The ''Erwiniaceae'' are a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Gram-negative bacteria Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall ...

which includes a number of

plant pathogens Plant pathology (also phytopathology) is the scientific study of diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomyc ...

and insect endosymbionts. This family is a member of the order

Enterobacterales Enterobacterales is an order of Gram-negative, non-spore forming, facultatively anaerobic, rod-shaped bacteria with the class Gammaproteobacteria. The type genus of this order is ''Enterobacter.'' The name Enterobacterales is derived from the ...

in the class

Gammaproteobacteria Gammaproteobacteria is a class of bacteria in the phylum Pseudomonadota (synonym Proteobacteria). It contains about 250 genera, which makes it the most genera-rich taxon of the Prokaryotes. Several medically, ecologically, and scientifically imp ...

of the phylum

Pseudomonadota Pseudomonadota (synonym Proteobacteria) is a major phylum of Gram-negative bacteria. The renaming of phyla in 2021 remains controversial among microbiologists, many of whom continue to use the earlier names of long standing in the literature. The ...

. The type genus of this family is ''

Erwinia ''Erwinia'' is a genus of Enterobacterales bacteria containing mostly plant pathogenic species which was named for the famous plant pathologist, Erwin Frink Smith. It contains Gram-negative bacteria related to ''Escherichia coli'', ''Shigella'' ...

.'' The name ''Erwiniaceae'' is derived from the Latin term ''Erwinia'', referring the type genus of the family and the suffix "-aceae", an ending used to denote a family. Together, ''Erwiniaceae'' refers to a family whose nomenclatural type is the genus ''Erwinia''.

Biochemical characteristics and molecular signatures

These bacteria are catalase-positive, oxidase-negative, and do not produce indole or hydrogen disulfide. Most species are positive for Voges-Proskauer test, with the exception of ''Erwinia toletana, Erwinia ypographi'' and some strains of ''Erwinia oleae.'' 12

conserved signature indels Conserved signature inserts and deletions (CSIs) in protein sequences provide an important category of molecular markers for understanding phylogenetic relationships. CSIs, brought about by rare genetic changes, provide useful phylogenetic markers ...

(CSIs) were identified through genomic analyses as exclusive for this family in the proteins

glutamate–cysteine ligase Glutamate—cysteine ligase (GCL) ), previously known as γ-glutamylcysteine synthetase (GCS), is the first enzyme of the cellular glutathione (GSH) biosynthetic pathway that catalyzes the chemical reaction: L-glutamate + L-cysteine + ATP \rig ...

DNA gyrase DNA gyrase, or simply gyrase, is an enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrat ...

(subunit B), LPS assembly protein LptD, thiol:disulfide interchange protein DsbA precursor, two-component sensor

histidine kinase Histidine kinases (HK) are multifunctional, and in non-animal kingdoms, typically transmembrane, proteins of the transferase class of enzymes that play a role in signal transduction across the cellular membrane. The vast majority of HKs are hom ...

RNA helicase Helicases are a class of enzymes thought to be vital to all organisms. Their main function is to unpack an organism's genetic material. Helicases are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separati ...

, tRNA pseudouridine(13) synthase TruD, glycine/betaine ABC transporter ATP-binding protein,

superoxide dismutase Superoxide dismutase (SOD, ) is an enzyme that alternately catalyzes the dismutation (or partitioning) of the superoxide () radical into ordinary molecular oxygen (O2) and hydrogen peroxide (). Superoxide is produced as a by-product of oxygen me ...

, and stationary phase inducible protein CsiE. These CSIs provide a reliable molecular method of identification and differentiation of ''Erwiniaceae'' species from other families in the order ''Enterobacterales'' and other bacteria.

Historical systematics and current taxonomy

''Erwiniaceae'', as of 2021, contains eight validly published genera. Members of this family were originally members of the family ''

Enterobacteriaceae Enterobacteriaceae is a large family (biology), family of Gram-negative bacteria. It was first proposed by Rahn in 1936, and now includes over 30 genera and more than 100 species. Its classification above the level of family is still a subject ...

'', a large phylogenetically unrelated group of species with distinct biochemical characteristics and different ecological niches. The original assignment of species into the family ''Enterobacteriaceae'' was largely based on 16S rRNA genome sequence analyses, which is known to have low discriminatory power and the results of which changes depends on the algorithm and organism information used. Despite this, the analyses still exhibited polyphyletic branching, indicating the presence of distinct subgroups within the family. In 2016, Adeolu et al. proposed the division of ''Enterobacteriaceae'' into 7 novel families based on comparative genomic analyses and the branching pattern of various phylogenetic trees constructed from conserved genome sequences, 16S rRNA sequences and multilocus sequence analyses. Molecular markers, specifically

, specific to this family were also identified as evidence supporting the division independent of phylogenetic trees.

References

Gram-negative bacteria Enterobacterales Bacteria families {{gammaproteobacteria-stub