Novel Acetylenic Oxylipins from the Moss Dicranum scoparium with Antifeeding Activity against Herbivorous Slugs
Novel Acetylenic Oxylipins from the Moss Dicranum scoparium with Antifeeding Activity against Herbivorous Slugs
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DOI：
10.1002/anie.201000825
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发表时间：
2010-01-01
影响因子：
16.6
通讯作者：
Pohnert, Georg
中科院分区：
文献类型：
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作者：
Rempt, Martin;Pohnert, Georg
即使在其他植物受到强烈食草动物压力的地区，苔藓也很少被取食。但即使在恩斯特·斯塔尔首次研究植物和苔藓对蛞蝓和蜗牛的化学防御100多年后[1]，我们对负责苔藓化学防御的代谢物的性质和生物合成仍知之甚少。[2，3] Dicranum scoparium是一种防御良好的苔藓;它在全球范围内分布在温带和北极森林中，经常出现在密集的斑块中，没有显示出食草动物的迹象。在最近的一项调查中，挥发性氧化脂（多不饱和脂肪酸氧化转化的产物）从苔藓，我们确定D。scoparium作为一个多产的生产者的这种代谢物。[4]此外，这种苔藓产生不寻常的炔属环戊烯酮从占主导地位的炔属脂肪酸dicranin大概也通过oxylipin途径。[5]受观察到氧化脂通常作为防御代谢产物或高等植物防御反应的调节剂的启发，[6，7]我们探索了D. scoparium。正如在高等植物和硅藻中观察到的那样，挥发性氧化脂的产生也是由苔藓中的机械损伤触发的。[6，8]比较从D.在组织破裂之前和之后的scoparium揭示了在创伤后数秒内产生代谢物的复杂混合物（图1）。由于色谱图的复杂性，我们的目标是解决由稳定同位素标记的生物合成前体指导的代谢途径。因此，我们制备了单和二氘代脂肪酸，并将其施用于苔藓（方案1）。
Mosses are seldom fed upon even in areas where intense herbivore pressure is observed on other plants. But even more than 100 years after the first investigations of Ernst Stahl on the chemical defense of plants and mosses against slugs and snails [1] we know very little about the nature and biosynthesis of metabolites responsible for moss chemical defense.[2, 3] Dicranum scoparium is an example of a well-defended moss; it is globally distributed in temperate and arctic forests and often occurs in dense patches that show no sign of herbivory. In a recent survey of the volatile oxylipins (products of the oxidative transformation of polyunsaturated fatty acids) from mosses, we identified D. scoparium as a prolific producer of such metabolites.[4] In addition, this moss produces unusual acetylenic cyclopentenones from the dominant acetylenic fatty acid dicranin presumably also by means of oxylipin pathways.[5]Motivated by the observation that oxylipins often serve as defense metabolites or regulators of defense reactions in higher plants,[6, 7] we explored the chemistry and chemical ecology of oxylipins of D. scoparium. As observed in higher plants and diatoms, the production of volatile oxylipins is triggered by mechanical wounding in mosses as well.[6, 8] Comparing the ultraperformance liquid chromatography/mass spectrometry (UPLC/MS) profiles of methanolic extracts obtained from D. scoparium before and after tissue disruption revealed that a complex mixture of metabolites is produced within seconds after wounding (Figure 1). Owing to the complexity of the chromatograms, we aimed to address the metabolic pathways guided by biosynthetic precursors labeled with stable isotopes. Therefore we prepared monoand dideuterated fatty acids and administered them to the moss (Scheme 1).