title: Extended Region of Nodulation Genes in Rhizobium meliloti 1021. I. Phenotypes of Tn5 Insertion Mutants.
abstract: Rhizobium meliloti Nod(-) mutant WL131, a derivative of wild-type strain 102F51, was complemented by a clone bank of wild-type R. meliloti 1021 DNA, and clone pRmJT5 was recovered. Transfer of pRmJT5 conferred alfalfa nodulation on other Rhizobium species, indicating a role in host range determination for pRmJT5. Mutagenesis of pRmJT5 revealed several segments in which transposon insertion causes delay in nodulation, and/or marked reduction of the number of nodules formed on host alfalfa plants. The set of mutants indicated five regions in which nod genes are located; one mutant, nod-216, is located in a region not previously reported to encode a nodulation gene. Other mutant phenotypes correlated with the positions of open reading frames for nodH, nodF and nodE , and with a 2.2-kb EcoRI fragment. A mutant in nodG had no altered phenotype in this strain. One nodulation mutant was shown to be a large deletion of the common nod gene region. We present a discussion comparing the various studies made on this extended nod gene region.
authors.affiliation: Department of Biological Sciences, Stanford University, Stanford, California 94305.
authors.forename: J A
authors.initials: JA
authors.lastname: Swanson
authors.forename: J K
authors.initials: JK
authors.lastname: Tu
authors.forename: J
authors.initials: J
authors.lastname: Ogawa
authors.forename: R
authors.initials: R
authors.lastname: Sanga
authors.forename: R F
authors.initials: RF
authors.lastname: Fisher
authors.forename: S R
authors.initials: SR
authors.lastname: Long