We studied the production of xyloglucanase enzymes of leguminous roots in the presence of Rhizobium and arbuscularmycorrhizal (AM) fungi. The AM fungus Glomus mosseae and Sinorhizobium meliloti GR4 for alfalfa, Rhizobium leguminosarum bv. viceae Rlv 13 for pea, R. leguminosarum bv. trifolii 2152 for clover, R. tropici CIAT 899 for bean and Mesorrhizobium mediterraneum USDA 3392 for chickpea. Th...

Melanin production by Rhizobium meliloti GR4 is linked to nonsymbiotic plasmid pRmeGR4b (140 MDa). Transfer of this plasmid to GR4-cured derivatives or to Agrobacterium tumefaciens enables these bacteria to produce melanin. Sequence analysis of a 3.5-kb PstI fragment of plasmid pRmeGR4b has revealed the presence of a open reading frame 1,481-bp that codes for a protein whose sequence shows stro...

The acidic exopolysaccharide (EPS) secreted in large amounts by the symbiotic nitrogen-fixing bacterium Rhizobium leguminosarum bv. trifolii is required for the establishment of an effective symbiosis with the host plant Trifolium spp. EPS biosynthesis in rhizobia is a very complex process regulated at both transcriptional and post-transcriptional levels and influenced by various nutritional an...

Plants engineer the rhizosphere to their advantage by secreting various nutrients and secondary metabolites. Coupling transcriptomic and metabolomic analyses of the pea (Pisum sativum) rhizosphere, a suite of bioreporters has been developed in Rhizobium leguminosarum bv viciae strain 3841, and these detect metabolites secreted by roots in space and time. Fourteen bacterial lux fusion bioreporte...

Biuret deamination is an essential step in cyanuric acid mineralization. In the well-studied atrazine degrading bacterium Pseudomonas sp. strain ADP, the amidase AtzE catalyzes this step. However, Rhizobium leguminosarum bv. viciae 3841 uses an unrelated cysteine hydrolase, BiuH, instead. Herein, structures of BiuH, BiuH with bound inhibitor and variants of BiuH are reported. The substrate is b...

Gas chromatographic and mass spectrometric analyses of derivatized culture medium extracts were used to identify the products of flavonoid metabolism by rhizobia. A number of Rhizobium species and biovars degraded their nod gene-inducing flavonoids by mechanisms which originated in a cleavage of the C-ring of the molecule and which yielded conserved A- and B-ring products among the metabolites....

The effects of foliar absorbed nutrients on root processes related to assimilation of nitrogen under presence or absence of molybdenum (Mo) were studied. Pea plants (Pisum sativum L.), var. Avola were grown until the 15th day in a glasshouse on liquid nutrient solution both without and with Mo added to the media. Plants were inoculated with bacterial suspension of Rhizobuium leguminosarum bv. V...