Three-dimensional ultrastructure of feeding tubes and interconnected endoplasmic reticulum in root-knot nematode-induced giant cells in rose balsam
Three-dimensional ultrastructure of feeding tubes and interconnected endoplasmic reticulum in root-knot nematode-induced giant cells in rose balsam
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DOI：
10.1007/s00709-016-1072-x
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发表时间：
2017-02
期刊：
影响因子：
2.9
通讯作者：
Nao Miyashita;H. Koga
中科院分区：
文献类型：
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作者：
Nao Miyashita;H. Koga
本研究对凤仙花（Impatiens balsaminaL.）采用锇浸渍结合场发射扫描电子显微镜（FE-SEM）技术，对南方根结线虫（Meloidogyne incognita）的根系进行了研究。在35天的老瘿玫瑰香脂植物的根，成年线虫诱导形成的巨细胞含有饲管和众多的细胞器，包括管状内质网（ER），池状ER，和线粒体。饲管被细管状结构（直径20-50 nm）包围，细管状结构又被管状ER（直径约120 nm）包围。细管状结构的末端似乎连接到饲管的表面，表明细管状结构是连续的，在饲管中具有狭窄的通道。管状内质网起源于池状内质网。大束的管状ER存在于饲管附近，在巨细胞的中心，和巨细胞的周边区域，如细胞壁向内生长，而较小束的管状ER在巨细胞中形成网络。这些观察结果表明，在巨细胞中，管状ER起着维管束的作用，促进营养物质的运输。我们在巨细胞中发现了囊状结构（直径30 μm），由光滑的、重复分支的ER小管包裹在几层池状ER中组成。我们建议，脂质和类固醇的合成在顺利分支ER和存储在这些胶囊，直到需要的线虫。
We investigated the three-dimensional ultrastructure of feeding tubes and the surrounding region in giant cells induced in rose balsam (Impatiens balsaminaL.) roots by the root-knot nematodeMeloidogyne incognita, using osmium maceration coupled with field emission scanning electron microscopy (FE-SEM). In the roots of 35-day-old galled rose balsam plants, adult nematodes induced the formation of giant cells containing feeding tubes and numerous organelles, including tubular endoplasmic reticulum (ER), cisternal ER, and mitochondria. The feeding tubes were surrounded by fine tubular structures (20–50 nm in diameter), which were in turn surrounded by tubular ER (approximately 120 nm in diameter). The termini of the fine tubular structures appeared to be connected to the surface of the feeding tubes, suggesting that the fine tubular structures were continuous with narrow channels in the feeding tubes. The tubular ER arose from cisternal ER. Large bundles of tubular ER were present near the feeding tube, in the centers of the giant cells, and in the peripheral regions of the giant cells, such as cell wall ingrowths, while smaller bundles of tubular ER formed networks in the giant cells. These observations suggest that tubular ER functions as vascular bundles in giant cells, facilitating the transport of nutrients. We identified capsule-shaped structures (30 μm in diameter) in the giant cells that consisted of smooth, repeatedly branched ER tubules wrapped in several layers of cisternal ER. We propose that lipids and steroids are synthesized at the smooth branched ER and stored in these capsules until needed by the nematode.