Open AccessGenomic diversity and organization of complex polysaccharide biosynthesis clusters in the genus Dickeya
Author(s) -
Manish Ranjan,
Devanshi Khokhani,
Sanjeeva Nayaka,
Suchi Srivastava,
Zachary P. Keyser,
Ashish Ranjan
Publication year - 2021
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0245727
Subject(s) - biology , virulence , microbiology and biotechnology , gene cluster , genetics , gene , horizontal gene transfer , pathogenicity island , bacterial capsule , phylogenetics
The pectinolytic genus Dickeya (formerly Erwinia chrysanthemi ) comprises numerous pathogenic species which cause diseases in various crops and ornamental plants across the globe. Their pathogenicity is governed by complex multi-factorial processes of adaptive virulence gene regulation. Extracellular polysaccharides and lipopolysaccharides present on bacterial envelope surface play a significant role in the virulence of phytopathogenic bacteria. However, very little is known about the genomic location, diversity, and organization of the polysaccharide and lipopolysaccharide biosynthetic gene clusters in Dickeya . In the present study, we report the diversity and structural organization of the group 4 capsule (G4C)/O-antigen capsule, putative O-antigen lipopolysaccharide, enterobacterial common antigen, and core lipopolysaccharide biosynthesis clusters from 54 Dickeya strains. The presence of these clusters suggests that Dickeya has both capsule and lipopolysaccharide carrying O-antigen to their external surface. These gene clusters are key regulatory components in the composition and structure of the outer surface of Dickeya . The O-antigen capsule/group 4 capsule (G4C) coding region shows a variation in gene content and organization. Based on nucleotide sequence homology in these Dickey a strains, two distinct groups, G4C group I and G4C group II, exist. However, comparatively less variation is observed in the putative O-antigen lipopolysaccharide cluster in Dickeya spp . except for in Dickeya zeae . Also, enterobacterial common antigen and core lipopolysaccharide biosynthesis clusters are present mostly as conserved genomic regions. The variation in the O-antigen capsule and putative O-antigen lipopolysaccharide coding region in relation to their phylogeny suggests a role of multiple horizontal gene transfer (HGT) events. These multiple HGT processes might have been manifested into the current heterogeneity of O-antigen capsules and O-antigen lipopolysaccharides in Dickeya strains during its evolution.