More than 12,000 plant species (ca. 10% of flowering plants) exude latex when their tissues are injured. Latex is produced and stored in specialized cells named “laticifers”. Laticifers form a tubing system composed of rows of elongated cells that branch and create an internal network encompassing the entire plant. Laticifers constitute a recent evolutionary achievement in ecophysiological adaptation to specific natural environments; however, their fitness benefit to the plant still remains to be proven. The identification of Euphorbia lathyris mutants (pil mutants) deficient in laticifer cells or latex metabolism, and therefore compromised in latex production, allowed us to test the importance of laticifers in pest resistance. We provided genetic evidence indicating that laticifers represent a cellular adaptation for an essential defense strategy to fend off arthropod herbivores with different feeding habits, such as Spodoptera exigua and Tetranychus urticae. In marked contrast, we also discovered that a lack of laticifer cells causes complete resistance to the fungal pathogen Botrytis cinerea. Thereafter, a latex-derived factor required for conidia germination on the leaf surface was identified. This factor promoted disease susceptibility enhancement even in the non-latex-bearing plant Arabidopsis. We speculate on the role of laticifers in the co-evolutionary arms race between plants and their enemies.

超过 12,000 种植物（约占开花植物的 10%）在其组织受伤时会分泌乳胶。乳胶是在称为“乳胶管”的特殊细胞中产生和储存的。乳管形成一个由成排细长细胞组成的管道系统，这些细长细胞分支并形成包围整个植物的内部网络。乳管是适应特定自然环境的生态生理学的最新进化成果；然而，它们对植物的健康益处仍有待证实。大戟突变体（ pil突变体）的鉴定缺乏乳汁细胞或乳胶代谢，因此乳胶生产受到影响，使我们能够测试乳管在害虫抗性中的重要性。我们提供的遗传证据表明，乳管代表了一种基本防御策略的细胞适应，以抵御具有不同食性的节肢动物食草动物，例如甜菜夜蛾和二斑叶螨。与此形成鲜明对比的是，我们还发现，缺乏乳管细胞会导致对真菌病原体灰葡萄孢的完全抵抗。此后，鉴定了分生孢子在叶表面萌发所需的乳胶衍生因子。即使在非乳胶植物拟南芥中，该因素也促进了疾病易感性的增强。我们推测乳管在植物与其敌人之间的共同进化军备竞赛中的作用。