The nodC, nodG, and glgX genes of Rhizobium tropici strain PRF 81.
Rhizobium tropici is a diazotrophic microsymbiont of common bean (Phaseolus vulgaris L.) that encompasses important but still poorly studied tropical strains, and a recent significant contribution to the knowledge of the species was the publication of a genomic draft of strain PRF 81, which revealed several novel genes [Pinto et al. Funct Int Gen 9:263-270, 2009]. In this study, we investigated the transcription of nodC, nodG, and glgX genes, located in the nod operon of PRF 81 strain, by reverse-transcription quantitative PCR. All three genes showed low levels of transcription when the cells were grown until exponential growth phase in the presence of common-bean-seed exudates or of the root nod-gene inducer naringenin. However, when cells at the exponential phase of growth were incubated with seed exudates, transcription occurred after only 5 min, and nodC, nodG, and glgX were transcribed 121.97-, 14.86-, and 50.29-fold more than the control, respectively, followed by a rapid decrease in gene transcription. Much lower levels of transcription were observed in the presence of naringenin; furthermore, maximum transcription required 8 h of incubation for all three genes. In light of these results, the mechanisms of induction of the nodulation genes by flavonoids are discussed.
Oliveira
Luciana Ruano
LR
Embrapa Soja, Cx. Postal 231, CEP 86001-970, Londrina, Paraná, Brazil. lu_ruano@hotmail.com
Marcelino
Francismar Corrêa
FC
Barcellos
Fernando Gomes
FG
Rodrigues
Elisete Pains
EP
Megías
Manuel
M
Hungria
Mariangela
M
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D044950:Flavanones / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D005798:Genes, Bacterial / Q000235:genetics*; D053147:Plant Exudates / Q000494:pharmacology; D042162:Rhizobium tropici / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D014158:Transcription, Genetic / Q000187:drug effects
D001426:Bacterial Proteins; D044950:Flavanones; D053147:Plant Exudates; C005273:naringenin