Effective symbiosis between Rhizobium etli and Phaseolus vulgaris requires the alarmone ppGpp.

ABSTRACT: The symbiotic interaction between Rhizobium etli and Phaseolus vulgaris, the common bean plant, ultimately results in the formation of nitrogen-fixing nodules. Many aspects of the intermediate and late stages of this interaction are still poorly understood. The R. etli relA gene was identified through a genome-wide screening for R. etli symbiotic mutants. RelA has a pivotal role in cellular physiology, as it catalyzes the synthesis of (p)ppGpp, which mediates the stringent response in bacteria. The synthesis of ppGpp was abolished in an R. etli relA mutant strain under conditions of amino acid starvation. Plants nodulated by an R. etli relA mutant had a strongly reduced nitrogen fixation activity (75% reduction). Also, at the microscopic level, bacteroid morphology was altered, with the si

SUBMITTER: Moris M 

PROVIDER: S-EPMC1196010 | biostudies-literature | 2005 Aug

REPOSITORIES: biostudies-literature