A Rhizobium meliloti lipopolysaccharide mutant altered in competitiveness for nodulation of alfalfa.

摘要: A transposon Tn5-induced mutant of Rhizobium meliloti Rm2011, designated Rm6963, showed a rough colony morphology on rich and minimal media an altered lipopolysaccharide (LPS). Major differences from the wild-type LPS were observed in (i) hexose 2-keto-3-deoxyoctonate elution profiles crude phenol extracts chromatographed Sepharose CL-4B, (ii) silver-stained sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis patterns purified fractions, (iii) immunoreactivities otherwise present parental strain Rm2011. In addition, Rm6963 lost ability to grow Luria-Bertani medium containing hydrophobic compounds deoxycholate or SDS decrease survival TY supplemented with high calcium concentrations. The also had symbiotic properties. formed nodules that fixed nitrogen but delayed even reduced nodulate primary root alfalfa without showing changes position nodule distribution along roots. Furthermore, 2 3 weeks after inoculation, plants nodulated by smaller than control inoculated bacteria correlation transient fixation. most experiments, recovered later expressing full nitrogen-fixing phenotype developing abnormally number small lateral roots 1 month. was deficient compete for nodulation. coinoculation experiments equal bacterial numbers both rhizobia, only parent uppermost nodules. ratio approximately 100 favoring necessary obtain (1:1) occupancy. These results show alterations which include lead during association affects timing emergence, progress fixation, competitiveness