Morphological Studies on Zoospores of Aphanomyces cochlioides and Changes during Interaction with Host Materials
Morphological Studies on Zoospores of Aphanomyces cochlioides and Changes during Interaction with Host Materials
复制标题
线状丝丝菌游动孢子的形态学研究及其与宿主材料相互作用过程中的变化
DOI：
10.1007/pl00013026
复制
发表时间：
2001
影响因子：
1.2
通讯作者：
S. Tahara
中科院分区：
文献类型：
--
作者：
M. Islam;Toshiaki Ito;S. Tahara
利用光学显微镜和电子显微镜研究了螺旋丝壳孢完整游动孢子的行为和形态多样性，以及与寄主和寄主特异性游动孢子引诱剂相互作用时游动孢子形态的动态变化。肾形卵形游动孢子有两个不等鞭毛，都插入腹沟。前鞭毛有两排三部分管状毛（TTH）分布在整个长度，而后鞭毛是由两排高度密集的细管状毛，除了在其锥形的终端部分。后鞭毛的顶端有一束类似鞭毛轴上的细毛。双鞭毛游动孢子在寄主菠菜根上迅速聚集，附着于根表面，通过鞭毛脱落或收缩包囊，定点萌发形成芽管，最后在50-60 min内通过附着胞侵入根组织。Cochlioides游动孢子反映了宿主特异性信号的指导，用于定位潜在的感染位点、游动孢子分化为囊孢子、形成感染结构和/或快速完成感染前事件的芽管向性。在包囊形成之前，后鞭毛可能参与通过尖端接触随后脱落或缩回在牙根表面上的成功对接。
The behavioral and morphological diversity of intact zoospores of Aphanomyces cochlioides and their dynamic morphological changes when interacting with the host or a host-specific zoospore attractant were studied by light and electron microscopy. The reniform-ovate zoospore has two heterokont flagella, both inserted in a ventral groove. The anterior flagellum possesses two rows of tripartite tubular hairs (TTHs) distributed throughout its length, whereas the posterior flagellum was ornamented with two rows of highly dense fine tubular hairs, except on its tapered terminal part. The tip of the posterior flagellum has a bunch of similar fine hairs like those on the flagellum shaft. The biflagellated zoospores quickly aggregated on the host (spinach) root, adhered to the root surface, encysted by shedding or retracting the flagella, germinated at a fixed point to form germ tubes, and finally invaded the root tissues via the appressoria within 50–60 min. This precise homing response of A. cochlioides zoospores reflects guidance by a host-specific signal(s) for locating potential infection sites, differentiation of zoospores to cystospores, formation of infection structures and/or germ-tube tropism for completing pre-infection events in haste. Prior to the encystment, the posterior flagellum may be involved in successful docking on the root surface by tip contact followed by shedding or retraction.