AUTHOR=Springer Katharina , Sänger Philipp-Albert , Moritz Christian , Felsl Angela , Rattei Thomas , Fuchs Thilo M. 

TITLE=Insecticidal Toxicity of Yersinia frederiksenii Involves the Novel Enterotoxin YacT

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=8

YEAR=2018

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2018.00392

DOI=10.3389/fcimb.2018.00392

ISSN=2235-2988

ABSTRACT=<p>The genus <italic>Yersinia</italic> comprises 19 species of which three are known as human and animal pathogens. Some species display toxicity toward invertebrates using the so-called toxin complex (TC) and/or determinants that are not yet known. Recent studies showed a remarkable variability of insecticidal activities when representatives of different <italic>Yersinia</italic> species (spp.) were subcutaneously injected into the greater wax moth, <italic>Galleria mellonella</italic>. Here, we demonstrate that <italic>Y. intermedia</italic> and <italic>Y. frederiksenii</italic> are highly toxic to this insect. A member of <italic>Y. Enterocolitica</italic> phylogroup 1B killed <italic>G. mellonella</italic> larvae with injection doses of approximately 38 cells only, thus resembling the insecticidal activity of <italic>Photorhabdus luminescens</italic>. The pathogenicity <italic>Yersinia</italic> spp. displays toward the larvae was higher at 15°C than at 30°C and independent of the TC. However, upon subtraction of all genes of the low-pathogenic <italic>Y. enterocolitica</italic> strain W22703 from the genomes of <italic>Y. intermedia</italic> and <italic>Y. frederiksenii</italic>, we identified a set of genes that may be responsible for the toxicity of these two species. Indeed, a mutant of <italic>Y. frederiksenii</italic> lacking <italic>yacT</italic>, a gene that encodes a protein similar to the heat-stable cytotonic enterotoxin (Ast) of <italic>Aeromonas hydrophila</italic>, exhibited a reduced pathogenicity toward <italic>G. mellonella</italic> larvae and altered the morphology of hemocytes. The data suggests that the repertoire of virulence determinants present in environmental <italic>Yersinia</italic> species remains to be elucidated.</p>