Soylu E Mine, Soylu Soner, Kurt Sener
Department of Plant Protection, Faculty of Agriculture, Mustafa Kemal University, 31034, Antakya-Hatay, Turkey.
Mycopathologia. 2006 Feb;161(2):119-28. doi: 10.1007/s11046-005-0206-z.
The aim of this study was to find an alternative to synthetic fungicides currently used in the control of devastating oomycete pathogen Phytophthora infestans, causal agent of late blight disease of tomato. Antifungal activities of essential oils obtained from aerial parts of aromatic plants such as oregano (Origanum syriacum var. bevanii), thyme (Thymbra spicata subsp. spicata), lavender (Lavandula stoechas subsp. stoechas), rosemary (Rosmarinus officinalis), fennel (Foeniculum vulgare), and laurel (Laurus nobilis), were investigated against P. infestans. Both contact and volatile phase effects of different concentrations of the essential oils used were determined by using two in vitro methods. Chemical compositions of the essential oils were also determined by GC-MS analysis. Major compounds found in essential oils of thyme, oregano, rosemary, lavender, fennel and laurel were carvacrol (37.9%), carvacrol (79.8), borneol (20.4%), camphor (20.2%), anethole (82.8%) and 1,8-cineole (35.5%), respectively. All essential oils were found to inhibit the growth of P. infestans in a dose-dependent manner. Volatile phase effect of oregano and thyme oils at 0.3 microg/ml air was found to completely inhibit the growth of P. infestans. Complete growth inhibition of pathogen by essential oil of fennel, rosemary, lavender and laurel was, however, observed at 0.4-2.0 microg/ml air concentrations. For the determination of the contact phase effects of the tested essential oils, oregano, thyme and fennel oils at 6.4 microg/ml were found to inhibit the growth of P. infestans completely. Essential oils of rosemary, lavender and laurel were inhibitory at relatively higher concentrations (12.8, 25.6, 51.2 microg/ml respectively). Volatile phase effects of essential oils were consistently found to be more effective on fungal growth than contact phase effect. Sporangial production was also inhibited by the essential oil tested. Light and scanning electron microscopic (SEM) observation on pathogen hyphae, exposed to both volatile and contact phase of oil, revealed considerable morphological alterations in hyphae such as cytoplasmic coagulation, vacuolations, hyphal shrivelling and protoplast leakage.
本研究的目的是找到一种替代合成杀菌剂的方法，目前合成杀菌剂用于防治毁灭性卵菌病原体致病疫霉，它是番茄晚疫病的病原体。研究了从牛至（叙利亚牛至变种贝瓦尼牛至）、百里香（穗花百里香亚种穗花百里香）、薰衣草（意大利薰衣草亚种意大利薰衣草）、迷迭香（迷迭香）、茴香（茴香）和月桂（月桂）等芳香植物地上部分提取的精油对致病疫霉的抗真菌活性。使用两种体外方法测定了不同浓度精油的接触相和挥发相效应。还通过气相色谱 - 质谱分析确定了精油的化学成分。在百里香、牛至、迷迭香、薰衣草、茴香和月桂的精油中发现的主要化合物分别是香芹酚（37.9%）、香芹酚（79.8%）、冰片（20.4%）、樟脑（20.2%）、茴香脑（82.8%）和1,8 - 桉叶素（35.5%）。发现所有精油均以剂量依赖性方式抑制致病疫霉的生长。发现牛至和百里香油在0.3微克/毫升空气的挥发相效应能完全抑制致病疫霉的生长。然而，在0.4 - 2.0微克/毫升空气浓度下观察到茴香、迷迭香、薰衣草和月桂的精油能完全抑制病原体的生长。为了测定受试精油的接触相效应，发现6.4微克/毫升的牛至、百里香和茴香油能完全抑制致病疫霉的生长。迷迭香、薰衣草和月桂的精油在相对较高浓度（分别为12.8、25.6、51.2微克/毫升）时具有抑制作用。始终发现精油的挥发相效应在抑制真菌生长方面比接触相效应更有效。所测试的精油也抑制了孢子囊的产生。对暴露于精油挥发相和接触相的病原体菌丝进行光学和扫描电子显微镜（SEM）观察，发现菌丝有相当大的形态改变，如细胞质凝聚、液泡化、菌丝萎缩和原生质体泄漏。
