Cytology and ultrastructure of the infection of wheat spikes by Fusarium culmorum
Cytology and ultrastructure of the infection of wheat spikes by Fusarium culmorum
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DOI：
10.1017/s0953756200002495
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发表时间：
2000-09-01
影响因子：
--
通讯作者：
Buchenauer, H
中科院分区：
文献类型：
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作者：
Kang, ZS;Buchenauer, H
通过光学显微镜和电子显微镜检查了小麦赤霉病菌（小麦赤霉病的病原体之一）对小麦穗的感染。大分生孢子在接种后6-12 h在所有接触的寄主表面均可萌发。发育中的芽管不会立即感染宿主组织，但会产生菌丝，在宿主表面生长并分枝。接种后2d（dpi），在外稃、颖片和内稃的内表面形成菌丝网络，而在外稃、颖片和轴的外表面不形成菌丝网络。外稃和颖片外表面上的菌丝经常越过边缘长到内表面。在外稃、颖片和内稃的内表面以及子房的上部，感染菌丝可穿透寄主组织。有时，病原菌通过内表面的气孔开口侵入寄主组织。此后，病原菌从上述感染组织通过胞间和胞内生长向下传播到小穗轴和轴节。菌丝从轴节向下延伸到轴，向上通过维管束和皮层薄壁组织延伸到花序梗。当病原菌到达花序轴后4-5 dpi，菌丝在花序轴的维管束和皮层薄壁组织中沿细胞间和细胞内向上和向下生长。在麦穗定殖过程中，宿主组织发生了一系列变化，包括宿主细胞质和细胞器的退化、薄壁细胞的塌陷、宿主细胞壁的解体或消化以及导管壁出现电子致密的涂层材料。
The infection of wheat spikes by Fusarium culmorum, one of the agents responsible for wheat head blight, was examined by light and electron microscopy. Macroconidia of the pathogen germinated 6-12 h after inoculation on all host surfaces they contacted. Developing germ tubes did not infect host tissues immediately, but gave rise to hyphae that grew and branched on host surfaces. Hyphal networks were usually formed 2 d after inoculation (dpi) on the inner surfaces of lemma, glume and palea, but not on the outer surfaces of lemma, glume and rachis. Hyphae on the outer surfaces of lemma and glume often grew over their edges to reach their inner surfaces. Penetration of host tissues occurred by infection hyphae on the inner surfaces of lemma, glume and palea, and on the upper part of the ovary. Occasionally, the pathogen invaded the host tissues through stomatal openings on the inner surface. Thereafter, the pathogen spread downwards to rachilla and rachis node by inter- and intracellular growth from above infected tissues. From the rachis node, hyphae extended downward to rachis and upward to peduncle through vascular bundles and cortical parenchyma tissue. When the pathogen arrived at the rachis 4-5 dpi, hyphae grew upwards and downwards inter- and intracellularly in vascular bundles and cortical parenchyma tissue of the rachis. During colonisation of the wheat spike, a series of alterations occurred in host tissues, including degeneration of host cytoplasm and organelles, collapse of parenchyma cells, disintegration or digestion of host cell walls and appearance of electron-dense coating materials on vessel walls.