Early recognition in the <i>Rhizobium meliloti</i>-alfalfa symbiosis: root exudate factor stimulates root adsorption of homologous rhizobia

Adsorption of <i>Rhizobium meliloti</i> to alfalfa roots before their infection and nodule formation shows the specificity of the symbiotic association (G. Caetano-Anolles and G. Favelukes, Appl. Environ. Microbiol. 52:377-382, 1986). The time course of specific adsorption of <i>R....

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Detalles Bibliográficos
Autores principales: Wall, Luis Gabriel, Favelukes, Gabriel
Formato: Articulo
Lenguaje:Inglés
Publicado: 1991
Materias:
Ciencias Exactas
Biología
Rhizobium meliloti
alfalfa
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/107947
http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC207963&blobtype=pdf
https://jb.asm.org/content/173/11/3492
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-107947
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Exactas
Biología
Rhizobium meliloti
alfalfa
spellingShingle Ciencias Exactas
Biología
Rhizobium meliloti
alfalfa
Wall, Luis Gabriel
Favelukes, Gabriel
Early recognition in the <i>Rhizobium meliloti</i>-alfalfa symbiosis: root exudate factor stimulates root adsorption of homologous rhizobia
topic_facet Ciencias Exactas
Biología
Rhizobium meliloti
alfalfa
description Adsorption of <i>Rhizobium meliloti</i> to alfalfa roots before their infection and nodule formation shows the specificity of the symbiotic association (G. Caetano-Anolles and G. Favelukes, Appl. Environ. Microbiol. 52:377-382, 1986). The time course of specific adsorption of <i>R. meliloti</i> (10<sup>3</sup> to 10<sup>4</sup> cells per ml) to roots shows an initial lag period of 3 h, suggesting that either or both symbionts must become conditioned for the adsorption process. Preincubation of <i>R. meliloti</i> L5-30 for 3 h with dialyzed alfalfa root exudate (RE) markedly increased early adsorption of rhizobia to alfalfa roots. The activity in RE was linked to a nondialyzable, thermolabile, trypsin-sensitive factor(s), very different from the root-exuded flavonoid compounds also involved in early <i>Rhizobium</i>-legume interactions. The lack of activity in the RE from plants grown in 5 mM N0<sub>3</sub>⁻ suggested its negative regulation by the nitrogen nutritional status of the plant. Preincubation of <i>R. meliloti</i> with heterologous clover RE did not stimulate adsorption of rhizobial cells to roots. A short pretreatment of RE with homologous (but not heterologous) strains eliminated the stimulatory activity from solution. The stimulation of adsorption of <i>R. meliloti</i> to alfalfa roots was strongly dependent on the growth phase of the rhizobia, being greater at the late exponential stage. Nevertheless, the capacity of <i>R. meliloti</i> L5-30 to eliminate from solution the stimulatory activity in RE appeared to be constitutive in the rhizobia. The low concentration of rhizobial cells used in these experiments was critical to detect the stimulation of adsorption. The early interaction of spontaneously released alfalfa root macromolecular factor(s) and free-living <i>R. meliloti</i>, which shows the specificity and regulatory properties characteristic of infection and nodulation, would be an initial recognition event in the rhizosphere which triggers the process of symbiotic association.
format Articulo
Articulo
author Wall, Luis Gabriel
Favelukes, Gabriel
author_facet Wall, Luis Gabriel
Favelukes, Gabriel
author_sort Wall, Luis Gabriel
title Early recognition in the <i>Rhizobium meliloti</i>-alfalfa symbiosis: root exudate factor stimulates root adsorption of homologous rhizobia
title_short Early recognition in the <i>Rhizobium meliloti</i>-alfalfa symbiosis: root exudate factor stimulates root adsorption of homologous rhizobia
title_full Early recognition in the <i>Rhizobium meliloti</i>-alfalfa symbiosis: root exudate factor stimulates root adsorption of homologous rhizobia
title_fullStr Early recognition in the <i>Rhizobium meliloti</i>-alfalfa symbiosis: root exudate factor stimulates root adsorption of homologous rhizobia
title_full_unstemmed Early recognition in the <i>Rhizobium meliloti</i>-alfalfa symbiosis: root exudate factor stimulates root adsorption of homologous rhizobia
title_sort early recognition in the <i>rhizobium meliloti</i>-alfalfa symbiosis: root exudate factor stimulates root adsorption of homologous rhizobia
publishDate 1991
url http://sedici.unlp.edu.ar/handle/10915/107947
http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC207963&blobtype=pdf
https://jb.asm.org/content/173/11/3492
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