Université de Toulouse, UPS, Surfaces Cellulaires et Signalisation chez les Végétaux, Auzeville, Castanet-Tolosan, France.
Plant Signal Behav. 2010 Mar;5(3):258-60. doi: 10.4161/psb.5.3.10551. Epub 2010 Mar 9.
Oomycetes are a diverse group of filamentous eukaryotic microbes comprising devastating animal and plant pathogens. They share many characteristics with fungi, including polarized hyphal extension and production of spores, but phylogenetics studies have clearly placed oomycetes outside the fungal kingdom, in the kingdom Stramenopila which also includes marine organisms such as diatoms and brown algae. Oomycetes display various specific biochemical features, including sterol metabolism. Sterols are essential isoprenoid compounds involved in membrane function and hormone signaling. Oomycetes belonging to Peronosporales, such as Phytophthora sp., are unable to synthesize their own sterols and must acquire them from their plant or animal hosts. In contrast, a combination of biochemical and molecular approaches allowed us to decipher a nearly complete sterol biosynthetic pathway leading to fucosterol in the legume pathogen Aphanomyces euteiches, an oomycete belonging to Saprolegniales. Importantly, sterol demethylase, a key enzyme from this pathway, is susceptible to chemicals widely used in agriculture and medicine as antifungal drugs, suggesting that similar products could be used against plant and animal diseases caused by Saprolegniales.
卵菌是一类多样化的丝状真核微生物，包括具有破坏性的动植物病原体。它们与真菌有许多共同特征，包括极化菌丝延伸和孢子的产生，但系统发育研究清楚地将卵菌置于真菌界之外，归入不等鞭毛门，不等鞭毛门还包括海洋生物，如硅藻和褐藻。卵菌表现出各种特定的生化特征，包括甾醇代谢。甾醇是参与膜功能和激素信号转导的必需异戊二烯化合物。属于卵菌纲腐霉目的卵菌，如 Phytophthora sp.，不能合成自己的甾醇，必须从植物或动物宿主中获取。相比之下，生化和分子方法的结合使我们能够破译豆科病原体 Aphanomyces euteiches 中几乎完整的甾醇生物合成途径，该途径导致羽扇豆醇的产生，Aphanomyces euteiches 是属于水霉目的卵菌。重要的是，该途径中的关键酶——甾醇脱甲基酶，对农业和医药中广泛用作抗真菌药物的化学物质敏感，这表明类似的产品可用于防治由水霉目引起的植物和动物疾病。
