Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland.
J Exp Bot. 2023 Feb 13;74(4):1207-1220. doi: 10.1093/jxb/erac449.
When attacked by herbivores, plants produce electrical signals which can activate the synthesis of the defense mediator jasmonate. These wound-induced membrane potential changes can occur in response to elicitors that are released from damaged plant cells. We list plant-derived elicitors of membrane depolarization. These compounds include the amino acid l-glutamate (Glu), a potential ligand for GLUTAMATE RECEPTOR-LIKE (GLR) proteins that play roles in herbivore-activated electrical signaling. How are membrane depolarization elicitors dispersed in wounded plants? In analogy with widespread turgor-driven cell and organ movements, we propose osmoelectric siphon mechanisms for elicitor transport. These mechanisms are based on membrane depolarization leading to cell water shedding into the apoplast followed by membrane repolarization and water uptake. We discuss two related mechanisms likely to occur in response to small wounds and large wounds that trigger leaf-to-leaf electrical signal propagation. To reduce jasmonate pathway activation, a feeding insect must cut through tissues cleanly. If their mandibles become worn, the herbivore is converted into a robust plant defense activator. Our models may therefore help to explain why numerous plants produce abrasives which can blunt herbivore mouthparts. Finally, if verified, the models we propose may be generalizable for cell to cell transport of water and pathogen-derived regulators.
当受到食草动物攻击时，植物会产生电信号，从而激活防御介质茉莉酸的合成。这些由伤口引起的膜电位变化可以响应从受损植物细胞释放的激发子而发生。我们列出了植物来源的去极化激发子。这些化合物包括氨基酸 l-谷氨酸（Glu），它是 GLUTAMATE RECEPTOR-LIKE（GLR）蛋白的潜在配体，在食草动物激活的电信号中发挥作用。在受伤的植物中，膜去极化激发子是如何分散的？与广泛的膨压驱动的细胞和器官运动类似，我们提出了用于激发子运输的渗透电渗流机制。这些机制基于膜去极化导致细胞水排入质外体，随后膜再极化和水吸收。我们讨论了两种相关的机制，这两种机制可能会响应小伤口和大伤口而发生，从而触发叶片间的电信号传播。为了减少茉莉酸途径的激活，取食昆虫必须干净利落地切割组织。如果它们的下颚变钝，食草动物就会变成强大的植物防御激活剂。因此，我们的模型可能有助于解释为什么许多植物会产生磨料，从而可以钝化食草动物的口器。最后，如果得到验证，我们提出的模型可能适用于水和病原体衍生调节剂的细胞间运输。
