Ultrastructure of rapidly frozen and freeze-substituted germ tubes of an arbuscular mycorrhizal fungus and localization of polyphosphate
Ultrastructure of rapidly frozen and freeze-substituted germ tubes of an arbuscular mycorrhizal fungus and localization of polyphosphate
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DOI：
10.1111/j.1469-8137.2007.02345.x
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发表时间：
2008-01-01
期刊：
影响因子：
9.4
通讯作者：
Saito, Masanori
中科院分区：
文献类型：
--
作者：
Kuga, Yukari;Saito, Katsuharu;Saito, Masanori
在丛枝菌根（AM）中，来自真菌的磷供应是对宿主植物最重要的益处之一。本文首次描述了AM真菌Gigaspora margarita快速冷冻和冷冻替代芽管中的超微结构和多聚磷酸盐（poly P）分布。在超微结构水平上，使用能量过滤透射电子显微镜分析了磷的分布，并使用酶亲和法检测了poly P。半薄切片和活细胞也用4 '，6-二脒基-2-苯基吲哚染色，其不是特异性的，但当在UV照射下通过与聚P结合观察时发黄色荧光。冷冻技术方法表明，含有均匀的电子不透明材料的广泛细长椭圆形空泡占据了大部分细胞体积。综合多种方法的结果表明，poly P以分散的形式定位于液泡和真菌细胞壁的外部，这些结果表明，AM真菌在厚菌丝中广泛存在于液泡中，具有巨大的磷储存潜力。poly P在肾小管液泡中的转运机制以及poly P在细胞壁中的作用有待阐明。
In arbuscular mycorrhizas (AM), the supply of phosphorus from the fungi is one of the most important benefits to the host plant. Here we describe for the first time the ultrastructure and polyphosphate (poly P) distribution in rapidly frozen and freeze-substituted germ tubes of the AM fungus Gigaspora margarita.At the ultrastructural level, phosphorus distribution was analysed using energy-filtering transmission electron microscopy, and poly P was detected using an enzyme-affinity method. Semithin sections and live cells were also stained with 4',6-diamidino-2-phenylindole, which is not specific but fluoresces yellow when viewed under UV irradiation by binding with poly P.The cryotechnique method showed that extensive elongate ellipsoid vacuoles containing a uniform electron-opaque material occupied most of the cell volume. Combining the results of multiple methods revealed that poly P was localized in a dispersed form in vacuoles and in the outer fungal cell wall.These results show the significant potential of AM fungi for phosphorus storage based on its localization in the extensive complement of vacuoles in thick hyphae. The mechanism of translocation of poly P in tubular vacuoles, and the role of poly P in the cell wall, need to be elucidated.