1993 Fiscal Year Final Research Report Summary
Genetic analysis of Bradyrhizobium japonicum isolates possessing highly reiteratied DNA sequences
| Project/Area Number |
04660066
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
土壌・肥料
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| Research Institution | IBARKI UNIVERSITY |
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Principal Investigator |
MINAMISAWA Kiwamu IBARKI UNIVERSITY SCHOOL OF AGRICULTURE ASSOCIATE PROFESSOR, 農学部, 助教授 (70167667)
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| Project Period (FY) |
1992 – 1993
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| Keywords | soybean / Bradyrhizobium japonicum / repeated sequence / insertion element / highly reiterated DNA sequence |
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| Research Abstract |
During DNA fingerprinting of indigenous Bradyrhizobium japonicum by repeated sequence (RSalpha and RSbeta), we found many isolates possessing highly reiterated RSs (HRS isolates) from two fields in Japan. Some HRS isolates harbors approximately 200 copies of RSalpha on their genomes. Analysis of pulse field gel electrophoresis indicates that RSalpha copies are distributed to 74% region on HRS isolate genomes and to 17% region on normal isolate genomes. With respect to symbiotic features of HRS isolates, nodulation, nitrogenase activity and hydrogenase activity of HRS isolates were similar to that of normal isolates. However, HRS and normal isolates differed in growth rates in YM medium. Generation time of HRS isolates showed 5-9 h, While normal isolates showed 4-6 h of genaration time. These results strongly suggest that RSs transposition and genomic rearrangement occur on the genomes of B.japonicum HRS isolates.
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