Genetic and Phenotypic Characterization of a Cluster of Mutations in the spoVA locus of Bacillus subtilis

Microbiology Unit, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK ABSTRACT Twenty-nine mutants blocked during stage V of sporulation have been isolated following directed mutagenesis of the lys-1 region of the Bacillus subtilis 168 chromosome. All of a sample of eight mutants tested are unaffected in sporulation marker events up to stage IV but did not produce dipicolinic acid. They produced stable ‘phase white’ spores that were released from the mother cell, and were partially resistant to toluene and lysozyme but sensitive to chloroform and heat. Mutation spoVA89 , known to be in the lys-1 region, showed similar phenotypic characteristics. Three-factor transformation crosses and recombination indices showed that the new mutations and spoVA89 lie in a single linkage group, which maps between lys-1 and another sporulation locus, spoIIA. The size of the spoVA locus is such that it probably contains several genes, and these may be contiguous with the cluster of genes included within the spoIIA locus. Keywords: RI, recombination index