Distribution of Medicago species and their microsymbionts in a saline region of Algeria

2006

Article référencé dans le Web of Science WOS:000238763400004

Merabet Chahinez, Bekki A., Benrabah N., Bey M. B. H., Bouchentouf L., Ameziane H., Rezki M. A., Domergue O., Cleyet Marel J. C., Avarre Jean-Christophe, Béna Gilles, Bailly Xavier, Lajudie Philippe de

Arid Land Research and Management, 2006, 20 (3), p. 219-231 ISSN 1532-4982

We studied symbiosis of Medicago ciliaris and Medicago polymorpha, two legumes of forage and ecological importance in Algeria, especially in saline soil regions. We report the spatial distribution of the two species and their microsymbionts along salinity gradient transects in the Sebkha of Misserghin (Algeria, North Africa). Seeds and root nodules were sampled from 10 sites. Twenty-seven rhizobial strains were isolated from root nodules and characterized as fast-growers and slime-producers on yeast mannitol agar. By partial sequencing of the gene coding for the 16 S ribosomal RNA, they were found to be affiliated to Rhizobium, Sinorhizobium, and Agrobacterium but several strains had sequences with separate positions. Interestingly one of these was further assigned to Phyllobacterium. Opposite to rhizobia, the distribution of the two Medicago species varied along the salinity gradient, M. ciliaris being dominant in the low NaCl concentration zones and M. polymorpha dominant in the most saline zones. Tolerance to salinity, of both bacterial and plant partners, was studied under laboratory conditions, showing that plants are susceptible to NaCl concentrations of 50mM, 15-fold lower than that of their associated rhizobia (800mM).

Biotechnologies [084]

ALGERIE

Fonds IRD [F B010072624]

fdi:010072624