Mahoney Noreen, Molyneux Russell J, Smith Leverett R, Schoch Thomas K, Rolshausen Philippe E, Gubler W Douglas
Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 800 Buchanan Street, Albany, California 94710, USA.
J Agric Food Chem. 2005 Oct 19;53(21):8148-55. doi: 10.1021/jf0510236.
Dying-arm disease in grapevines, produced by infection with the ascomycete Eutypa lata, is responsible for major production losses in vineyards. Dieback of the shoots and cordon is believed to be due to acetylenic phenol metabolites produced by the fungus. To identify specific metabolites that could potentially be used for diagnosis of infection, eight E. lata isolates were grown in vitro on hot water extracts from grape varieties with various degrees of tolerance to the foliar symptoms of E. lata dieback. HPLC analysis showed that eutypinol was consistently produced in large amounts, together with smaller amounts of methyleutypinol and eulatachromene; eutypine, the putative toxin, was produced solely on Sauvignon Blanc extract and then in only barely detectable amounts. When E. lata isolates from Cabernet Sauvignon and Merlot were grown on identical media, the amounts of metabolites produced differed significantly between isolates but the pattern of metabolites was quite similar, with eutypinol again predominating. The consistent production of eutypinol indicated that this was the most suitable metabolite for which to analyze in order to diagnose the presence of E. lata. Extraction and analysis of grapevine tissues exhibiting symptoms of dieback failed to show the presence of any metabolites. However, when infected cordon sections were placed in water and cultured for 5 days, eutypinol was readily detected in the aqueous solution; metabolites were not produced from uninfected tissue. This provides a method for detection of infected tissue and indicates that the toxic metabolites react at the point of production, disrupting the vascular structure and inhibiting transport of nutrients, rather than being translocated to tissues that exhibit symptoms.
葡萄藤的死臂病由子囊菌 Eutypa lata 感染引起，会给葡萄园造成重大产量损失。嫩梢和主蔓的枯死据信是由该真菌产生的炔酚代谢产物所致。为了鉴定可能用于诊断感染的特定代谢产物，将 8 株 E. lata 分离株在体外培养于来自对 E. lata 死臂病叶部症状具有不同耐受程度的葡萄品种的热水提取物上。高效液相色谱分析表明，eutypinol 始终大量产生，同时还有少量的甲基 eutypinol 和 eulatachromene；推定的毒素 eutypine 仅在长相思提取物上产生，且产量仅勉强可检测到。当来自赤霞珠和梅洛的 E. lata 分离株在相同培养基上生长时，不同分离株产生的代谢产物量存在显著差异，但代谢产物模式非常相似，eutypinol 再次占主导地位。eutypinol 的持续产生表明，这是用于分析以诊断 E. lata 存在的最合适代谢产物。对表现出枯死症状的葡萄藤组织进行提取和分析，未发现任何代谢产物。然而，当将受感染的主蔓切段置于水中培养 5 天时，在水溶液中很容易检测到 eutypinol；未感染的组织未产生代谢产物。这提供了一种检测受感染组织的方法，并表明有毒代谢产物在产生点起作用，破坏维管结构并抑制养分运输，而不是转移到表现出症状的组织中。
