title: Genetic responses induced in olive roots upon colonization by the biocontrol endophytic bacterium Pseudomonas fluorescens PICF7.
abstract: Knowledge on the genetic basis underlying interactions between beneficial bacteria and woody plants is still very limited, and totally absent in the case of olive. We aimed to elucidate genetic responses taking place during the colonization of olive roots by the native endophyte Pseudomonas fluorescens PICF7, an effective biocontrol agent against Verticillium wilt of olive. Roots of olive plants grown under non-gnotobiotic conditions were collected at different time points after PICF7 inoculation. A Suppression Subtractive Hybridization cDNA library enriched in induced genes was generated. Quantitative real time PCR (qRT-PCR) analysis validated the induction of selected olive genes. Computational analysis of 445 olive ESTs showed that plant defence and response to different stresses represented nearly 45% of genes induced in PICF7-colonized olive roots. Moreover, quantitative real-time PCR (qRT-PCR) analysis confirmed induction of lipoxygenase, phenylpropanoid, terpenoids and plant hormones biosynthesis transcripts. Different classes of transcription factors (i.e., bHLH, WRKYs, GRAS1) were also induced. This work highlights for the first time the ability of an endophytic Pseudomonas spp. strain to mount a wide array of defence responses in an economically-relevant woody crop such as olive, helping to explain its biocontrol activity.
authors.affiliation: Departamento de Protección de Cultivos, Instituto de Agricultura Sostenible, Consejo Superior de Investigaciones Científicas (CSIC), Córdoba, Spain.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Schilirò
authors.forename: Massimo
authors.initials: M
authors.lastname: Ferrara
authors.forename: Franco
authors.initials: F
authors.lastname: Nigro
authors.forename: Jesús
authors.initials: J
authors.lastname: Mercado-Blanco
mesh_terms: D053898:Biosynthetic Pathways / Q000235:genetics; D015169:Colony Count, Microbial; D019295:Computational Biology; D060026:Endophytes / Q000502:physiology*; D020224:Expressed Sequence Tags; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D058977:Molecular Sequence Annotation; D008969:Molecular Sequence Data; D031658:Olea / Q000235:genetics* / Q000276:immunology / Q000382:microbiology*; D010572:Pest Control, Biological; D018517:Plant Roots / Q000235:genetics* / Q000276:immunology / Q000382:microbiology*; D020005:Propanols / Q000378:metabolism; D011551:Pseudomonas fluorescens / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D015203:Reproducibility of Results
chemical_list: D020005:Propanols; D012333:RNA, Messenger; C439395:1-phenylpropanol