Transfer of the Symbiotic Plasmid of Rhizobium etli CFN42 Requires Cointegration with p42a, Which May Be Mediated by Site-Specific Recombination

• DOI: 10.1128/jb.186.22.7538-7548.2004
• Publication Date: 2004-10-31T07:42:41Z
• Authors: Susana Brom; Lourdes Girard; Cristina Tun-Garrido; Alejandro García...; Patricia Bustos; Víctor González; David Romero
• Keywords: Phaseolus; Recombination, Genetic; 0301 basic medicine; Base Sequence; Gene Transfer, Horizontal; Integrases; Molecular Sequence Data; Gene Expression Regulation, Bacterial; Sequence Analysis, DNA; Rhizobium etli; 03 medical and health sciences; Conjugation, Genetic; Attachment Sites, Microbiological; Amino Acid Sequence; Symbiosis; Plasmids

ABSTRACT Plasmid p42a from Rhizobium etli CFN42 is self-transmissible and indispensable for conjugative transfer of the symbiotic plasmid (pSym). Most pSym transconjugants also inherit p42a. that lack always contain recombinant pSyms, which we designated RpSyms*. RpSyms* do not some segments instead have sequences, including replication regions. These novel plasmids are compatible with wild-type pSym, incompatible p42a, self-transmissible. The features derivatives simultaneously containing a an RpSym* were analyzed. Structural analysis 10 showed 7 shared one two pSym-p42a junctions. Sequencing this common junction revealed 53-bp region was 90% identical in 5-bp central flanked by 9- to 11-bp inverted repeats reminiscent bacterial phage attachment sites. A gene encoding integrase-like protein ( intA ) localized downstream site on Mutation or absence abolished recA mutant donor. Complementation restored pSym. We propose cointegration required transfer; may be achieved either through homologous recombination among large reiterated sequences IntA-mediated site-specific between Cointegrates formed system but resolved RecA-dependent vice versa generate feature these implies there unique regulation affects distribution nature due role cointegrate transfer.