Evidence for calcium-mediated perception of plant symbiotic signals in aequorin-expressing Mesorhizobium loti.
BMC Microbiol
; 9: 206, 2009 Sep 23.
Article
em En
| MEDLINE
| ID: mdl-19775463
ABSTRACT
BACKGROUND:
During the interaction between rhizobia and leguminous plants the two partners engage in a molecular conversation that leads to reciprocal recognition and ensures the beginning of a successful symbiotic integration. In host plants, intracellular Ca(2+) changes are an integral part of the signalling mechanism. In rhizobia it is not yet known whether Ca(2+) can act as a transducer of symbiotic signals.RESULTS:
A plasmid encoding the bioluminescent Ca(2+) probe aequorin was introduced into Mesorhizobium loti USDA 3147(T) strain to investigate whether a Ca(2+) response is activated in rhizobia upon perception of plant root exudates. We find that M. loti cells respond to environmental and symbiotic cues through transient elevations in intracellular free Ca(2+) concentration. Only root exudates from the homologous host Lotus japonicus induce Ca(2+) signalling and downstream activation of nodulation genes. The extracellular Ca(2+) chelator EGTA inhibits both transient intracellular Ca(2+) increase and inducible nod gene expression, while not affecting the expression of other genes, either constitutively expressed or inducible.CONCLUSION:
These findings indicate a newly described early event in the molecular dialogue between plants and rhizobia and highlight the use of aequorin-expressing bacterial strains as a promising novel approach for research in legume symbiosis.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Simbiose
/
Cálcio
/
Alphaproteobacteria
/
Lotus
Idioma:
En
Ano de publicação:
2009
Tipo de documento:
Article