Identification and functional characterization of a glycosylceramide Delta 3-(E) desaturase from phytopathogenic fungi

植物病原真菌中糖基神经酰胺 Delta 3-(E) 去饱和酶的鉴定和功能表征

• 批准号: 5452999
• 负责人: Privatdozent Dr. Dirk Warnecke
• 金额: --
• 依托单位: Biozentrum Klein Flottbek und Botanischer Garten
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2005
• 资助国家: 德国
• 起止时间: 2004-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5452999?language=en
• 关键词: Identification; functional; characterization; glycosylceramide; Delta

Glycosphingolipids are ubiquitous membrane lipids present in all eukaryotic organisms. Their ceramide backbone may be modified in many respects. In mammalian und yeast cells, these lipids are involved in cell cycle progression, apoptosis, pathogen defense and stress response, while in fungi only the effects of glucosylceramides as elicitors and as a target for plant defensins point to similar functions also in these organisms. Some fungal glycosylceramides contain a ¿3-(E)-desaturated fatty acid, the biological function of which is still unknown. A desaturase, which introduces a double bond into the ¿3-position of a fatty acid residue, has not been identified from any organism so far. In the course of our previous research on the cloning of fatty acid and sphingobase desaturases from plants and fungi, we have now identified suitable candidate sequences in the genomes of the phytopathogenic fungi Fusarium gramineum und Magnaporthe grisea in a bioinformatic approach. These sequences most likely code for a glycosylceramide ¿3-(E)-desaturase. Following PCR amplification, the functional identification of these genes should be carried out by heterologous expression in the yeast Pichia pastoris. Moreover, both cerealpathogenic fungi are suitable for a gene knock-out by homologous recombination and as a target for plant defensins. This will enable us to study the function of this ¿3-desaturase in these phytopathogenic fungi and its contribution to their virulence towards cereals such as wheat, barley, maize and rice.

鞘糖脂是存在于所有真核生物中的普遍存在的膜脂质。它们的神经酰胺骨架可以在许多方面进行修饰。在哺乳动物和酵母细胞中，这些脂质参与细胞周期进程、细胞凋亡、病原体防御和应激反应，而在真菌中，仅葡萄糖神经酰胺作为激发子和作为植物防御素的靶点的作用在这些生物体中也指向类似的功能。一些真菌糖基神经酰胺含有一种3-（E）-去饱和脂肪酸，其生物学功能仍然未知。到目前为止，还没有从任何生物体中鉴定出将双键引入脂肪酸残基的3位的去饱和酶。在我们以前的研究过程中，从植物和真菌的脂肪酸和鞘氨醇脱氢酶的克隆，我们现在已经确定了合适的候选序列的基因组中的植物病原真菌禾谷镰刀菌和稻瘟病菌的生物信息学方法。这些序列最有可能编码糖基神经酰胺3-（E）-去饱和酶。PCR扩增后，这些基因的功能鉴定应进行异源表达在酵母巴斯德毕赤酵母。此外，这两种禾谷类病原真菌都适合通过同源重组进行基因敲除，并作为植物防御素的靶标。这将使我们能够研究这种3-去饱和酶在这些植物病原真菌中的功能及其对小麦，大麦，玉米和水稻等谷物的毒力的贡献。