Journal ArticleDOI
Rhizobium meliloti purine auxotrophs arenod + but defective in nitrogen fixation
S. K. Swamynathan,Aqbal Singh +1 more
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TLDR
External supplementation of the plant growth substrate with purines or their biosynthetic intermediates fails to restore symbiosis, and the failure of complementation of these auxotrophs with the known symbiotic genes demonstrates that these mutants perhaps define a new set of genes influencing the symbiotic process in Rhizobium meliloti.Abstract:
Several purine auxotrophs were isolated inRhizobium meliloti and characterized for their nutritional requirements. They were found to produce small, irregular nodules lacking any detectable nitrogenase activity onMedicago sativa. The symbiotic aberration manifests itself only in the late developmental stage, for, (i) these purine auxotrophs infect theMedicago sativa root hairs by forming normal infection threads, and (ii) the mutants are recovered from the root nodules induced by them. External supplementation of the plant growth substrate with purines or their biosynthetic intermediates fails to restore symbiosis. This, and the failure of complementation of these auxotrophs with the known symbiotic genes, demonstrates that these mutants perhaps define a new set of genes influencing the symbiotic process inRhizobium meliloti.read more
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Key roles of microsymbiont amino acid metabolism in rhizobia-legume interactions
TL;DR: This review summarizes past findings and current research directions in rhizobial amino acid metabolism and evaluates the genetic, biochemical and genome expression studies from which these are derived and the symbiotic roles of individual amino acids in different plant-rhizobia combinations.
Journal ArticleDOI
Infection of soybean and pea nodules by Rhizobium spp. purine auxotrophs in the presence of 5-aminoimidazole-4-carboxamide riboside.
TL;DR: The ability to AICA riboside to promote infection by purine auxotrophs, despite serving as a very poor purine source for these strains, supports the hypothesis that AICAR plays a role in infection other than merely promoting bacterial growth.
Journal ArticleDOI
The Mesorhizobium loti purB Gene Is Involved in Infection Thread Formation and Nodule Development in Lotus japonicus
TL;DR: The purB and purH mutants of Mesorhizobium loti exhibited purine auxotrophy and nodulation deficiency on Lotus japonicus, suggesting that 5-aminoimidazole-4-carboxamide ribonucleotide biosynthesis catalyzed by PurB is required for the establishment of symbiosis.
Journal ArticleDOI
Proteomic analysis of Herbaspirillum seropedicae cultivated in the presence of sugar cane extract.
Fabio Aparecido Cordeiro,Michelle Z. Tadra-Sfeir,Luciano F. Huergo,Fábio O. Pedrosa,Rose A. Monteiro,Emanuel Maltempi de Souza +5 more
TL;DR: The differentially expressed proteins suggest that exposure to sugar cane extract induced metabolic changes and adaptations in H. seropedicae presumably in preparation to establish interaction with the plant.
Journal ArticleDOI
Pleiotropic effects of purine auxotrophy inRhizobium meliloti on cell surface molecules
S. K. Swamynathan,Aqbal Singh +1 more
TL;DR: It is shown that there are multiple changes in the cell surface molecules associated with different purine auxotrophs, and the symbiotic deficiency of purines is likely to be a result of these associated changes on thecell surface.
References
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Journal ArticleDOI
A complementation analysis of the restriction and modification of DNA in Escherichia coli.
TL;DR: Intercistronic complementation was observed between three classes of restriction and modification mutants of E. coli B, indicating that at least three cistron (the ram cistrons) are involved in the genetic control of the [restriction and modification of DNA].
Journal ArticleDOI
Rhizobium-legume nodulation: life together in the underground.
TL;DR: This review concerns a dramatic association, one of the few that has been studied in detail: the nitrogen fixing symbiosis between certain plants and microbes Rhizobium bacteria stimulate leguminous plants to develop root nodules, which the bacteria infect and inhabit.
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A New Method for the Identification of Biochemical Mutants of Micro-organisms
TL;DR: A RAPID method for the identification of biochemical mutants of Ustilago maydis has been devised and is suitable for sporing or non-mycelial micro-organisms which form discrete colonies on agar.
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Genetic analysis of a cluster of genes required for synthesis of the calcofluor-binding exopolysaccharide of Rhizobium meliloti.
TL;DR: Rhizobium meliloti produces an acidic, Calcofluor-binding exopolysaccharide which plays a role in nodulation of alfalfa plants by this bacterium and 102 transposon insertions in a 48-kilobase region previously shown to contain several exo genes are constructed and mapped.
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Sequential Analysis of the Organogenesis of Lucerne (Medicago sativa) Root Nodules Using Symbiotically-Defective Mutants of Rhizobium meliloti
G. Truchet,M. Michel,J. Dénarié +2 more
TL;DR: The role of a bacterial central tissue differentiation inducing principle (CTDIP) which cannot pass from cell to cell is hypothesized, which can cross the plant cell wall and plasmalemma.