title: Histological and cytological characterization of adult plant resistance to wheat stripe rust.
abstract: Wheat cultivar Xingzi 9104 (XZ) possesses adult plant resistance (APR) to stripe rust caused by Puccinia striiformis f. sp. tritici (Pst). In this study, histological and cytological experiments were conducted to elucidate the mechanisms of APR in XZ. The results of leaf inoculation experiments indicated that APR was initiated at the tillering stage, gradually increased as the plant aged and highly expressed after boot stage. The histology and oxidative burst in infected leaves of plants at seedling, tillering and boot stages were examined using light microscopic and histochemical methods. Subcellular changes in the host-pathogen interactions during the seedling and boot stages were analyzed by transmission electron microscopy. The results showed that haustorium formation was retarded in the adult plants and that the differentiation of secondary intercellular hyphae was significantly inhibited, which decreased the development of microcolonies in the adult plants, especially in plants of boot stage. The expression of APR to stipe rust during wheat development was clearly associated with extensive hypersensitive cell death of host cells and localized production of reactive oxygen species, which coincided with the restriction of fungal growth in infection sites in adult plants. At the same time, cell wall-related resistance in adult plants prevented ingression of haustorial mother cells into plant cells. Haustorium encasement was coincident with malformation or death of haustoria. The results provide useful information for further determination of mechanisms of wheat APR to stripe rust.
  
  
  CONCLUSIONS
  The expression of APR to stipe rust in wheat cultivar Xingzi 9104 (XZ) was clearly associated with extensive hypersensitive cell death of host cells and the localized production of reactive oxygen species.
authors: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling 712100, Shaanxi, People's Republic of China.
authors: Hongchang
authors: H
authors: Zhang
authors: Chenfang
authors: C
authors: Wang
authors: Yulin
authors: Y
authors: Cheng
authors: Xianming
authors: X
authors: Chen
authors: Qingmei
authors: Q
authors: Han
authors: Lili
authors: L
authors: Huang
authors: Guorong
authors: G
authors: Wei
authors: Zhensheng
authors: Z
authors: Kang
mesh_terms: D001487:Basidiomycota / Q000472:pathogenicity*; D016923:Cell Death; D060467:Disease Resistance; D006651:Histocytochemistry; D054884:Host-Pathogen Interactions; D006861:Hydrogen Peroxide / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D025282:Mycelium / Q000276:immunology / Q000648:ultrastructure; D010084:Oxidation-Reduction; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology; D018515:Plant Leaves / Q000276:immunology / Q000382:microbiology* / Q000648:ultrastructure; D017382:Reactive Oxygen Species / Q000378:metabolism; D036226:Seedlings / Q000276:immunology / Q000382:microbiology; D013997:Time Factors; D014908:Triticum / Q000166:cytology* / Q000276:immunology / Q000378:metabolism / Q000382:microbiology
chemical_list: D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide