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Title: Basis for the competitiveness of rhizobium japonicum in nodulation of soybean. Final progress report

Technical Report ·
OSTI ID:6579723

These studies were concerned with the determination of the characteristics of the soybean symbiont R. japonicum that are crucial to the inoculum competitiveness of one strain of the bacterium over other strains with respect to nodule formation. Our work has been focused on the initial infection events, such as attachment, which precede the development of a fully functional nodule because it is these primary events which determine the success or failure of a particular rhizobia to initiate infections. Experiments concerned with the attachment of R. japonicum to soybean roots have indicated that both soybean symbiotic and non-symbiotic species of rhizobia attach comparably well to soybean roots. There was no evidence of attachment mediated by soybean lectin, as previously claimed, but evidence was obtained for attachment mediated by pili on the Rhizobium cells. It was also found that the efficiency of infection varied substantially with culture age for certain strains while with other strains the efficiency of infection remained approximately constant during growth. We have utilized these observations to investigate the relationship between the efficiency of infection and competitiveness. An unexpected outcome of these studies was the finding that R. japonicum, and other slow-growing Rhizobium species, maintain both viability and symbiotic infectivity over prolonged periods of storage at ambient temperatures when suspended in water. The simplicity and cost-effectiveness of this storage procedure may provide an alternative method to the current practices employed in inoculum preparation. 2 figures, 3 tables.

Research Organization:
Battelle-Charles F. Kettering Research Lab., Yellow Springs, OH (USA)
DOE Contract Number:
AC02-81ER10895
OSTI ID:
6579723
Report Number(s):
DOE/ER/10895-1; ON: DE84016092
Country of Publication:
United States
Language:
English