title: Deciphering the transcriptional regulation and spatiotemporal distribution of immunity response in barley to Pyrenophora graminea fungal invasion.
abstract: BACKGROUND
  Barley leaf stripe disease, caused by the fungus Pyrenophora graminea (Pg), is a worldwide crop disease that results in significant loss of barley yield. The purpose of the present work was to use transcriptomic profiling to highlight barley genes and metabolic pathways affected or altered in response to Pg infection and consequently elucidate their involvement and contribution in resistance to leaf stripe.
  
  
  RESULTS
  Our study examined and compared the transcriptomes of two barley genotypes using an established differential display reverse-transcription polymerase chain reaction (DDRT-PCR) strategy at 14 and 20 days post-inoculation (dpi). A total of 54 significantly modulated expressed sequence tags (ESTs) were identified. The analysis of gene expression changes during the course of infection with Pg suggested the involvement of 15 upregulated genes during the immunity response. By using network-based analyses, we could establish a significant correlation between genes expressed in response to Pg invasion. Microscopic analysis and quantitative PCR (qPCR) profiling of callose synthase and cellulose synthases revealed a direct involvement of cell wall reinforcement and callose deposition in the Pg-resistant phenotype.
  
  
  CONCLUSIONS
  We have identified a number of candidate genes possibly involved in the host-pathogen interactions between barley and Pg fungus, 15 of which are specifically expressed in Pg-resistant plants. Collectively, our results suggest that the resistance to leaf stripe in barley proceeds through callose deposition and different oxidation processes.
authors.affiliation: Laboratory of Plant Functional Genomics, Division of Plant Pathology, Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), P.O. Box 6091, Damascus, Syria. ahmedghannam@hotmail.com.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Ghannam
authors.affiliation: Laboratory of Plant Functional Genomics, Division of Plant Pathology, Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), P.O. Box 6091, Damascus, Syria.
authors.forename: Houda
authors.initials: H
authors.lastname: Alek
authors.affiliation: Laboratory of Plant Functional Genomics, Division of Plant Pathology, Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), P.O. Box 6091, Damascus, Syria.
authors.forename: Sanaa
authors.initials: S
authors.lastname: Doumani
authors.affiliation: Laboratory of Plant Functional Genomics, Division of Plant Pathology, Department of Molecular Biology and Biotechnology, Atomic Energy Commission of Syria (AECS), P.O. Box 6091, Damascus, Syria.
authors.forename: Doureid
authors.initials: D
authors.lastname: Mansour
authors.affiliation: Laboratory Plant Disease, Division of Plant Pathology, Department of Molecular Biology and Biotechnology, AECS, P.O. Box 6091, Damascus, Syria.
authors.forename: Mohamad I E
authors.initials: MI
authors.lastname: Arabi
mesh_terms: D001203:Ascomycota; D060467:Disease Resistance / Q000235:genetics*; D020224:Expressed Sequence Tags; D063990:Gene Ontology; D017343:Genes, Plant; D005838:Genotype; D001467:Hordeum / Q000235:genetics* / Q000382:microbiology; D054884:Host-Pathogen Interactions / Q000235:genetics*; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology
keywords: Callose deposition; Differential display; Expressed sequence tags; Hordeum vulgare; Leaf stripe; Pyrenophora graminea; Transcriptional gene networking