The incompatible combinations between races of Puccinia striiformis and wheat cultivars with low reaction type resistance were examined by means of fluorescent microscopy, differential interference contrast microscopy...The incompatible combinations between races of Puccinia striiformis and wheat cultivars with low reaction type resistance were examined by means of fluorescent microscopy, differential interference contrast microscopy and electron microscopy. The incompatible combinations consisted of wheat cultivar Niuzhute plus CY28, Hybrid46 plus CY29 and Tianxuan882 plus CY29, while the compatible combination was wheat cultivar Huixianhong plus CY28. The observation revealed a striking difference in the fungal development and the host responses between susceptible and resistant wheat cultivars following infection by the pathogen. The main histological manifestation of the pathogen development in the resistant wheat cultivars include inhibition of hyphal growth, delay of hyphal branching and colony formation, decrease of formation of haustorial mother cells and haustoria, and occurrence of host cell necrosis. The observation by electron microscopy demonstrated that a series of abnormal changes occurred in intercellular hyphae, haustorial mother cells and haustoria during pathogen development in the resistant wheat cultivars. The cytoplasm became more electron-dense and vacuoles in the cytoplasm increased in number and size. The cell walls of hyphae, haustorial mother cells were thickened irregularly. The organelles were disorderly distributed in the cytoplasm and the haustorial mother cells and haustoria lost their physiological function. In the final stage of the pathogen development, the intercellular hyphae, haustorial mother cells and haustoria became necrotic and collapsed. The structural defense reactions such as formation of cell wall apposition, collar and encasement of haustorium were essentially more pronounced in the infected wheat leaves of the resistant cultivars than in the susceptible one. In addition, the relationship between the host resistance expression and the histological and cytological features occurred in the incompatible combination was discussed in this paper.展开更多
基金supported by National Natural Science Foundation of China(30070496,30125031)Research Program of Shaanxi Province(2001K02-G4).
文摘The incompatible combinations between races of Puccinia striiformis and wheat cultivars with low reaction type resistance were examined by means of fluorescent microscopy, differential interference contrast microscopy and electron microscopy. The incompatible combinations consisted of wheat cultivar Niuzhute plus CY28, Hybrid46 plus CY29 and Tianxuan882 plus CY29, while the compatible combination was wheat cultivar Huixianhong plus CY28. The observation revealed a striking difference in the fungal development and the host responses between susceptible and resistant wheat cultivars following infection by the pathogen. The main histological manifestation of the pathogen development in the resistant wheat cultivars include inhibition of hyphal growth, delay of hyphal branching and colony formation, decrease of formation of haustorial mother cells and haustoria, and occurrence of host cell necrosis. The observation by electron microscopy demonstrated that a series of abnormal changes occurred in intercellular hyphae, haustorial mother cells and haustoria during pathogen development in the resistant wheat cultivars. The cytoplasm became more electron-dense and vacuoles in the cytoplasm increased in number and size. The cell walls of hyphae, haustorial mother cells were thickened irregularly. The organelles were disorderly distributed in the cytoplasm and the haustorial mother cells and haustoria lost their physiological function. In the final stage of the pathogen development, the intercellular hyphae, haustorial mother cells and haustoria became necrotic and collapsed. The structural defense reactions such as formation of cell wall apposition, collar and encasement of haustorium were essentially more pronounced in the infected wheat leaves of the resistant cultivars than in the susceptible one. In addition, the relationship between the host resistance expression and the histological and cytological features occurred in the incompatible combination was discussed in this paper.
