title: ERECTA, salicylic acid, abscisic acid, and jasmonic acid modulate quantitative disease resistance of Arabidopsis thaliana to Verticillium longisporum.
abstract: BACKGROUND
  Verticillium longisporum is a soil-borne vascular pathogen infecting cruciferous hosts such as oilseed rape. Quantitative disease resistance (QDR) is the major control means, but its molecular basis is poorly understood so far. Quantitative trait locus (QTL) mapping was performed using a new (Bur×Ler) recombinant inbred line (RIL) population of Arabidopsis thaliana. Phytohormone measurements and analyses in defined mutants and near-isogenic lines (NILs) were used to identify genes and signalling pathways that underlie different resistance QTL.
  
  
  RESULTS
  QTL for resistance to V. longisporum-induced stunting, systemic colonization by the fungus and for V. longisporum-induced chlorosis were identified. Stunting resistance QTL were contributed by both parents. The strongest stunting resistance QTL was shown to be identical with Erecta. A functional Erecta pathway, which was present in Bur, conferred partial resistance to V. longisporum-induced stunting. Bur showed severe stunting susceptibility in winter. Three stunting resistance QTL of Ler origin, two co-localising with wall-associated kinase-like (Wakl)-genes, were detected in winter. Furthermore, Bur showed a much stronger induction of salicylic acid (SA) by V. longisporum than Ler. Systemic colonization was controlled independently of stunting. The vec1 QTL on chromosome 2 had the strongest effect on systemic colonization. The same chromosomal region controlled the level of abscisic acid (ABA) and jasmonic acid (JA) in response to V. longisporum: The level of ABA was higher in colonization-susceptible Ler than in colonization-resistant Bur after V. longisporum infection. JA was down-regulated in Bur after infection, but not in Ler. These differences were also demonstrated in NILs, varying only in the region containing vec1. All phytohormone responses were shown to be independent of Erecta.
  
  
  CONCLUSIONS
  Signalling systems with a hitherto unknown role in the QDR of A. thaliana against V. longisporum were identified: Erecta mediated resistance against V. longisporum-induced stunting. Independent of Erecta, stunting was caused in a light-dependent manner with possible participation of SA and Wakl genes. ABA and JA showed a genotype-specific response that corresponded with systemic colonization by the fungus. Understanding the biological basis of phenotypic variation in A. thaliana with respect to V. longisporum resistance will provide new approaches for implementing durable resistance in cruciferous crops.
authors.affiliation: Freie Universität Berlin, Fachbereich Biologie, Chemie, Pharmazie, Institut für Biologie, Dahlem Centre of Plant Sciences, Angewandte Genetik, Albrecht-Thaer-Weg 6, 14195 Berlin, Germany. haeffner@zedat.fu-berlin.de.
authors.forename: Eva
authors.initials: E
authors.lastname: Häffner
authors.forename: Petr
authors.initials: P
authors.lastname: Karlovsky
authors.forename: Richard
authors.initials: R
authors.lastname: Splivallo
authors.forename: Anna
authors.initials: A
authors.lastname: Traczewska
authors.forename: Elke
authors.initials: E
authors.lastname: Diederichsen
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D017360:Arabidopsis / Q000254:growth & development / Q000382:microbiology* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000378:metabolism*; D003517:Cyclopentanes / Q000378:metabolism*; D060467:Disease Resistance / Q000235:genetics* / Q000528:radiation effects; D005819:Genetic Markers; D007178:Inbreeding; D008027:Light; D009154:Mutation / Q000235:genetics; D054883:Oxylipins / Q000378:metabolism*; D010641:Phenotype; D020161:Physical Chromosome Mapping; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D040641:Quantitative Trait Loci / Q000235:genetics*; D019655:Quantitative Trait, Heritable; D011956:Receptors, Cell Surface / Q000378:metabolism*; D020156:Salicylic Acid / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics / Q000528:radiation effects; D020172:Verticillium / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D005819:Genetic Markers; D054883:Oxylipins; D011956:Receptors, Cell Surface; C011006:jasmonic acid; D000040:Abscisic Acid; C457763:ER protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; D020156:Salicylic Acid