title: A vector for the site-directed, genomic integration of foreign DNA into soybean root-nodule bacteria.
abstract: A non-essential DNA region carrying two different repeated sequences (RSβ3 and RSα9) adjacent to a nitrogen fixation (nif) gene cluster has been identified previously in Bradyrhizobium japonicum strain 110. In closely related B. japonicum strains a similar genomic arrangement was found. We constructed a mobilizable plasmid vector carrying RSβ3 and RSα9, and a kanamycin resistance cassette (nptII gene) plus suitable cloning sites inserted between the two repeated sequences. Using this vector (pRJ1035), stable integration of a lacZ gene fusion into the B. japonicum genomic RS region was achieved. The resulting strain yielded more than 10-fold higher β-galactosidase activity in soybean root nodules as compared to a B. japonicum strain carrying the same lacZ fusion on a pRK290-based plasmid.
authors.affiliation: Mikrobiologisches Institut, Eidgenössische Technische Hochschule, ETH-Zentrum, Universitätstrasse 2, CH-8092, Zürich, Switzerland.
authors.forename: G
authors.initials: G
authors.lastname: Acuña
authors.forename: A
authors.initials: A
authors.lastname: Alvarez-Morales
authors.forename: M
authors.initials: M
authors.lastname: Hahn
authors.forename: H
authors.initials: H
authors.lastname: Hennecke