Inhibition of Rhizobium etli Polysaccharide Mutants by Phaseolus vulgaris Root Compounds

摘要: Crude bean root extracts of Phaseolus vulgaris were tested for inhibition the growth several polysaccharide mutants Rhizobium etli biovar phaseoli CE3. Mutants deficient only in exopolysaccharide and some O-antigen lipopolysaccharide no more sensitive than wild-type strain to extracts, whereas defective both much sensitive. The inhibitory activity was found at higher levels roots nodules stems or leaves. Inoculation with either polysaccharide-deficient R. did not appear affect level activity. Sequential extractions crude material petroleum ether, ethyl acetate, methanol, water partitioned into each solvent except methanol. major inhibitors ether acetate purified by C 18 high-performance liquid chromatography. These compounds all migrated very similarly thin-layer chromatography but distinguished their mass spectra. Absorbance spectra fluorescence properties suggested that they coumestans, one which had spectrum nuclear magnetic resonances coumestrol. results are discussed regard hypothesis role rhizobial polysaccharides is protect against plant toxins encountered during nodule development. Images