Cloning of rec A gene from Xanthomonas oryzae isolate 8707

Abstract

RecA-like gene of Xanthomonas oryzae isolate 8707 chromosomal DNA have been cloned by using rationale of complementation E. coli recA-mutation and selected for mitomycin C resistant phenotype. Four transformants from six thousand colonies were retransformed into E. coli DH5a, HB101 and BW368 and checked for MMS and mitomycin C resistant. Result from Southern blot analysis of one of these transformants named pSM-A1 confirmed that the insert portion of this clone derived from Xanthomonas oryzae isolate 8707 chromosomal DNA. Significantly, from immunological analysis antiserum raised against E. coli RecA protein cross-reacted with Xanthomonas phaseolin, Xanthomonas oryzae 8707, Xanthonmonas campestris pv campestris. Furthermore, it also cross-reacted with cell lysate from E. coli BW368 harboring pSM-A1 but it did not react with cell lysate from E. coli BW368 RecA protein, A single band detected from pSM A1 cell lysate with an apparent molecular weight nearly equal to a single band detected from Xanthomonas oryzae isolate 8707 cell lysate and a protein band molecular weight 40,000 E. coli protein, These results indicated that pSM-Al clone contains Xanthomonas oryzae isolate 8707 recA-like gene.