Yu T, Nassuth A, Peterson R L
Department of Botany, University of Guelph, ON, Canada.
Can J Microbiol. 2001 Aug;47(8):741-53. doi: 10.1139/w01-065.
Phialocephala fortinii Wang & Wilcox is a member of root-inhabiting fungi known collectively as dark septate endophytes (DSE). Although very common and distributed worldwide, few studies have documented their interaction with roots on a structural basis. The objective of this study was to determine the early colonization events and formation of microsclerotia of P. fortinii in roots of Asparagus officinalis L., a species known to have DSE. A loose network of hyphae accumulated at the root surface, and coils formed around root hairs and external to epidermal cells overlying short cells of the dimorphic, suberized exodermis. Root penetration occurred via swollen, appressorium-like structures into epidermal cells where coiling of hyphae occurred along the periphery of the cells. Hyphae penetrated from the epidermis into short exodermal cells and from these into cortical cells. Hyphae colonized the cortex up to the endodermis and sometimes entered the vascular cylinder. Some root tips were colonized as well. Microsclerotia in epidermal and exodermal short cells accumulated glycogen, protein, and polyphosphate. Energy-dispersive X-ray spectroscopy on distinct bodies visible in microsclerotial hyphae revealed high levels of phosphorus.
福氏瓶霉（Phialocephala fortinii Wang & Wilcox）是一类统称为深色有隔内生真菌（DSE）的根际真菌成员。尽管这类真菌非常常见且分布于全球，但很少有研究从结构层面记录它们与根的相互作用。本研究的目的是确定福氏瓶霉在芦笋（Asparagus officinalis L.）根中的早期定殖事件以及微菌核的形成，芦笋是一种已知含有DSE的植物。在根表面积累了松散的菌丝网络，并且在根毛周围以及覆盖双态栓质化外皮层短细胞的表皮细胞外部形成了菌丝圈。通过肿胀的、类似附着胞的结构穿透表皮细胞，菌丝在细胞周边发生卷曲。菌丝从表皮穿透进入外皮层短细胞，并从这些细胞进入皮层细胞。菌丝在皮层中定殖直至内皮层，有时还会进入维管束。一些根尖也被定殖。表皮和外皮层短细胞中的微菌核积累了糖原、蛋白质和多聚磷酸盐。对微菌核菌丝中可见的不同物体进行能量色散X射线光谱分析，结果显示磷含量很高。
