Rhizobium extracellular structures in the symbiosis

Abstract

The extracellular and surface polysaccharides produced by Rhizobium species constitute a composite macromolecular interface between the bacterial cell and its environment. Several of these polysaccharides are involved in the complex series of interactions leading to the establishment of an effective Rhizobium-legume symbiosis. Extracellular heteropolysaccharides (EPSs) are found in culture supernatants, while capsular polysaccharides adhere to the cell surface. Cyclic (1-2)-β-d glucan is a periplasmic oligosaccharide that has also been found in the culture supernatants of some strains. The lipopolysaccharides (LPSs), which form part of the outer membrane and contain the O-somatic antigens, comprise the other major group of extracellular polysaccharides. In this review we will describe the major Rhizobium extracellular structures and their role in symbiosis with leguminous plants.

Promiscuity of Hosting Nitrogen Fixation in Rice: An Overview from the Legume Perspective

“…Rhizobia produce several groups of secreted polysaccharides that have been reviewed by Van Workum and Kijne (1998) and Coronado et al (1996). The main form of rhizobial exopolysaccharide (EPS) is a succinoiglycan called EPSI.…”

Structure and role in symbiosis of the exoB gene of Rhizobium leguminosarum bv trifolii

“…The extracellular and surface polysaccharides produced by Rhizobium constitute the interface between the bacterial cell and its environment and are involved in the interactions leading to the establishment of an eective Rhizobium-legume symbiosis (Coronado et al 1996). These polysaccharides include extracellular heteropolysaccharides (EPS), capsular polysaccharides, and lipopolysaccharides (LPS) of the outer membrane.…”

Avaliação de consórcios bacterianos para mitigar os efeitos do estresse hídrico em culturas de soja

“…Assim como as plantas, os microrganismos são capazes de sobreviver a estresse hídrico, usando mecanismos como: exopolissacarídeos, biofilme, produção de pigmentos e osmólitos intracelulares, entre outros (Chaves et al, 2002;Monier;Lindow, 2003). Os exopolissacarídeos, produzidos por microorganismos são compostos que se acumulam na superfície das células (Coronado et al, 1996), e tem sido associado como mecanismo de adaptação à condições estressantes ambientais em solos salinos, além de facilitar na tolerância das variações de temperaturas e estresse hídrico. Esses compostos degradam algumas substancias tóxicas, e facilitam a sobrevivência das plantas (Roper et al, 2007), além de proteger contra estresses ambientais (Coronado et al 1996).…”

“…Os exopolissacarídeos, produzidos por microorganismos são compostos que se acumulam na superfície das células (Coronado et al, 1996), e tem sido associado como mecanismo de adaptação à condições estressantes ambientais em solos salinos, além de facilitar na tolerância das variações de temperaturas e estresse hídrico. Esses compostos degradam algumas substancias tóxicas, e facilitam a sobrevivência das plantas (Roper et al, 2007), além de proteger contra estresses ambientais (Coronado et al 1996).…”