title: Effects of an inducible aiiA gene on disease resistance in Eucalyptus urophylla × Eucalyptus grandis.
abstract: N-acyl-homoserine lactones (AHLs) are metabolites of mostly gram-negative bacteria and are critical signaling molecules in bacterial quorum-sensing systems. At threshold concentrations, AHLs can activate the expression of pathogenic genes and induce diseases. Therefore, reducing AHL concentrations is a key point of disease control in plants. AHL-lactonase, which is expressed by aiiA, is widespread in Bacillus sp and can hydrolyze AHLs. In the present study, we cloned aiiA from Bacillus subtilis by PCR. A plant expression vector of aiiA was constructed and name Pcam-PPP3-aiiA, in which expression of aiiA was controlled by the pathogen-inducible plant promoter PPP3. The recombinant plasmid was transferred into Eucalyptus × urophylla × E. grandis by an Agrobacterium-mediated transformation. PCR and Southern blotting showed that aiiA was successfully integrated into the E. urophylla × E. grandis genome and its expression was induced by Ralstonia solanacearum 12 h after inoculation, as shown by reverse transcription-PCR. The transcription efficacy of aiiA increased 43.88-, 30.65-, and 18.95-fold after inoculation with R. solanacearum, Erwinia carotovora ssp. zeae (Sabet) and Cylindrocladium quinqueseptatum, respectively as shown by RT-real-time PCR. Transgenic E.urophylla × E.grandis expressing the AIIA protein exhibited significantly enhanced disease resistance compared to non-transgenic plants by delaying the onset of wilting and reducing the disease index.
authors.affiliation: Guangdong University of Petrochemical Technology, Maoming, 525000, China. ouyanglejun@163.com.
authors.forename: L J
authors.initials: LJ
authors.lastname: Ouyang
authors.affiliation: Guangdong University of Petrochemical Technology, Maoming, 525000, China.
authors.forename: L M
authors.initials: LM
authors.lastname: Li
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism; D060467:Disease Resistance / Q000235:genetics*; D004798:Enzymes / Q000378:metabolism; D005052:Eucalyptus / Q000235:genetics* / Q000382:microbiology; D018506:Gene Expression Regulation, Plant; D008666:Metalloendopeptidases / Q000235:genetics* / Q000378:metabolism; D016973:Pectobacterium carotovorum / Q000472:pathogenicity; D010838:Phytophthora / Q000472:pathogenicity; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology*; D030821:Plants, Genetically Modified / Q000235:genetics* / Q000382:microbiology; D016133:Polymerase Chain Reaction; D043368:Ralstonia solanacearum / Q000472:pathogenicity; D046509:Tissue Culture Techniques
chemical_list: D001426:Bacterial Proteins; D004798:Enzymes; D002265:Carboxylic Ester Hydrolases; C432003:N-acyl homoserine lactonase; C406735:AiiA protein, Bacillus; D008666:Metalloendopeptidases
keywords: Broad-spectrum disease resistance; Eucalyptus urophylla × E. grandis; Genetic transformation; Inducible expression; aiiA