抄録
The ancestral cells of plants emerged about 1.5 billion years ago when primitive eukaryotic cells incorporated cyanobacteria. Since then, plants have developed an ever-maturing relationship with various microorganisms in the ecosystem. The competition for survival between plants and microorganisms has given rise to diverse relationships mediated by various compounds and that is thought to have been the driving force behind the diversification of plant and microorganism species. This article introduces three topics of plant-microbe interactions, which are either antagonistic or symbiotic relationships mediated by key substances.