title: In planta stage-specific fungal gene profiling elucidates the molecular strategies of Fusarium graminearum growing inside wheat coleoptiles.
abstract: The ascomycete Fusarium graminearum is a destructive fungal pathogen of wheat (Triticum aestivum). To better understand how this pathogen proliferates within the host plant, we tracked pathogen growth inside wheat coleoptiles and then examined pathogen gene expression inside wheat coleoptiles at 16, 40, and 64 h after inoculation (HAI) using laser capture microdissection and microarray analysis. We identified 344 genes that were preferentially expressed during invasive growth in planta. Gene expression profiles for 134 putative plant cell wall-degrading enzyme genes suggest that there was limited cell wall degradation at 16 HAI and extensive degradation at 64 HAI. Expression profiles for genes encoding reactive oxygen species (ROS)-related enzymes suggest that F. graminearum primarily scavenges extracellular ROS before a later burst of extracellular ROS is produced by F. graminearum enzymes. Expression patterns of genes involved in primary metabolic pathways suggest that F. graminearum relies on the glyoxylate cycle at an early stage of plant infection. A secondary metabolite biosynthesis gene cluster was specifically induced at 64 HAI and was required for virulence. Our results indicate that F. graminearum initiates infection of coleoptiles using covert penetration strategies and switches to overt cellular destruction of tissues at an advanced stage of infection.
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
authors.forename: Xiao-Wei
authors.initials: XW
authors.lastname: Zhang
authors.forename: Lei-Jie
authors.initials: LJ
authors.lastname: Jia
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Gang
authors.initials: G
authors.lastname: Jiang
authors.forename: Xuan
authors.initials: X
authors.lastname: Li
authors.forename: Dong
authors.initials: D
authors.lastname: Zhang
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Tang
mesh_terms: D018548:Cotyledon / Q000382:microbiology*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005670:Fusarium / Q000472:pathogenicity*; D020869:Gene Expression Profiling; D014908:Triticum / Q000382:microbiology*
chemical_list: D005656:Fungal Proteins