Recognition of conserved microbial molecules activates immune responses in plants, a process termed pattern-triggered immunity (PTI). Similarly, insect eggs trigger defenses that impede egg development or attract predators, but information on the nature of egg-associated elicitors is scarce. We performed an unbiased bioactivity-guided fractionation of eggs of the butterfly Pieris brassicae. Nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry of active fractions led to the identification of phosphatidylcholines (PCs). PCs are released from insect eggs, and they induce salicylic acid and H2O2 accumulation, defense gene expression and cell death in Arabidopsis, all of which constitute a hallmark of PTI. Active PCs contain primarily C16 to C18-fatty acyl chains with various levels of desaturation, suggesting a relatively broad ligand specificity of cell-surface receptor(s). The finding of PCs as egg-associated molecular patterns (EAMPs) illustrates the acute ability of plants to detect conserved immunogenic patterns from their enemies, even from seemingly passive structures such as eggs.

中文翻译：

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来自芸苔属植物卵的磷脂酰胆碱激活拟南芥的免疫反应

识别保守的微生物分子会激活植物的免疫反应，这一过程称为模式触发免疫 (PTI)。类似地，昆虫卵会触发阻碍卵发育或吸引捕食者的防御，但关于与卵相关的诱导物性质的信息很少。我们对芸苔蝶的卵进行了无偏见的生物活性引导分馏。核磁共振 (NMR) 光谱和质谱的活性部分导致了磷脂酰胆碱 (PC) 的鉴定。PCs 是从昆虫卵中释放出来的，它们在拟南芥中诱导水杨酸和 H2O2 的积累、防御基因的表达和细胞死亡，所有这些都是 PTI 的标志。活性 PC 主要包含具有不同去饱和度的 C16 至 C18 脂肪酰基链，表明细胞表面受体具有相对广泛的配体特异性。PC 作为卵相关分子模式 (EAMP) 的发现说明了植物从敌人身上检测保守免疫原性模式的敏锐能力，即使是从看似被动的结构（如鸡蛋）。