SUMMARY: λ;gt WES derivatives carrying the citG (fumarase) gene of Bacillus subtilis have been detected by complementation of an Escherichia coli fumarase mutation in lysogen-filled plaques. The gerA gene, mutations in which affect the germination response of spores to L-alanine, is also present on the two citG transducing phages described. The cloned regions in these two phages include EcoRI-generated fragments of 5.0 kb and 1.4 kb; the former fragment carries citG4 +.