes in many countries, including Russia (Malko et al, 2019; Voronina et al, 2019b). Following the taxonomic reassessment of phytopathogenic pectobacteria, Pbr was rated as a subspecies of the P. carotovorum (Nabhan et al, 2012), and was recently elevated to the species rank (Portier et al, 2019)

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Results

Conclusion