玉米南方锈病菌的超微结构研究

Ultrastructure Investigation of Southern Corn Rust Fungus(Puccinia polysora Underw)

认识玉米南方锈菌的超微结构特征和侵染过程的细胞学特征,可为南方锈菌致病机理和玉米抗锈机制研究提供重要依据。本研究采集玉米品种‘郑丹958’和‘先玉335’自然发病的南方锈病病叶,4%戊二醛固定液抽气固定,采用扫描电镜和透射电镜技术进行观察。结果表明,玉米南方锈病菌的胞间菌丝呈丝状,胞间菌丝和胞内菌丝细胞核在不同感病玉米品种之间具有单核或者双核的差异;胞间菌丝与寄主细胞接触诱导吸器母细胞的分化,吸器母细胞穿透寄主细胞壁在细胞内形成吸器;寄主细胞质膜在吸器的侵入部位内陷,随着吸器的发育,在吸器颈部周围形成胼胝质并将吸器颈部完全包围起来;夏孢子表面具密致、交错排列的刺突,刺突基部外围存在圆形凹陷的脊。本研究揭示了玉米南方锈菌基本超微结构特征和侵染机构(吸器)细胞学特征,并对其在不同品种细胞内的核相进行了分析,为玉米南方锈菌组织病理学研究奠定重要基础。

The investigation on ultrastructural features and cytological features of infection process for southerncorn rust fungus（Puccinia polysora Underw） would provide an important basis for understanding itspathogenesis and rust resistance mechanisms of maize. The natural infected corn leaves of southern rust fungusfrom two maize varieties‘Zhengdan 958＇and‘Xianyu 335＇were collected and the samples were vacuumedand immobilized using 4% glutaraldehyde. The processed samples were then investigated by scanning electronmicroscopy（SEM） and transmission electron microscopy（TEM）. The results indicated that： the intercellularhyphae of southern corn rust fungus were filiform. The intercellular hyphae and intracellular hyphae haddifference in monokaryon or dicaryon. The contact between the intercellular hyphae and the host cell inducedthe differentiation of haustorial mother cell. The haustoria appeared in the host cell after haustorial mother cellpenetrating through the host cell wall. The host cytoplasmic membrane was invaginated in the place where thehaustoria invaded into the host cell. The callus was generated to surround the haustoria neck with the development of haustoria. The urediospore had the numerous staggered spines on the surface. The rounded andrecessed crista existed on the outside of the spines. The study offered the ultrastructural features andcytological features of infected institutions（haustoria） for southern corn rust fungus, and analyzed the nuclearphases among the different varieties and laid a foundation for the histopathology of southern corn rust fungus.