title: Developmental control of promoter activity is not responsible for mature onset of Cf-9B-mediated resistance to leaf mold in tomato.
abstract: Cf-9 confers resistance to tomato seedlings and mature plants against Cladosporium fulvum races expressing the Avr9 elicitor. It is the central member of a cluster of five paralogous genes in an introgressed segment of chromosome 1 derived from Lycopersicon pimpinellifolium. The other four genes have been named Hcr9-9A, Hcr9-9B, Hcr9-9D, and Hcr9-9E. Hcr9-9B, here designated Cf-9B, encodes weaker resistance than Cf-9, recognizes a different elicitor, and protects only mature plants from infection. The onset of Cf-9B-mediated resistance and the molecular basis for its developmental control were investigated in this study. Fungal inoculation of tomato plants containing reciprocal Cf-9/Cf-9B promoter-coding region swaps, analysis of tomato plants containing promoter-gusA fusions, and a reverse transcriptase-polymerase chain reaction study of Cf-9 and Cf-9B transcripts in tomato plants suggested that transcriptional control of Cf-9B did not account for the late onset of Cf-9B-mediated resistance. Alternative explanations for the onset of Cf-9B-mediated resistance in mature plants are discussed.
authors.affiliation: Research School of Biological Sciences, Australian National University, Canberra, ACT.
authors.forename: S N
authors.initials: SN
authors.lastname: Panter
authors.forename: K E
authors.initials: KE
authors.lastname: Hammond-Kosack
authors.forename: K
authors.initials: K
authors.lastname: Harrison
authors.forename: J D G
authors.initials: JD
authors.lastname: Jones
authors.forename: D A
authors.initials: DA
authors.lastname: Jones
mesh_terms: D001483:Base Sequence; D002963:Cladosporium / Q000254:growth & development*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D007113:Immunity, Innate / Q000235:genetics; D018551:Solanum lycopersicum / Q000235:genetics* / Q000254:growth & development / Q000382:microbiology; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D018515:Plant Leaves / Q000235:genetics / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid
chemical_list: C109609:Cf protein, Lycopersicon esculentum; D008562:Membrane Glycoproteins; D010940:Plant Proteins; D020033:Protein Isoforms