Symbiotic effects of deltamatB Rhizobium leguminosarum bv. trifolii mutant on clovers.
The role of malonate in symbiotic nitrogen metabolism has long been controversial, although it is known to occur in legume roots, especially in the nodules. Here we report that malonate metabolism plays a key role in the differentiation of bacteroids Rhizobium leguminosarum bv. trifolii in clover nodules. An operon, mat, that consists of three consecutive genes (matABC) has been discovered. Mat encodes enzymes that catalyze the uptake and conversion of malonate to acetyl-CoA through malonyl-CoA. A mutant bacteria, which replaced matB that encodes malonyl-CoA synthetase with a kanamycin resistant gene, was generated and infected with white clover. Clover growth was considerably reduced, even though nodules were formed. However, the nodules were filled with vacuoles, but not with bacteroids. This indicates that malonate metabolism is an important requirement for the formation of mature nodules that are filled with bacteroids.
An
Jae Hyung
JH
Department of Biochemistry, College of Science, Protein Network Research Center, Yonsei University, Seoul, Korea.
Lee
Hwan Young
HY
Ko
Kyoung Nam
KN
Kim
Eun-Soo
ES
Kim
Yu Sam
YS
D001426:Bacterial Proteins; D003066:Coenzyme A Ligases / Q000235:genetics / Q000378:metabolism; D029902:Medicago / Q000502:physiology*; D008854:Microscopy, Electron; D009154:Mutation; D018517:Plant Roots / Q000648:ultrastructure; D016961:Rhizobium leguminosarum / Q000235:genetics* / Q000502:physiology*; D013559:Symbiosis / Q000502:physiology
D001426:Bacterial Proteins; D003066:Coenzyme A Ligases; C021533:malonyl-CoA synthetase