title: Global transcriptome analysis reveals distinct expression among duplicated genes during sorghum-interaction.
abstract: BACKGROUND
  Sorghum (Sorghum bicolor L. Moench) is a rich source of natural phytochemicals. We performed massive parallel sequencing of mRNA to identify differentially expressed genes after sorghum BTx623 had been infected with Bipolaris sorghicola, a necrotrophic fungus causing a sorghum disease called target leaf spot.
  
  
  RESULTS
  Seventy-six-base-pair reads from mRNAs of mock- or pathogen-infected leaves were sequenced. Unannotated transcripts were predicted on the basis of the piling-up of mapped short reads. Differentially expressed genes were identified statistically; particular genes in tandemly duplicated putative paralogs were highly upregulated. Pathogen infection activated the glyoxylate shunt in the TCA cycle; this changes the role of the TCA cycle from energy production to synthesis of cell components. The secondary metabolic pathways of phytoalexin synthesis and of sulfur-dependent detoxification were activated by upregulation of the genes encoding amino acid metabolizing enzymes located at the branch point between primary and secondary metabolism. Coordinated gene expression could guide the metabolic pathway for accumulation of the sorghum-specific phytochemicals 3-deoxyanthocyanidin and dhurrin. Key enzymes for synthesizing these sorghum-specific phytochemicals were not found in the corresponding region of the rice genome.
  
  
  CONCLUSIONS
  Pathogen infection dramatically changed the expression of particular paralogs that putatively encode enzymes involved in the sorghum-specific metabolic network.
authors: National Institute of Agrobiological Sciences, Agrogenomics Research Center, 1-2, Kannondai 2-chome, Tsukuba, Ibaraki 305-8602, Japan.
authors: Hiroshi
authors: H
authors: Mizuno
authors: Hiroyuki
authors: H
authors: Kawahigashi
authors: Yoshihiro
authors: Y
authors: Kawahara
authors: Hiroyuki
authors: H
authors: Kanamori
authors: Jun
authors: J
authors: Ogata
authors: Hiroshi
authors: H
authors: Minami
authors: Takeshi
authors: T
authors: Itoh
authors: Takashi
authors: T
authors: Matsumoto
mesh_terms: D000872:Anthocyanins / Q000235:genetics / Q000378:metabolism; D001203:Ascomycota / Q000472:pathogenicity; D002952:Citric Acid Cycle; D044950:Flavanones / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D020131:Genes, Duplicate; D017343:Genes, Plant; D054884:Host-Pathogen Interactions; D009570:Nitriles / Q000378:metabolism; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D012717:Sesquiterpenes / Q000378:metabolism; D045868:Sorghum / Q000201:enzymology / Q000235:genetics* / Q000382:microbiology; D000094162:Phytoalexins
chemical_list: D000872:Anthocyanins; D044950:Flavanones; D009570:Nitriles; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D012717:Sesquiterpenes; C005273:naringenin; C011220:dhurrin; D000094162:Phytoalexins