title: Colonization of rice leaf blades by an African strain of Xanthomonas oryzae pv. oryzae depends on a new TAL effector that induces the rice nodulin-3 Os11N3 gene.
abstract: African strains of Xanthomonas oryzae pv. oryzae contain fewer TAL effectors than Asian strains, and their contribution to pathogenicity is unknown. Systematic mutagenesis of tal genes was used to decipher the contribution of each of the eight TAL effector paralogs to pathogenicity of African X. oryzae pv. oryzae BAI3. A strain mutated in talC was severely affected in the production of disease symptoms. Analysis of growth in planta upon leaf-clip inoculation showed that mutant bacteria multiplied only at the site of inoculation at the apex of the leaf, suggesting a requirement for talC during colonization of vascular tissues. Such tissue-specific effect of a tal mutant is a novel phenotype, which has not yet been characterized in other xanthomonads. Microarray experiments comparing the host response of rice leaves challenged with BAI3(R) vs. BAI3(R)ΔtalC were performed to identify genes targeted by TalC. A total of 120 upregulated and 21 downregulated genes were identified, among them Os11N3, which is a member of the MtN3/saliva family. Based on semiquantitative reverse transcription-polymerase chain reaction and β-glucuronidase reporter assays, we show that Os11N3 is directly upregulated by TalC and identify a TalC DNA target box within the Os11N3 upstream sequence.
authors.affiliation: Laboratoire Genome et Developpement des Plantes, Montpellier, France.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Yu
authors.forename: Jana
authors.initials: J
authors.lastname: Streubel
authors.forename: Sandrine
authors.initials: S
authors.lastname: Balzergue
authors.forename: Antony
authors.initials: A
authors.lastname: Champion
authors.forename: Jens
authors.initials: J
authors.lastname: Boch
authors.forename: Ralf
authors.initials: R
authors.lastname: Koebnik
authors.forename: Jiaxun
authors.initials: J
authors.lastname: Feng
authors.forename: Valérie
authors.initials: V
authors.lastname: Verdier
authors.forename: Boris
authors.initials: B
authors.lastname: Szurek
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D015536:Down-Regulation; D015964:Gene Expression Regulation, Bacterial; D005966:Glucuronidase; D008565:Membrane Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000235:genetics* / Q000382:microbiology; D010802:Phylogeny; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D017422:Sequence Analysis, DNA; D059467:Transcriptome; D015854:Up-Regulation; D014774:Virulence; D014974:Xanthomonas / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D010940:Plant Proteins; C045625:nodulin; D005966:Glucuronidase