The product of the <i>Rhizobium meliloti ilvC</i> gene is required for isoleucine and valine synthesis and nodulation of alfalfa

Tn5-induced mutants of <i>Rhizobium meliloti</i> that require the amino acids isoleucine and valine for growth on minimal medium were studied. In one mutant, 1028, the defect is associated with an inability to induce nodules on alfalfa. The Tn5 mutation in 1028 is located in a chromosoma...

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Detalles Bibliográficos
Autores principales: Aguilar, Orlando Mario, Grasso, Daniel Horacio
Formato: Articulo
Lenguaje:Inglés
Publicado: 1991
Materias:
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/107831
http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC212565&blobtype=pdf
https://jb.asm.org/content/173/24/7756
Aporte de:
id I19-R120-10915-107831
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
Rhizobium meliloti
Alfalfa
spellingShingle Ciencias Exactas
Rhizobium meliloti
Alfalfa
Aguilar, Orlando Mario
Grasso, Daniel Horacio
The product of the <i>Rhizobium meliloti ilvC</i> gene is required for isoleucine and valine synthesis and nodulation of alfalfa
topic_facet Ciencias Exactas
Rhizobium meliloti
Alfalfa
description Tn5-induced mutants of <i>Rhizobium meliloti</i> that require the amino acids isoleucine and valine for growth on minimal medium were studied. In one mutant, 1028, the defect is associated with an inability to induce nodules on alfalfa. The Tn5 mutation in 1028 is located in a chromosomal 5.5-kb <i>Eco</i>RI fragment.- Complementation analysis with cloned DNA indicated that 2.0 kb of DNA from the 5.5-kb <i>Eco</i>RI fragment restored the wild-type phenotype in the Ilv⁻ Nod⁻ mutant. This region was further characterized by DNA sequence analysis and was shown to contain a coding sequence homologous to those for <i>Escherichia coli</i> DJvC and <i>Saccharomyces cerevisiae</i> Ilv5. Genes <i>ilvC</i> and <i>ilv5</i> code for the enzyme acetohydroxy acid isomeroreductase (isomeroreductase), the second enzyme in the parallel pathways for the biosynthesis of isoleucine and valine. Enzymatic assays confirmed that strain 1028 was a mutant defective in isomeroreductase activity. In addition, it was shown that the <i>ilvC</i> genes of <i>Rhizobium meliloti</i> and <i>E. coli</i> are functionally equivalent. We demonstrated that in <i>ilvC</i> mutant 1028 the common nodulation genes <i>nodABC</i> are not activated by the inducer luteolin. <i>E. coli</i> <i>ilvC</i> complemented both defective properties (Ilv⁻ and Nod⁻) found in mutant 1028. These findings demonstrate that <i>R. meliloti</i> requires an active isomeroreductase enzyme for successful nodulation of alfalfa.
format Articulo
Articulo
author Aguilar, Orlando Mario
Grasso, Daniel Horacio
author_facet Aguilar, Orlando Mario
Grasso, Daniel Horacio
author_sort Aguilar, Orlando Mario
title The product of the <i>Rhizobium meliloti ilvC</i> gene is required for isoleucine and valine synthesis and nodulation of alfalfa
title_short The product of the <i>Rhizobium meliloti ilvC</i> gene is required for isoleucine and valine synthesis and nodulation of alfalfa
title_full The product of the <i>Rhizobium meliloti ilvC</i> gene is required for isoleucine and valine synthesis and nodulation of alfalfa
title_fullStr The product of the <i>Rhizobium meliloti ilvC</i> gene is required for isoleucine and valine synthesis and nodulation of alfalfa
title_full_unstemmed The product of the <i>Rhizobium meliloti ilvC</i> gene is required for isoleucine and valine synthesis and nodulation of alfalfa
title_sort product of the <i>rhizobium meliloti ilvc</i> gene is required for isoleucine and valine synthesis and nodulation of alfalfa
publishDate 1991
url http://sedici.unlp.edu.ar/handle/10915/107831
http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC212565&blobtype=pdf
https://jb.asm.org/content/173/24/7756
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