Phytotoxic α-pyrones produced by Pestalotiopsis guepinii, the causal agent of hazelnut twig blight
Phytotoxic α-pyrones produced by Pestalotiopsis guepinii, the causal agent of hazelnut twig blight
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DOI：
10.1038/ja.2011.134
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发表时间：
2012-04-01
影响因子：
3.3
通讯作者：
Vurro, Maurizio
中科院分区：
文献类型：
--
作者：
Evidente, Antonio;Zonno, Maria Chiara;Vurro, Maurizio
Guepinii拟盘多毛孢（Desm.）是榛子（Corylus avellana L.）这是造成产量损失的主要原因之一。Guepinii也已从胡桃（Juglans spp.）和乳香树（Pistacia lentiscus var. Chia）。最近，通过光谱方法分离并鉴定了由P. guepinii在体外培养物中产生的主要亲脂性植物毒性代谢物为pestalopyrone（7），1一种已知为由Pestalotiopsis oenotherae产生的次要毒素的pentaketide。2当真菌在不同的培养基上生长时，3通过纯化培养滤液获得的不含培他吡喃酮的部分被证明是植物毒性的。进一步纯化得到另外两种无定形的植物毒性代谢产物（1和6，图1），通过初步的光谱实验（包括~ 1H和~（13）C NMR、IR和UV）显示与α-吡喃酮密切相关。（1-羟基戊基）-4-甲氧基-吡喃-2-酮的旋光度、IR、UV、1H和13 C NMR谱与文献中报道的从青霉4中分离的代谢产物PC-2非常相似，5同样的a-吡喃酮（1）也与（-）-没食子酸内酯及其生物前体一起从Galiellarufa中相继分离。6诺地青霉、奥氏青霉和疣状青霉7以及最近发现的一种海洋来源的炭角菌PSU-F100 8也显示出产生1。1的结构得到COSY、HSQC和HMBC光谱（表1）中观察到的数据以及ESIMS数据的支持。除了二聚体和毒素本身的钠簇以及在m/z 447 [2XM+ Na]+、235 [M+ Na]+、213 [M+ H]+处观察到的假分子离子之外，ESIMS光谱还显示了在m/z 191处的显著的碎片峰[M+ Na-CO2]+，其是由钠簇通过CO2损失产生的碎片
Pestalotiopsis guepinii (Desm.) is the fungal causal agent of the so-called ‘twig blight’, one of the most serious diseases of hazelnut (Corylus avellana L.) in Turkey, and one of the main causes of yield losses. P. guepinii has been also isolated from walnut (Juglans spp.) and gum mastic tree (Pistacia lentiscus var. Chia). Recently, the main lipophilic phytotoxic metabolite produced by P. guepinii in vitro culture was isolated and identified by spectroscopic methods as pestalopyrone (7), 1 a pentaketide already known as a minor toxin produced by Pestalotiopsis oenotherae. 2 When the fungus was grown on a different culture medium, 3 some fractions obtained by the purification of the culture filtrate, not containing pestalopyrone, proved to be phytotoxic. Their further purification yielded other two amorphous phytotoxic metabolites (1 and 6, Figure 1) that by preliminary spectroscopic experiments (including 1H and 13C NMR, IR and UV) appeared to be closely related to a-pyrones.Indeed 1 was identified as 6-(1-hydroxypentyl)-4-methoxy-pyran-2-one and showed optical rotation, IR, UV, 1H and 13C NMR spectra very similar to those previously reported in literature for the metabolite named PC-2 isolated from a Penicillium sp. 4, 5 The same a-pyrone (1) was successively isolated also from Galiella rufa together with (-)-gallielactone and its biogenetic precursor. 6 Penicillium nordicum, P. olsonii and P. verrucosum 7 and recently a marine-derived fungus Xylaria sp. PSU-F100 8 also showed to produce 1. The structure assigned to 1 was supported by the data observed in its COSY, HSQC and HMBC spectra (Table 1) as well as also by the data of the ESIMS. Beside both sodium clusters of the dimmer and the toxin itself, and the pseudomolecular ion observed at m/z 447 [2XM+ Na]+, 235 [M+ Na]+, 213 [M+ H]+, the ESIMS spectrum also showed the significant fragmentation peak [M+ Na-CO2]+ at m/z 191 generated from the sodium cluster by loss of CO2, which is a fragmentation