Sigma 54-dependent transcriptional activators such as Escherichia coli NtrC, Rhizobium meliloti NifA, and Rhizobium leguminosarum DctD share similar central and carboxy-terminal domains but differ in the structure and function of their amino-terminal domains. We have deleted the amino-terminal and carboxy-terminal domains of R. leguminosarum DctD and have demonstrated that the central domain of...

The lipopolysaccharide structure of the nitrogen-fixing bacterium Rhizobium leguminosarum differs from that of Escherichia coli in several ways, one of which is the sugar composition of the core. The E. coli inner core consists of 3-deoxy-D-manno-octulosonic acid (Kdo) and L-glycero-D-manno-heptose (heptose), while the inner core of R. leguminosarum contains 2-keto-3-deoxy-D-manno-octulosonic a...

Rhizobium leguminosarum synthesizes polyhydroxybutyrate and glycogen as its main carbon storage compounds. To examine the role of these compounds in bacteroid development and in symbiotic efficiency, single and double mutants of R. leguminosarum bv. viciae were made which lack polyhydroxybutyrate synthase (phaC), glycogen synthase (glgA), or both. For comparison, a single phaC mutant also was i...

Fungicides seed dressing provides benefits by preventing fungal infection, conversely, damage the non-target organisms including plant and its symbiotic bacteria. In this study, the effect of two fungicides, carbendazim and thiophanate methyl, was assessed on the growth of pea and its symbiotic bacteria, Rhizobium leguminosarum. In vitro studies revealed that recommended concentration of fungic...

A mildly acid-sensitive mutant of Rhizobium leguminosarum bv. viciae WSM710 (WR6-35) produced colonies which were more mucoid in phenotype than the wild-type. Strain WR6-35 contained a single copy of Tn5 and the observed mucoid phenotype, acid sensitivity and Tn5-induced kanamycin resistance were 100% co-transducible using phage RL38. WR6-35 produced threefold more exopolysaccharide (EPS) than ...

Fifty four bacterial strains were isolated from root nodules of the grain legumes Cicer arietinum, Lens esculentus, Phaseolus vulgaris, Pisum sativum, and Vicia faba grown in cultivated lands of Beni-Suef Governorate (Egypt). Repetitive extragenic palindromic (REP)-polymerase chain reaction (PCR) clustered the strains into 15 REP-PCR groups. The nearly complete sequence of the 16S rRNA gene fro...

Transgenic alfalfa (Medicago sativa L. cv Regen) roots carrying genes encoding soybean lectin or pea (Pisum sativum) seed lectin (PSL) were inoculated with Bradyrhizobium japonicum or Rhizobium leguminosarum bv viciae, respectively, and their responses were compared with those of comparably inoculated control plants. We found that nodule-like structures formed on alfalfa roots only when the rhi...

Hybridization experiments were carried out between high molecular weight, denatured, agar-embedded deoxyribonucleic acid (DNA) and homologous, nonembedded, sheared, denatured (14)C-labeled DNA from a strain of Agrobacterium tumefaciens and Rhizobium leguminosarum (the reference strains) in the presence of sheared, nonembedded, nonlabeled DNA (competing DNA) from the same or different nomen-spec...

A cysE gene encoding a serine acetyltransferase (SAT) potentially involved in the biosynthesis of cysteine was identified approximately 4 kb upstream of the previously described aapJQMP gene cluster that encodes an amino acid permease in Rhizobium leguminosarum strain 3841. The gene exhibits >40% identity to the family of SATs containing N-terminal extensions that have been described for other ...

BacA is an integral membrane protein, the mutation of which leads to increased resistance to the antimicrobial peptides bleomycin and Bac7(1-35) and a greater sensitivity to SDS and vancomycin in Rhizobium leguminosarum bv. viciae, R. leguminosarum bv. phaseoli, and Rhizobium etli. The growth of Rhizobium strains on dicarboxylates as a sole carbon source was impaired in bacA mutants but was ove...