The Journal of General and Applied Microbiology
Online ISSN : 1349-8037
Print ISSN : 0022-1260
ISSN-L : 0022-1260
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Localization of the reb operon expression is inconsistent with that of the R-body production in the stem nodules formed by Azorhizobium caulinodans mutants having a deletion of praR
Jun-ichi MatsuokaFumiko IshizunaTetsuhiro OgawaMakoto HidakaLowela SiarotToshihiro Aono
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2019 Volume 65 Issue 4 Pages 209-213


Azorhizobium caulinodans, a kind of rhizobia, has a reb operon encoding pathogenic R-body components, whose expression is usually repressed by a transcription factor PraR. Mutation on praR induced a high expression of reb operon and the formation of aberrant nodules, in which both morphologically normal and shrunken host cells were observed. Histochemical GUS analyses of praR mutant expressing reb operon-uidA fusion revealed that the bacterial cells within the normal host cells highly expressed the reb operon, but rarely produced R-bodies. On the other hand, the bacterial cells within the shrunken host cells frequently produced R-bodies but rarely expressed the reb operon. This suggests that R-body production is not only regulated at the transcriptional level, but by other regulatory mechanisms as well.

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© 2019, Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
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