title: Quantitative analysis of the naringenin-inducible proteome in Rhizobium leguminosarum by isobaric tagging and mass spectrometry.
abstract: The rhizobium-legume interaction is a critical cornerstone of crop productivity and environmental sustainability. Its potential improvement relies on elucidation of the complex molecular dialogue between its two partners. In the present study, the proteomic patterns of gnotobiotic cultures of Rhizobium leguminosarum bv. viciae 3841 grown for 6 h in presence or absence of the nod gene-inducing plant flavonoid naringenin (10 μM) were analyzed using the iTRAQ approach. A total of 1334 proteins were identified corresponding to 18.67% of the protein-coding genes annotated in the sequenced genome of bv. viciae 3841. The abundance levels of 47 proteins were increased upon naringenin treatment showing fold change ratios ranging from 1.5 to 25 in two biological replicates. Besides the nod units, naringenin enhanced the expression of a number of other genes, many of which organized in operons, including β(1-2) glucan production and secretion, succinoglycan export, the RopA outer membrane protein with homology to an oligogalacturonide-specific porin motif, other enzymes for carbohydrate and amino acid metabolism, and proteins involved in the translation machinery. Data were validated at the transcriptional and phenotypic levels by RT-PCR and an assay of secreted sugars in culture supernatants, respectively. The current approach provides not only a high-resolution analysis of the prokaryotic proteome but also unravels the rhizobium molecular dialogue with legumes by detecting the enhanced expression of several symbiosis-associated proteins, whose flavonoid-dependency had not yet been reported.
authors.affiliation: Department of Agronomy, Food, Natural Resources, Animals and Environment, DAFNAE, Legnaro, Padova, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Tolin
authors.forename: Giorgio
authors.initials: G
authors.lastname: Arrigoni
authors.forename: Roberto
authors.initials: R
authors.lastname: Moscatiello
authors.forename: Antonio
authors.initials: A
authors.lastname: Masi
authors.forename: Lorella
authors.initials: L
authors.lastname: Navazio
authors.forename: Gaurav
authors.initials: G
authors.lastname: Sablok
authors.forename: Andrea
authors.initials: A
authors.lastname: Squartini
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002241:Carbohydrates / Q000032:analysis; D044950:Flavanones / Q000494:pharmacology*; D007553:Isotope Labeling; D013058:Mass Spectrometry; D010446:Peptide Fragments / Q000032:analysis / Q000737:chemistry; D016133:Polymerase Chain Reaction; D020543:Proteome / Q000032:analysis / Q000187:drug effects; D040901:Proteomics / Q000379:methods*; D015203:Reproducibility of Results; D016961:Rhizobium leguminosarum / Q000187:drug effects* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D002241:Carbohydrates; D044950:Flavanones; D010446:Peptide Fragments; D020543:Proteome; C005273:naringenin
keywords: Naringenin; Nitrogen fixation; Plant proteomics; Rhizobium leguminosarum; iTRAQ plant-microbe interactions