Physiological and Genetic Diversity in Rhizobium sullae from Morocco

Sulla is an important forage legume in the northern parts of Morocco and has a significant role in minimizing soil erosion. Sulla consists of two species Hedysarum coronarium L. and H. flexuosum L and both are well adapted to marginal areas where drought, salinity and alkalinity are the major problems. With the aim to characterize the bacterial symbiotic partner, Rhizobium sullae isolates from the nodules were sampled from sulla growing regions of Morocco. A total of 62 isolates were characterized so far, for various physiological characters such as resistance to salinity stress, water stress, high temperature stress, antibiotics, heavy metals, and various pH levels. The results revealed a considerable diversity for various physiological traits. The 62 isolates were divided into 14 clusters which showed a wide range of diversity both within and between the clusters. Genetic diversity of the isolates was analyzed by Amplified Ribosomal DNA Restriction Analysis (ARDRA) using two enzymes HinfI and HaeIII and data was used for cluster analysis. The results revealed that the individual genetic clusters contain isolates with diverse phenotypic traits, indicating no relationship between physiological and genetic groupings.