Genome sequence of the entomopathogenic Serratia entomophila isolate 626 and characterisation of the species specific itaconate degradation pathway

• Published in: BMC genomics Vol. 23; no. 1; pp. 1 - 22
• Main Authors: Vaughan, Amy L., Altermann, Eric, Glare, Travis R., Hurst, Mark R. H.
• Format: Journal Article
• Language: English
• Published: London BioMed Central Ltd 27.10.2022; BioMed Central; BMC
• Subjects: Analysis; Bacteria; Bacteria, Pathogenic; Bioassays; Biodegradation; Biopesticides; Carboxylic acids; Chromosome; Chromosomes; Chronic illnesses; Comparative analysis; Degradation; Entomopathogen; Gain-Loss; Gene order; Gene transfer; Genes; Genetic analysis; Genetic aspects; Genome; Genomes; Genomic analysis; Genomic islands; Genomics; Horizontal gene transfer; Horizontal transfer; Islands; Itaconate; Larvae; Mutants; Mutation; Nocardia corallina; Nucleotide sequence; Pasture; Pathogenicity; Pathogens; Phages; Physiological aspects; Plasmids; Proteins; Serratia; Virulence; Virulence (Microbiology); Virulence factors; United Kingdom; New Zealand
• ISSN: 1471-2164; 1471-2164
• DOI: 10.1186/s12864-022-08938-2

Isolates of Serratia entomophila and S. proteamaculans (Yersiniaceae) cause disease specific to the endemic New Zealand pasture pest, Costelytra giveni (Coleoptera: Scarabaeidae). Previous genomic profiling has shown that S. entomophila isolates appear to have conserved genomes and, where present, conserved plasmids. In the absence of C. giveni larvae, S. entomophila prevalence reduces in the soil over time, suggesting that S. entomophila has formed a host-specific relationship with C. giveni. To help define potential genetic mechanisms driving retention of the chronic disease of S. entomophila, the genome of the isolate 626 was sequenced, enabling the identification of unique chromosomal properties, and defining the gain/loss of accessory virulence factors relevant to pathogenicity to C. giveni larvae. We report the complete sequence of S. entomophila isolate 626, a causal agent of amber disease in C. giveni larvae. The genome of S. entomophila 626 is 5,046,461 bp, with 59.1% G + C content and encoding 4,695 predicted CDS. Comparative analysis with five previously sequenced Serratia species, S. proteamaculans 336X, S. marcescens Db11, S. nematodiphila DH-S01, S. grimesii BXF1, and S. ficaria NBRC 102596, revealed a core of 1,165 genes shared. Further comparisons between S. entomophila 626 and S. proteamaculans 336X revealed fewer predicted phage-like regions and genomic islands in 626, suggesting less horizontally acquired genetic material. Evidence is presented where, relative to S. proteamaculans 336X, S. entomophila 626 encodes fewer genomic islands and phages, alluding to limited horizontal gene transfer in S. entomophila.