ISSN:
1573-5036
Keywords:
14C-naringenin assimilation
;
Nod factor synthesis
;
Rhizobium nod gene-inducer
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract The fate of 14C-naringenin during its specific activation of nod genes in Rhizobium leguminosarum bv. viciae was examined. After incubation with either strain RBL5560 or its pSym-cured derivative in a medium supplemented with 14C-naringenin at nod gene-inducing concentrations of 2 nM (ca. 12.5 kBq) plus cold acetate (0.5 μM), a radiocarbon inventory for the cells and supernatant extracts was obtained. The level of 14C-label incorporation was also determined in the fractionated cellular components. Using 14C-acetate at 0.5 μM (1036 kBq) and cold naringenin (2 nM) in incubations with strain RBL5560 as a separate treatment, the Nod metabolites were detected by thin layer and high performance liquid chromatographic methods and the data provided the basis for identification of the Nod factors from the supernatant obtained from 14C-naringenin treatments. Subsequent radio-biochemical and chemical analyses revealed that RBL5560 cells assimilated 14C-naringenin during the activation of nod genes. Our analysis also showed that labelled carbon atoms from the 14C-naringenin were incorporated into the acyl moiety of a lipo-oligosaccharide Nod factor, NodRlv IV, present in the culture supernatants of RBL5560. The pSym-cured derivative failed to synthesize any Nod metabolites in a 14C-naringenin supplemented medium. The tracing of flavonoid-derived carbon atoms to the acyl chain of a host-specific Nod factor, a moiety that defines host specificity for this Rhizobium, adds a new dimension to the signalling function of flavonoids in legume-Rhizobium interactions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00035056
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