RESUMO
Rhizobia form nodules on legume roots in which they carry out biological nitrogen fixation. The location and number of nodules is tightly regulated. Exchange of signal molecules that activate responses in the symbiotic partner takes place: plant flavonoids induce the production of rhizobial Nod factors; Nod factors induce gene expression and morphogenesis in the legume root. ENOD40 is a plant gene induced by Nod factors that is involved in root nodule formation. ENOD40 encodes a peptide of 12 amino acids in soya bean that can induce tolerance of high auxin concentrations in tobacco protoplasts.
Assuntos
Proteínas de Membrana , Raízes de Plantas/fisiologia , Transdução de Sinais , Simbiose/fisiologia , Proteínas de Bactérias , Fabaceae/metabolismo , Homeostase , Interações Hospedeiro-Parasita , Lipopolissacarídeos/metabolismo , N-Acetilglucosaminiltransferases/genética , N-Acetilglucosaminiltransferases/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Medicinais , Rhizobium/metabolismoRESUMO
The gene ENOD40 is expressed during early stages of legume nodule development. A homolog was isolated from tobacco, which, as does ENOD40 from legumes, encodes an oligopeptide of about 10 amino acids. In tobacco protoplasts, these peptides change the response to auxin at concentrations as low as 10(-12) to 10(-16)M. The peptides encoded by ENOD40 appear to act as plant growth regulators.
Assuntos
Fabaceae/genética , Genes de Plantas , Ácidos Indolacéticos/farmacologia , Nicotiana/genética , Proteínas de Plantas/genética , Proteínas de Plantas/fisiologia , Plantas Medicinais , Plantas Tóxicas , RNA não Traduzido/fisiologia , Sequência de Aminoácidos , Sequência de Bases , Divisão Celular , Fabaceae/química , Fabaceae/crescimento & desenvolvimento , Proteínas de Fluorescência Verde , Proteínas Luminescentes/biossíntese , Dados de Sequência Molecular , Ácidos Naftalenoacéticos/farmacologia , Fases de Leitura Aberta , Reguladores de Crescimento de Plantas , Proteínas de Plantas/biossíntese , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Protoplastos/citologia , RNA Longo não Codificante , Proteínas Recombinantes de Fusão , Nicotiana/química , Nicotiana/crescimento & desenvolvimento , TransfecçãoRESUMO
A pea cDNA clone representing the homologue of the soybean pGmENOD40-1 was isolated and characterized. At the nucleotide level both clones share 55% homology. Strikingly, the homology between the polypeptides derived from the pea and soybean ENOD40 cDNA sequences is only 14%. Despite this low homology Southern analyses revealed that the isolated pea cDNA clone represents the single pea ENOD40. In situ hybridizations showed that at early stages of nodule development and in mature nodules the expression pattern of pea ENOD40 is comparable to that of soybean ENOD40. Although ENOD40 show similar expression patterns in these two nodules, it is questionable whether the putative polypeptides have a similar function, since the homology is very low.
