Biomaterial Database

The Rhizobium meliloti region located downstream of the nod box n6 is involved in the specific nodulation of Medicago lupulina. 1995

C Plazanet, and G Réfrégier, and N Demont, and G Truchet, and C Rosenberg

Laboratoire de Biologie Moléculaire des Relations Plantes-Microorganismes, CNRS-INRA, Castanet-Tolosan, France.

Six nod box regulatory sequences are present in the Rhizobium meliloti genome. We have analysed the DNA region located downstream of nod box n6, and identified three open reading frames, designated nolQa, nolQb and nolS. LacZ fusions in these ORFs are not induced by classical nod gene inducers, which indicates that their expression either is not under the control of the nod box, or involves another regulatory mechanism acting in conjunction with the NodD/nod box regulatory circuit. Mutations in this n6 locus result in a delay in nodule formation on a particular host, Medicago lupulina. As this region is not strictly conserved among different R. meliloti strains, nolQa, nolQb and nolS may constitute auxiliary nodulation genes, for which the selection pressure is limited to particular host plants.

UI	MeSH Term	Description	Entries
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D005798	Genes, Bacterial	The functional hereditary units of BACTERIA.	Bacterial Gene,Bacterial Genes,Gene, Bacterial
D000455	Medicago sativa	A plant species of the family FABACEAE widely cultivated for ANIMAL FEED.	Alfalfa,Lucerne
D015964	Gene Expression Regulation, Bacterial	Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.	Bacterial Gene Expression Regulation,Regulation of Gene Expression, Bacterial,Regulation, Gene Expression, Bacterial
D016962	Sinorhizobium meliloti	A species of gram-negative, aerobic bacteria that causes formation of root nodules on some, but not all, types of sweet clover, MEDICAGO SATIVA, and fenugreek.	Ensifer meliloti,Rhizobium meliloti