title: Validation of candidate genes putatively associated with resistance to SCMV and MDMV in maize (Zea mays L.) by expression profiling.
abstract: BACKGROUND
  The potyviruses sugarcane mosaic virus (SCMV) and maize dwarf mosaic virus (MDMV) are major pathogens of maize worldwide. Two loci, Scmv1 and Scmv2, have ealier been shown to confer complete resistance to SCMV. Custom-made microarrays containing previously identified SCMV resistance candidate genes and resistance gene analogs were utilised to investigate and validate gene expression and expression patterns of isogenic lines under pathogen infection in order to obtain information about the molecular mechanisms involved in maize-potyvirus interactions.
  
  
  RESULTS
  By employing time course microarray experiments we identified 68 significantly differentially expressed sequences within the different time points. The majority of differentially expressed genes differed between the near-isogenic line carrying Scmv1 resistance locus at chromosome 6 and the other isogenic lines. Most differentially expressed genes in the SCMV experiment (75%) were identified one hour after virus inoculation, and about one quarter at multiple time points. Furthermore, most of the identified mapped genes were localised outside the Scmv QTL regions. Annotation revealed differential expression of promising pathogenesis-related candidate genes, validated by qRT-PCR, coding for metallothionein-like protein, S-adenosylmethionine synthetase, germin-like protein or 26S ribosomal RNA.
  
  
  CONCLUSIONS
  Our study identified putative candidate genes and gene expression patterns related to resistance to SCMV. Moreover, our findings support the effectiveness and reliability of the combination of different expression profiling approaches for the identification and validation of candidate genes. Genes identified in this study represent possible future targets for manipulation of SCMV resistance in maize.
authors.affiliation: Department of Plant Breeding, Technical University of Munich, Freising, Germany. annas_voice2002@yahoo.com
authors.forename: Anna
authors.initials: A
authors.lastname: Uzarowska
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Dionisio
authors.forename: Barbara
authors.initials: B
authors.lastname: Sarholz
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Piepho
authors.forename: Mingliang
authors.initials: M
authors.lastname: Xu
authors.forename: Christina Rønn
authors.initials: CR
authors.lastname: Ingvardsen
authors.forename: Gerhard
authors.initials: G
authors.lastname: Wenzel
authors.forename: Thomas
authors.initials: T
authors.lastname: Lübberstedt
mesh_terms: D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D007113:Immunity, Innate; D020411:Oligonucleotide Array Sequence Analysis; D010935:Plant Diseases / Q000235:genetics* / Q000821:virology; D017800:Potyvirus; D018749:RNA, Plant / Q000235:genetics; D017422:Sequence Analysis, DNA; D013997:Time Factors; D003313:Zea mays / Q000235:genetics* / Q000821:virology
chemical_list: D018749:RNA, Plant