Project Number: 1275-21000-226-02
Project Type: Reimbursable

Start Date: Jun 01, 2007
End Date: May 31, 2010

Objective:
Isolation of rhizobia from Egyptian soils that form symbioses with the 18 indigenous species of Medicago. Mapping of the nodulating rhizobial populations in Egyptian soils using an approach based on genomics known as Multi-locus Sequence Typing. Characterization of infectivity and subsequent efficiency of symbioses of isolates with a selected annual medic suitable as a cover and fallow crop in the arid Egyptian region located within the Toshka Project.

Approach:
Nodules will be collected from Medicago species growing in their natural habitat, mostly along the Egyptian coastline. The rhizobial occupant within each nodule will be recovered in culture using standard techniques. The genotype of each nodule occupant will be determined by preparing DNA from cultured cells, amplifying 10 chromosomal loci using specific PCR methods and subsequently determining the allele of each of the 10 loci by sequence analysis for each recovered genotype. Complex statistical analyses will be used to map the rhizobial populations. Rhizobia that were assigned to different genomes will be tested for infectivity and efficiency for nitrogen fixation using axenic plant cultures and a Medicago species suitable for production in the arid region of the Toshka Project.