Bacteria of the genus @entity69249 are symbionts of soil entomopathogenic @entity2199 of the genus Steinernema. This symbiotic association constitutes an insecticidal complex active against a wide range of insect pests. Within @entity69250 species, the @entity69250 CS03 strain (Xb CS03) is nonvirulent when directly injected into lepidopteran insects, and displays a low virulence when associated with its Steinernema symbiont. The genome of Xb CS03 was sequenced and compared with the genome of a virulent strain, @entity69249 (Xb SS-2004). The genome size and content widely differed between the two strains. Indeed, Xb CS03 had a large genome containing several specific loci involved in the inhibition of competitors, including a few NRPS-PKS loci (nonribosomal peptide synthetases and polyketide synthases) producing antimicrobial molecules. Consistently, Xb CS03 had a greater antimicrobial activity than Xb SS-2004. The Xb CS03 strain contained more pseudogenes than Xb SS-2004. Decay of genes involved in the host invasion and exploitation (toxins, invasins, or extracellular enzymes) was particularly important in Xb CS03. This may provide an explanation for the nonvirulence of the strain when injected into an insect host. We suggest that Xb CS03 and Xb SS-2004 followed divergent evolutionary scenarios to cope with their peculiar life cycle. The fitness strategy of Xb CS03 would involve competitor inhibition, whereas Xb SS-2004 would quickly and efficiently kill the insect host. Hence, @entity69249 strains would have widely divergent host exploitation strategies, which impact their genome structure.

Comparative Genomics between Two XXXX Strains Highlights Differential Evolutionary Scenarios within an Entomopathogenic Bacterial Species.

@entity69249 :: ('406818', 'Species') :: ['Xenorhabdus', 'X. bovienii SS-2004'] @entity2199 :: ('6239', 'Species') :: ['nematodes'] @entity69250 :: ('40576', 'Species') :: ['X. bovienii', 'Xenorhabdus bovienii']
@entity69250 :: (40576,Species) :: ['Xenorhabdus bovienii']
