The evolutionarily conserved serine/threonine kinase TOR recruits different subunits to assemble the Target of Rapamycin Complex 1 (TORC1), which is inhibited by rapamycin and regulates ribosome biogenesis, autophagy, and lipid metabolism by regulating the expression of lipogenic genes. In addition, TORC1 participates in the cell cycle, increasing the length of the G2 phase. In the present work, we investigated the effect of rapamycin on cell growth, cell morphology and neutral lipid metabolism in the phytopathogenic fungus Ustilago maydis. Inhibition of TORC1 by rapamycin induced the formation of septa that separate the nuclei that were formed after mitosis. Regarding neutral lipid metabolism, a higher accumulation of triacylglycerols was not detected, but the cells did contain large lipid bodies, which suggests that small lipid bodies became fused into big lipid droplets. Vacuoles showed a similar behavior as the lipid bodies, and double labeling with Blue-CMAC and BODIPY indicates that vacuoles and lipid bodies were independent organelles. The results suggest that TORC1 has a role in cell morphology, lipid metabolism, and vacuolar physiology in U. maydis.

中文翻译：

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雷帕霉素在不增加黑豆脂质含量的情况下诱导形态和生理变化

进化上保守的丝氨酸/苏氨酸激酶 TOR 招募不同的亚基来组装雷帕霉素靶标复合物 1 (TORC1)，它被雷帕霉素抑制并通过调节脂肪生成基因的表达来调节核糖体生物发生、自噬和脂质代谢。此外，TORC1 参与细胞周期，增加 G2 期的长度。在目前的工作中，我们研究了雷帕霉素对植物病原真菌 Ustilago maydis 中细胞生长、细胞形态和中性脂质代谢的影响。雷帕霉素对TORC1的抑制诱导了隔膜的形成，隔膜将有丝分裂后形成的细胞核分开。关于中性脂质代谢，未检测到更高的三酰甘油积累，但细胞确实含有大的脂质体，这表明小的脂质体融合成大的脂滴。液泡表现出与脂质体相似的行为，用 Blue-CMAC 和 BODIPY 双重标记表明液泡和脂质体是独立的细胞器。结果表明 TORC1 在 U. maydis 的细胞形态、脂质代谢和液泡生理学中起作用。