RELATIONSHIPS BETWEEN RfflZOBIAL CULTURABILITY FROM LEGUME NODULES AND NITRITE REDUCTASE ACTIVITY

摘要

The data support the hypothesis of a link between 3NPA content, bacterial non-culturability and presence of nirK gene. The observation is consistent also with studies on the presence of nirK in soil populations which indicate as this gene would be mostly represented by rhizobia not prone to culturing (Falk et al 2010). Hedysarum coronarium (sulla) regularly yields culturable rhizobia from its nodules. The fact that only some strains of R. sullae harbor the gene, in view of the fact that sulla is a plant still found in both spontaneous and cropped conditions, could suggest that denitrifying phenotypes in symbionts could possibly represent a transition between ancestral wild legumes equipped with anti-herbivory chemicals and the more modern domesticated crop species having lost most of their original self-protecting physiological traits.