Im Yang Ju, Idkowiak-Baldys Jolanta, Thevissen Karin, Cammue Bruno P A, Takemoto Jon Y
Department of Biology, Utah State University, Logan 84322-5305, USA.
FEMS Microbiol Lett. 2003 Jun 27;223(2):199-203. doi: 10.1016/S0378-1097(03)00375-6.
Both bacterial cyclic lipodepsipeptide syringomycin E and plant defensin DmAMP1 were shown previously to require expression of the yeast gene IPT1 for fungicidal action against Saccharomyces cerevisiae. IPT1 encodes a sphingolipid biosynthetic pathway glycotransferase that produces the terminal sphingolipid mannosyldiinositolphosphoceramide. However, when grown in half-strength potato dextrose medium, an ipt1 deletion mutant of S. cerevisiae was observed to be sensitive to syringomycin E and DmAMP1 and to produce small amounts of mannosyldiinositolphosphoceramide. These results show that the terminal sphingolipid but not IPT1 expression is required for fungicidal activity, and they suggest an IPT1-independent route for mannosyldiinositolphosphoceramide biosynthesis.
先前已表明，细菌环状脂肽类物质丁香霉素E和植物防御素DmAMP1对酿酒酵母的杀真菌作用均需要酵母基因IPT1的表达。IPT1编码一种鞘脂生物合成途径中的糖基转移酶，该酶可产生末端鞘脂甘露糖基二肌醇磷酸神经酰胺。然而，当在半强度马铃薯葡萄糖培养基中生长时，观察到酿酒酵母的ipt1缺失突变体对丁香霉素E和DmAMP1敏感，并产生少量的甘露糖基二肌醇磷酸神经酰胺。这些结果表明，杀真菌活性所需的是末端鞘脂而非IPT1的表达，并且它们提示了一条不依赖IPT1的甘露糖基二肌醇磷酸神经酰胺生物合成途径。
