Cloning of <i>nod</i> gene regions from mesquite rhizobia and bradyrhizobia and nucleotide sequence of the <i>nodD</i> gene from mesquite rhizobia

TitleCloning of nod gene regions from mesquite rhizobia and bradyrhizobia and nucleotide sequence of the nodD gene from mesquite rhizobia
Publication TypeJournal Article
Year of Publication1995
AuthorsThomas PM, Golly KF, Virginia RA, Zyskind JW
JournalApplied and Environmental Microbiology
Volume61
Pagination3422-3429
Date Published1995
Call Number00646
Keywordsarticle, articles, bradyrhizobia, genetics,bradyrhizobia, genetics,rhizobia, journal, journals, Prosopis,bradyrhizobia, Prosopis,rhizobia, rhizobia, root,Prosopis rhizobia, soil,bradyrhizobia, soil,rhizobia
AbstractNitrogen-fixing symbiosis between acteria and the tree legume mesquite (Prosopis glandulosa) is important for the maintenance of many desert ecosystems. Genes essential for nodulation and for extending the host range to mesquite were isolated from cosmid libraries of Rhizobium (mesquite) sp. strain HW17b and Bradyrhizobium (mesquite) sp. strain HW10h and were shown to be closely linked. All of the cosmid clones of rhizobia that extneded the host range of Rhizobium (Parasponia) sp. strain NGR234CS to mesquite also supported nodulatoin of a Sym- mesquite strain. The cosmid clones of bradyrhizobia that extended the host range of Rhizobium (Parasponia) sp. strain NGR234CS to mesquite were only able to confer nodulation ability in the Sym- mesquite strain if they also contained a nodD-hybridizing region. Subclones containing just the nodD genes of either genus did not extend the host range of Rhizobium (Parasponia) sp. to mesquite, indicating that the nodD gene is insufficient for mesquite nodulation. The nodD gene region is conserved among mesquite-nodulating rhizobia regardless of the soil depth from which they were collected, indicating descent from a common ancestor. In a tree of distance relationships. the NodD amino acid sequence from mesquite rhizobia clusters with homologs from symbionts that can infect both herbaceous and tree legumes, including Rhizobium tropici, Rhizobium leguminosarum bv. phaseoli, Rhizobium loti, and Bradyrhizobium japonicum.