The dnaJ (hsp40) locus in Rhizobium leguminosarum bv. phaseoli is requiredfor the establishment of an effective symbiosis with Phaseolus vulgaris

P121R25 is a Tn5-induced mutant of the effective Rhizobium legumirrosarum b y. phaseoli strain P121R that is unable to use glutamate as the sole carbon and nitrogen source and is defective in symbiotic nitrogen fixation, Enzym atic analysis showed that three enzymes implicated in glutamate metabolism (glutamate dehydrogenase, 2-oxoglutarate dehydrogenase, and glutamate synth ase) were affected by this mutation. Sequencing of the chromosomal locus bo rdering the Tn5 in P121R25 indicated the presence of the dnaK and dnaJ gene s in an arrangement similar to that described in R. leguminosarum by. vicia e (GenBank accession number Y14649), The mutation was located in the dnaJ ( hsp40) gene.