Retama-rhizobia symbiosis studies in some countries of the Mediterranean Basin

Abstract

The bacteria called rhizobia are nitrogen-fixing bacteria which establish symbioses with plant species in the legume family. They induce positive interaction between soil microorganisms and the plant and are essential for plant growth in semiarid Mediterranean ecosystems that usually present severe water stress, scarcity of plants, low available nutrients and microbiological activity. Considered as one of the endemic legume shrubs of the Mediterranean basin, Retama plays an important role in nitrogen cycling, and thus, can be used to restore heavily disturbed and degraded soils. These species are adapted to harsh environmental conditions and their establishment and growth are enhanced by their ability to enter into effective symbiosis with multiple rhizobia species. In this article, we review the cumulative evidence of the Retama-rhizobia symbiosis in the Mediterranean basin and its ecological impact on revegetation and soil fertilization.