Department of Agricultural Biotechnology, Center for Fungal Pathogenesis, Seoul National University, Seoul, Korea.
FEMS Microbiol Lett. 2012 Apr;329(2):123-30. doi: 10.1111/j.1574-6968.2012.02511.x. Epub 2012 Feb 13.
The pyruvate-acetaldehyde-acetate (PAA) pathway has diverse roles in eukaryotes. Our previous study on acetyl-coenzyme A synthetase 1 (ACS1) in Gibberella zeae suggested that the PAA pathway is important for lipid production, which is required for perithecia maturation. In this study, we deleted all three pyruvate decarboxylase (PDC) genes, which encode enzymes that function upstream of ACS1 in the PAA pathway. Results suggest PDC1 is required for lipid accumulation in the aerial mycelia, and deletion of PDC1 resulted in highly wettable mycelia. However, the total amount of lipids in the PDC1 deletion mutants was similar to that of the wild-type strain, likely due to compensatory lipid production processes in the embedded mycelia. PDC1 was expressed both in the aerial and embedded mycelia, whereas ACS1 was observed only in the aerial mycelia in a PDC1-dependent manner. PDC1 is also involved in vegetative growth of embedded mycelia in G. zeae, possibly through initiating the ethanol fermentation pathway. Thus, PDC1 may function as a key metabolic enzyme crucial for lipid production in the aerial mycelia, but play a different role in the embedded mycelia, where it might be involved in energy generation by ethanol fermentation.
丙酮酸-乙醛-乙酸盐（PAA）途径在真核生物中具有多种功能。我们之前对禾谷镰孢菌乙酰辅酶 A 合成酶 1（ACS1）的研究表明，PAA 途径对于脂质生产很重要，这是产子囊壳成熟所必需的。在这项研究中，我们删除了 PAA 途径中 ACS1 上游的三个丙酮酸脱羧酶（PDC）基因。结果表明，PDC1 是气生菌丝中脂质积累所必需的，并且 PDC1 的缺失导致菌丝高度吸湿。然而，PDC1 缺失突变体中的总脂质量与野生型菌株相似，这可能是由于嵌入菌丝中存在补偿性脂质生产过程。PDC1 在气生和嵌入菌丝中均有表达，而 ACS1 仅在 PDC1 依赖的气生菌丝中观察到。PDC1 还参与禾谷镰孢菌嵌入菌丝的营养生长，可能通过启动乙醇发酵途径。因此，PDC1 可能作为气生菌丝中脂质生产的关键代谢酶发挥作用，但在嵌入菌丝中可能参与通过乙醇发酵产生能量。
