MOLECULAR MECHANISMS INVOLVED IN CHEMICAL COMMUNICATION BETWEEN PLANTS

当被食草动物侵染时，植物释放出特定的挥发物混合物，吸引食草动物的食肉天敌。这些挥发物可以作为被侵染植物的求救信号。因此，草食诱导挥发物的排放可以被认为是“植物对草食动物的诱导-间接防御”。在本研究中，我们扩展了诱导-间接防御的概念，提出了“间接互作网”的新概念，即植物性状的定性和/或定量变化增强了由植物、草食和肉食性节肢动物组成的营养系统中相互作用网络的多样性。这一观点为阐明植物与植物之间的相互作用在生态系统中的作用提供了新的途径。我们还研究了草食诱导植物挥发物介导植物-植物相互作用的机制。我们建立了一种利用equorin蛋白分析植物与植物相互作用的分子机制的新方法。我们发现，青豆叶片暴露于草食诱导的植物挥发物后，通过吸附过程释放出挥发物。此外，我们还发现，暴露于草食诱导植物挥发物的叶片在受到荨麻蚜侵害时，比暴露于未检测叶片挥发物的叶片释放出更多的草食诱导植物挥发物。因此，我们得出结论，挥发物的吸附和产生都可以介导肉食性螨对暴露于受感染邻居挥发物的植物的吸引力。此外，作为新的观点，我们发现(1)植物暴露于草食诱导的植物挥发物后诱导了花外花蜜，(2)暴露于草食诱导的植物挥发物导致了根和三分体的形成。我们还建立了数学模型来验证植物-植物相互作用是对挥发性接收植物的适应性假设。

When infested by herbivores, plants emit specific blend of volatiles that attract carnivorous natural enemies of herbivores. Such volatiles can be SOS signal of infested plants. Thus, the emission of herbivore-induced volatiles can be considered to be "induced-indirect defense of plants against herbivores". In this study, we extended the idea of induced-indirect defense, and proposed new idea of ""indirect-interaction webs" in which qualitative and/or quantitative changes in plant traits enhance the diversity of interaction networks in tritrophic systems consisting of plants, herbivorous and carnivorous arthropods. This idea shows new approaches clarifying the role of plant-plant interactions in ecosystems. We also investigated the mechanisms involved in the plant-plant interactions mediated by herbivore-induced plant volatiles. We established a new methods using equorin protein to analyze the molecular mechanisms involved in plant-plant interactions. We found that that lima bean leaves emitted volatiles through the adsorption process after the exposure to herbivore-induced plant volatiles. In addition, we also found that herbivore-induced plant volatiles-exposed leaves emitted larger amounts of herbivore-induced plant volatiles in response to the infestation by T. urticae than leaves exposed to unifested leaf volatiles. We therefore conclude that both adsorption and production of volatiles can mediate the attraction of carnivorous mites to plants that have been exposed to volatiles from infested neighbors. Further, as new viewpoints, we found that (1)extra-floral nectar was induced in plants in response to the exposure of herbivore-induced plant volatiles, and (2)the exposure of herbivore-induced plant volatiles resulted in the root and tricome formation. We also made mathematical models to test the hypothesis that plant-plant interaction is the adaptive to the volatile receiving plants.