Salt tolerance in<i>Rhizobium</i>: A possible role for betaines

Abstract

Rhizobium cells have evolved a variety of adaptative mechanisms to salt stress, such as accumulation of inorganic and organic solutes. A better understanding of the biochemical basis of osmoregulation in Rhizobium is of cardinal importance since the deleterious effect of salt stress on the survival and multiplication of these bacteria is well established. Current knowledge is briefly reviewed and experimental evidence on the beneficial effect of betaines on several Rhizobium strains is summarized. This information may help to shed light on similar adaptations in legumes of agricultural and economic importance.