Analysis of Xenorhabdus nematophila metabolic mutants yields insight into stages of Steinernema carpocapsae nematode intestinal colonization

Eric C. Martens, Frances M. Russell, Heidi Goodrich-Blair

Research output: Contribution to journalArticle

36 Scopus citations

Abstract

Xenorhabdus nematophila colonizes the intestinal tract of infective-juvenile (IJ) stage Steinernema carpocapsae nematodes. During colonization, X. nematophila multiplies within the lumen of a discrete region of the IJ intestine termed the vesicle. To begin to understand bacterial nutritional requirements during multiplication in the IJ vesicle, we analysed the colonization behaviour of several X. nematophila metabolic mutants, including amino acid and vitamin auxotrophs. X. nematophila mutants defective for para-aminobenzoate, pyridoxine or L-threonine biosynthesis exhibit substantially decreased colonization of IJs (0.1-50% of wild-type colonization). Analysis of gfp-labelled variants revealed that those mutant cells that can colonize the IJ vesicle differ noticeably from wild-type X. nematophila. One aberrant colonization phenotype exhibited by the metabolic mutants tested, but not wild-type X. nematophila, is a spherical shape indicative of apparently non-viable X. nematophila cells within the vesicle. Because these spherical cells appear to have initiated colonization but failed to proliferate, we term this type of colonization 'abortive'. In a portion of IJs grown on para-aminobenzoate auxotrophs, X. nematophila does not exhibit abortive colonization but rather reduced growth and filamentous cell morphology. Several mutants with defects in other amino acid, vitamin and nutrient metabolism pathways colonize IJs to wild-type levels suggesting that the IJ vesicle is replete with respect to a number of nutrients.

Original languageEnglish (US)
Pages (from-to)28-45
Number of pages18
JournalMolecular Microbiology
Volume58
Issue number1
DOIs
StatePublished - Oct 1 2005
Externally publishedYes

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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