Figure 1.

Genes required for the natural transformation machinery of D. radiodurans. The putative functions of these genes are listed in Table 1. Cells were transformed with 400 ng of genomic DNA harboring a mutation (Δ9 deletion) in the rpoB gene conferring resistance to rifampicin. The results are the average of at least five independent experiments. (a): The frequency of [Rif^R] transformants is as low as the spontaneous frequency of [Rif^R] mutants. Statistically significant differences of transformation frequencies of the mutants, compared to those observed in wild type strain, were calculated using the non-parametric Mann Whitney test: ***P < 0.001; ns if P > 0.5.