Virulence of Auxotrophic Mutants of Erwinia aroideae

Abstract

The virulence of a pathogen depends upon numerous factors, including the availability of essential nutrilites from the host. If the host cannot supply all these nutrilites, either in quantity or in a form suitable for assimilation, the pathogen cannot proliferate and produce the characteristic reactions in the host. For example, purine-requiring mutants of Salmonella typhosa ¹ and of Klebsiella pneumoniae ² were avirulent for mice because the requirement for purine was apparently not satisfied by the host. Garber et al. ² suggested that auxotrophic mutants of pathogens may be useful for purposes of bioassay. Preliminary data from experiments using a plant pathogen, Erwinia aroideae, and the potato tuber, var. Red Russet, suggest that this technique may be extended to plant material in certain instances.