Lipid Droplets of Arbuscular Mycorrhizal Fungi Emerge in Concert with Arbuscule Collapse
Lipid Droplets of Arbuscular Mycorrhizal Fungi Emerge in Concert with Arbuscule Collapse
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DOI：
10.1093/pcp/pcu123
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发表时间：
2014-11-01
影响因子：
4.9
通讯作者：
Hata, Shingo
中科院分区：
文献类型：
--
作者：
Kobae, Yoshihiro;Gutjahr, Caroline;Hata, Shingo
植物与丛枝菌根真菌共享光合固定碳以维持其生长和营养。AM真菌是产油真菌，在其大部分生活史中，其合胞菌丝体中含有大量脂滴。这些脂滴可能用于支持根外菌丝体的生长和繁殖;然而，何时何地产生脂滴仍不清楚。为了解决这些问题，我们研究了细胞内定植阶段和真菌脂滴在根中的外观相结合的真菌结构，选择性染色的脂质和活成像的重要染色之间的相关性。我们发现，脂滴的激增与丛枝的崩溃相一致，表明丛枝的崩溃和脂滴的出现可能是相关的过程。在模式AM真菌Rhizophagus irregularis和AM真菌Paraglomus occultum的祖先成员中观察到这种现象。由于塌陷的丛枝没有代谢活性，因此出现的脂滴可能来自预先形成的脂质，而不是从头合成的。我们的观察突出了AM真菌释放脂质的一种新模式。
Plants share photosynthetically fixed carbon with arbuscular mycorrhizal (AM) fungi to maintain their growth and nutrition. AM fungi are oleogenic fungi that contain numerous lipid droplets in their syncytial mycelia during most of their life cycle. These lipid droplets are probably used for supporting growth of extraradical mycelia and propagation; however, when and where the lipid droplets are produced remains unclear. To address these issues, we investigated the correlation between intracellular colonization stages and the appearance of fungal lipid droplets in roots by a combination of vital staining of fungal structures, selective staining of lipids and live imaging. We discovered that a surge of lipid droplets coincided with the collapse of arbuscular branches, indicating that arbuscule collapse and the emergence of lipid droplets may be associated processes. This phenomenon was observed in the model AM fungus Rhizophagus irregularis and the ancestral member of AM fungi Paraglomus occultum. Because the collapsing arbuscules were metabolically inactive, the emerged lipid droplets are probably derived from preformed lipids but not de novo synthesized. Our observations highlight a novel mode of lipid release by AM fungi.