title: Genome wide profiling of Azospirillum lipoferum 4B gene expression during interaction with rice roots.
abstract: Azospirillum-plant cooperation has been mainly studied from an agronomic point of view leading to a wide description of mechanisms implicated in plant growth-promoting effects. However, little is known about genetic determinants implicated in bacterial adaptation to the host plant during the transition from free-living to root-associated lifestyles. This study aims at characterizing global gene expression of Azospirillum lipoferum 4B following a 7-day-old interaction with two cultivars of Oryza sativa L. japonica (cv. Cigalon from which it was originally isolated, and cv. Nipponbare). The analysis was done on a whole genome expression array with RNA samples obtained from planktonic cells, sessile cells, and root-adhering cells. Root-associated Azospirillum cells grow in an active sessile-like state and gene expression is tightly adjusted to the host plant. Adaptation to rice seems to involve genes related to reactive oxygen species (ROS) detoxification and multidrug efflux, as well as complex regulatory networks. As revealed by the induction of genes encoding transposases, interaction with root may drive bacterial genome rearrangements. Several genes related to ABC transporters and ROS detoxification display cultivar-specific expression profiles, suggesting host specific adaptation and raising the question of A. lipoferum 4B/rice cv. Cigalon co-adaptation.
authors.affiliation: UMR5557 CNRS, Ecologie Microbienne, Université de Lyon, Villeurbanne, France.
authors.forename: Benoît
authors.initials: B
authors.lastname: Drogue
authors.forename: Hervé
authors.initials: H
authors.lastname: Sanguin
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Borland
authors.forename: Claire
authors.initials: C
authors.lastname: Prigent-Combaret
authors.forename: Florence
authors.initials: F
authors.lastname: Wisniewski-Dyé
mesh_terms: D042081:Azospirillum lipoferum / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000382:microbiology*; D018517:Plant Roots / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial
keywords: Azospirillum; cooperation; plant growth-promoting rhizobacteria; rice; transcriptome