Rhizobium fix genes mediate at least two communication steps in symbiotic nodule development

P. Putnoky, E. Grosskopf, D. T C Ha, G. Kiss, A. Kondorosi

Research output: Contribution to journalArticle

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Abstract

To identify bacterial genes involved in symbiotic nodule development, ineffective nodules of alfalfa (Medicago sativa) induced by 64 different Fix- mutants of Rhizobium meliloti were characterized by assaying for symbiotic gene expression and by morphological studies. The expression of leghemoglobin and nodulin-25 genes from alfalfa and of the nifHD genes from R. meliloti were monitored by hybridizing the appropriate DNA probes to RNA samples prepared from nodules. The mutants were accordingly divided into three groups. In group I none of the genes were expressed, in group II only the plant genes were expressed and in group III all three genes were transcribed. Light and electron microscopical analysis of nodules revealed that nodule development was halted at different stages in nodules induced by different group I mutants. In most cases nodules were empty lacking infection threads and bacteroids or nodules contained infection threads and a few released bacteroids. In nodules induced by a third mutant class bacteria were released into the host cells, however the formation of the peribacteroid membrane was not normal. On this basis we suggest that peribacteroid membrane formation precedes leghemoglobin and nodulin-25 induction, moreover, after induction of nodulation by the nod genes at least two communication steps between the bacteria and the host plants are necessary for the development of the mature nodule. By complementing each mutant of group I with a genomic R. meliloti library made in pLAFR1, four new fix loci were identified, indicating that several bacterial genes are involved in late nodule development.

Original languageEnglish
Pages (from-to)597-607
Number of pages11
JournalJournal of Cell Biology
Volume106
Issue number3
Publication statusPublished - 1988

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Rhizobium
Sinorhizobium meliloti
Medicago sativa
Leghemoglobin
Bacterial Genes
Genes
Bacteria
Plant Genes
Plant Development
Membranes
DNA Probes
Infection
Libraries
RNA
Electrons
Gene Expression
Light

ASJC Scopus subject areas

  • Cell Biology

Cite this

Putnoky, P., Grosskopf, E., Ha, D. T. C., Kiss, G., & Kondorosi, A. (1988). Rhizobium fix genes mediate at least two communication steps in symbiotic nodule development. Journal of Cell Biology, 106(3), 597-607.

Rhizobium fix genes mediate at least two communication steps in symbiotic nodule development. / Putnoky, P.; Grosskopf, E.; Ha, D. T C; Kiss, G.; Kondorosi, A.

In: Journal of Cell Biology, Vol. 106, No. 3, 1988, p. 597-607.

Research output: Contribution to journalArticle

Putnoky, P, Grosskopf, E, Ha, DTC, Kiss, G & Kondorosi, A 1988, 'Rhizobium fix genes mediate at least two communication steps in symbiotic nodule development', Journal of Cell Biology, vol. 106, no. 3, pp. 597-607.
Putnoky, P. ; Grosskopf, E. ; Ha, D. T C ; Kiss, G. ; Kondorosi, A. / Rhizobium fix genes mediate at least two communication steps in symbiotic nodule development. In: Journal of Cell Biology. 1988 ; Vol. 106, No. 3. pp. 597-607.
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