CLONING OF A RECA-LIKE GENE FROM THE DIAZOTROPH HERBASPIRILLUM-SEROPEDICAE STRAIN Z78

A recombinant plasmid, pBMR5, carrying a recA-like gene of Herbaspiril lum seropedicae, was isolated from a H. seropedicae genomic library by intergeneric complementation of Escherichia coli recA mutant strain H B101. Quantitative survival experiments showed that pBMR5 restored the ultraviolet radiation and methyl methanesulfonate resistances and rec ombinational proficiency of this strain. Hybridization studies showed that there is DNA sequence homology between the recA gene of E. coli K 12 and that of H. seropedicae. Restriction sites for EcoRI, HindIII, B amHI, and Bg/II were found in the DNA insert derived from H. seropedic ae in pBMR5. A Tn5 insertional mutant of pBMR5, called pBMR26.2, faile d to restore recombination proficiency and methyl methanesulfonate and ultraviolet resistance to recA mutants of E. coli.