Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Formation of novel polysaccharides by Bradyrhizobium japonicum bacteroids in soybean nodules

Journal Article · · Applied and Environmental Microbiology; (United States)
OSTI ID:5488037
; ;  [1];  [2]
  1. Ohio State Univ., Wooster (United States)
  2. Univ. of Georgia, Athens (United States)

Certain strains of Bradyrhizobium japonicum form a previously unknown polysaccharide in the root nodules of soybean plants (Glycine max (L.) Merr.). The polysaccharide accumulates inside of the symbiosome membrane-the plant-derived membrane enclosing the bacteroids. In older nodules (60 days after planting), the polysaccharide occupies most of the symbiosome volume and symbiosomes become enlarged so that there is little host cytoplasm in infected cells. The two different groups of B. japonicum which produce different types of polysaccharide in culture produce polysaccharides of similar composition in nodules. Polysaccharide formed by group I strains (e.g., USDA 5 and USDA 123) is composed of rhamnose, galactose, and 2-O-methylglucuronic acid, while polysaccharide formed by group II strains (e.g., USDA 31 and USDA 39) is composed of rhamnose and 4-O-methylglucuronic acid. That the polysaccharide is a bacterial product is indicated by its composition plus the fact that polysaccharide formation is independent of host genotype but is dependent on the bacterial genotype. Polysaccharide formation in nodules is common among strains in serogroups 123, 127, 129, and 31, with 27 of 39 strains (69%) testing positive. Polysaccharide formation in nodules is uncommon among other B. japonicum serogroups, with only 1 strain in 18 (6%) testing positive.

DOE Contract Number:
FG09-87ER13810
OSTI ID:
5488037
Journal Information:
Applied and Environmental Microbiology; (United States), Journal Name: Applied and Environmental Microbiology; (United States) Vol. 58:2; ISSN 0099-2240; ISSN AEMID
Country of Publication:
United States
Language:
English