Roles of phospholipid methyltransferases in pycnidia development, stress tolerance and secondary metabolism in the taxol-producing fungus Pestalotiopsis microspore
Roles of phospholipid methyltransferases in pycnidia development, stress tolerance and secondary metabolism in the taxol-producing fungus Pestalotiopsis microspore
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磷脂甲基转移酶在紫杉醇生产真菌拟盘拟盘菌小孢子分生孢子器发育、胁迫耐受和次生代谢中的作用
DOI：
10.1016/j.micres.2018.03.001
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发表时间：
2018-01-01
影响因子：
6.7
通讯作者：
Zhu, Xudong
中科院分区：
文献类型：
--
作者：
Akhberdi, Oren;Zhang, Qian;Zhu, Xudong
磷脂酰胆碱（PC）是真核细胞重要的膜成分。在酵母菌中，两种磷脂甲基转移酶催化磷脂酰乙醇胺形成磷脂酰胆碱的连续甲基化步骤。然而，磷脂甲基转移酶在丝状真菌中的作用仍然很少被研究。我们在这里报道了两个基因的特征，choA和choC，推定编码磷脂甲基转移酶的紫杉醇生产真菌拟多毛孢小孢子。choC的缺失导致了PC的产生、营养生长和无性结构发育的缺陷。突变菌株表现出多种形态异常，如菌丝尖端肿胀，菌丝分支增强，甚至菌丝自溶。这些基因的一些新作用也被揭示出来，例如choC或choA的缺失会损害胞裂和分生孢子的发育，以及细胞壁的完整性。突变菌株对胁迫条件，如渗透胁迫、低温和金属离子表现出超敏感性。渗透性超敏反应表明PC通路与其他信号通路（如HOG通路）之间存在串扰。此外，choA，而不是choC，是次要代谢物（如拟盘肽内酯B）的产生所必需的，这表明这两个基因的作用不同。这项工作将有助于更好地了解真菌中磷脂甲基转移酶的功能。
Phosphatidylcholine (PC) is an important membrane component of the eukaryotic cell. In yeast fungi, two phospholipid methyltransferases catalyze consecutive steps of methylation in the formation of phosphatidylcholine from phosphatidylethanolamine. However, roles of phospholipid methyltransferases in filamentous fungi remains less investigated. We report here the characterization of two genes, choA and choC, that putatively encoded phospholipid methyltransferases in the taxol-producing fungus Pestalotiopsis microspora. Deletion of choC resulted in defects in PC production, vegetative growth and development of asexual structure. The mutant strains exhibited multiple morphological abnormalities, e.g. swollen hyphal tips and enhanced hyphal branching, and even mycelial autolysis. Some novel roles for the genes were also revealed, for instance, the deletion of either choC or choA impaired the development of pycnidia and conidia, the cell wall integrity. The mutant strains displayed a hypersensitivity to stress conditions, e.g. osmotic stress, cold and metal ions. The osmotic hypersensitivity indicates a crosstalk of PC pathways to other signaling pathways, such as the HOG pathway. Still more, choA, but not choC, was required for the production of secondary metabolites, e.g. pestalotiollide B, suggesting distinct roles of the two genes. This work would contribute to better understanding the function of phospholipid methyltransferases in fungi.