Myung Kyung, Hamilton-Kemp Thomas R, Archbold Douglas D
Department of Horticulture, University of Kentucky, Lexington, Kentucky 40546-0091, USA.
J Agric Food Chem. 2007 Mar 21;55(6):2182-8. doi: 10.1021/jf0631629. Epub 2007 Feb 27.
The natural volatile compounds cis-3-hexenal (c-3-H) and trans-2-hexenal (t-2-H) have significant antifungal activity with potential for use as postharvest fumigants of fruits and vegetables. However, the nature of their interaction with fungi and impact on fungal growth at the molecular level are largely unknown. The sites of interaction of these six carbon (C6) aldehydes with Botrytis cinerea, a common pathogen of many plant species, was characterized using 3H-labeled c-3-H and t-2-H. Radiolabeled C6 aldehydes were produced with lipoxygenase and hydroperoxide lyase extracts using [9,10,12,13,15,16-3H6]linolenic acid as a substrate. Following exposure of B. cinerea cultures to radiolabeled C6 aldehydes, radiolabel was recovered in protein-enriched but not lipid-enriched fractions. Radiolabel was incorporated at higher levels (6-fold per milligram of fresh weight and 4-fold per microgram of protein) into conidia than mycelia. About 95% of the radiolabeled aldehyde recovered in the protein fraction was from the surface of the fungal tissue, while 5% was from protein in internal tissue (cell wall, membrane, and cytosol). Exposure to t-2-H at both 5.4 and 85.6 micromol affected the protein profile of B. cinerea, changing the intensity of over one-third of all proteins. Both up-regulation and down-regulation of specific proteins were observed by two-dimensional gel electrophoresis, indicating a clear effect of t-2-H on changes in the protein profile of B. cinerea. This is the first evidence that fungal proteins are targets of the volatile C6 aldehydes and that sublethal levels of the aldehydes cause changes in the protein profile of a fungus.
天然挥发性化合物顺式-3-己烯醛（c-3-H）和反式-2-己烯醛（t-2-H）具有显著的抗真菌活性，有潜力用作水果和蔬菜的采后熏蒸剂。然而，它们与真菌相互作用的性质以及在分子水平上对真菌生长的影响在很大程度上尚不清楚。使用3H标记的c-3-H和t-2-H对这些六碳（C6）醛与许多植物物种的常见病原体灰葡萄孢的相互作用位点进行了表征。以[9,10,12,13,15,16-3H6]亚麻酸为底物，用脂氧合酶和氢过氧化物裂解酶提取物制备放射性标记的C6醛。将灰葡萄孢培养物暴露于放射性标记的C6醛后，在富含蛋白质而非富含脂质的组分中回收了放射性标记。放射性标记在分生孢子中的掺入水平（每毫克鲜重6倍，每微克蛋白质4倍）高于菌丝体。在蛋白质组分中回收的放射性标记醛约95%来自真菌组织表面，5%来自内部组织（细胞壁、膜和细胞质）中的蛋白质。在5.4和85.6微摩尔浓度下暴露于t-2-H均会影响灰葡萄孢的蛋白质谱，改变了超过三分之一的所有蛋白质的强度。通过二维凝胶电泳观察到特定蛋白质的上调和下调，表明t-2-H对灰葡萄孢蛋白质谱的变化有明显影响。这是第一个证据表明真菌蛋白质是挥发性C6醛的靶标，并且醛的亚致死水平会导致真菌蛋白质谱的变化。
