A link between arabinose utilization and oxalotrophy in Bradyrhizobium japonicum.
Rhizobia have a versatile catabolism that allows them to compete successfully with other microorganisms for nutrients in the soil and in the rhizosphere of their respective host plants. In this study, Bradyrhizobium japonicum USDA 110 was found to be able to utilize oxalate as the sole carbon source. A proteome analysis of cells grown in minimal medium containing arabinose suggested that oxalate oxidation extends the arabinose degradation branch via glycolaldehyde. A mutant of the key pathway genes oxc (for oxalyl-coenzyme A decarboxylase) and frc (for formyl-coenzyme A transferase) was constructed and shown to be (i) impaired in growth on arabinose and (ii) unable to grow on oxalate. Oxalate was detected in roots and, at elevated levels, in root nodules of four different B. japonicum host plants. Mixed-inoculation experiments with wild-type and oxc-frc mutant cells revealed that oxalotrophy might be a beneficial trait of B. japonicum at some stage during legume root nodule colonization.
Institute of Microbiology, ETH Zurich, Zurich, Switzerland.
Marion
M
Koch
Nathanaël
N
Delmotte
Christian H
CH
Ahrens
Ulrich
U
Omasits
Kathrin
K
Schneider
Francesco
F
Danza
Barnali
B
Padhi
Valérie
V
Murset
Olivier
O
Braissant
Julia A
JA
Vorholt
Hauke
H
Hennecke
Gabriella
G
Pessi
D001089:Arabinose / Q000378:metabolism*; D001426:Bacterial Proteins / Q000032:analysis; D020369:Bradyrhizobium / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D005798:Genes, Bacterial; D053858:Metabolic Networks and Pathways / Q000235:genetics; D009154:Mutation; D010070:Oxalates / Q000378:metabolism*; D018517:Plant Roots / Q000737:chemistry / Q000382:microbiology; D010944:Plants / Q000737:chemistry / Q000382:microbiology; D020543:Proteome / Q000032:analysis
D001426:Bacterial Proteins; D003470:Culture Media; D010070:Oxalates; D020543:Proteome; D002244:Carbon; D001089:Arabinose