| nod factors of rhizobium are a key to the legume door. | symbiotic interactions between rhizobia and legumes are largely controlled by reciprocal signal exchange. legume roots excrete flavonoids which induce rhizobial nodulation genes to synthesize and excrete lipo-oligosaccharide nod factors. in turn, nod factors provoke deformation of the root hairs and nodule primordium formation. normally, rhizobia enter roots through infection threads in markedly curled root hairs. if nod factors are responsible for symbiosis-specific root hair deformation, they ... | 1994 | 7984092 |
| sulphation of rhizobium sp. ngr234 nod factors is dependent on noee, a new host-specificity gene. | rhizobia secrete specific lipo-chitooligosaccharide signals (lcos) called nod factors that are required for infection and nodulation of legumes. in rhizobium sp. ngr234, the reducing n-acetyl-d-glucosamine of lcos is substituted at c6 with 2-o-methyl-l-fucose which can be acetylated or sulphated. we identified a flavonoid-inducible locus on the symbiotic plasmid pngr234a that contains a new nodulation gene, noee, which is required for the sulphation of ngr234 nod factors (nodngr). noee was ident ... | 1997 | 9218762 |
| nolo and noei (hsniii) of rhizobium sp. ngr234 are involved in 3-o-carbamoylation and 2-o-methylation of nod factors. | loci unique to specific rhizobia direct the adjunction of special groups to the core lipo-oligosaccharide nod factors. host-specificity of nodulation (hsn) genes are thus essential for interaction with certain legumes. rhizobium sp. ngr234, which can nodulate >110 genera of legumes, possesses three hsn loci and secretes a large family of nod factors carrying specific substituents. among them are 3-o (or 4-o)- and 6-o-carbamoyl groups, an n-methyl group, and a 2-o-methylfucose residue which may b ... | 1998 | 9575146 |
| noll of rhizobium sp. strain ngr234 is required for o-acetyltransferase activity. | following (iso)flavonoid induction, nodulation genes of the symbiotic nitrogen-fixing bacterium rhizobium sp. strain ngr234 elaborate a large family of lipooligosaccharidic nod factors (nodngr factors). when secreted into the rhizosphere of compatible legumes, these signal molecules initiate root hair deformation and nodule development. the nonreducing glucosamine residue of nodngr factors are n acylated, n methylated, and mono- or biscarbamoylated, while position c-6 of the reducing extremity i ... | 1999 | 9922261 |
| effect of interactions on the nutrient status of a tropical soil treated with green manures and inorganic phosphate fertilizers. | integrated nutrient management systems using plant residues and inorganic p fertilizers have high potential for increasing crop production and ensuring sustainability in the tropics, but their adoption requires in-depth understanding of nutrient dynamics in such systems. this was examined in a highly weathered tropical soil treated with green manures (gms) and p fertilizers in two experiments conducted in the laboratory and glasshouse. the treatments were factorial combinations of the gms (calop ... | 2004 | 15252691 |