Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology, Helmholtz Zentrum Muenchen, 85764, Neuherberg, Germany.
Institute of Biochemical Plant Pathology, Helmholtz Zentrum Muenchen, 85764, Neuherberg, Germany.
Plant J. 2021 Nov;108(3):617-631. doi: 10.1111/tpj.15453. Epub 2021 Aug 28.
Plants interact with other organisms employing volatile organic compounds (VOCs). The largest group of plant-released VOCs are terpenes, comprised of isoprene, monoterpenes, and sesquiterpenes. Mono- and sesquiterpenes are well-known communication compounds in plant-insect interactions, whereas the smallest, most commonly emitted terpene, isoprene, is rather assigned a function in combating abiotic stresses. Recently, it has become evident that different volatile terpenes also act as plant-to-plant signaling cues. Upon being perceived, specific volatile terpenes can sensitize distinct signaling pathways in receiver plant cells, which in turn trigger plant innate immune responses. This vastly extends the range of action of volatile terpenes, which not only protect plants from various biotic and abiotic stresses, but also convey information about environmental constraints within and between plants. As a result, plant-insect and plant-pathogen interactions, which are believed to influence each other through phytohormone crosstalk, are likely equally sensitive to reciprocal regulation via volatile terpene cues. Here, we review the current knowledge of terpenes as volatile semiochemicals and discuss why and how volatile terpenes make good signaling cues. We discuss how volatile terpenes may be perceived by plants, what are possible downstream signaling events in receiver plants, and how responses to different terpene cues might interact to orchestrate the net plant response to multiple stresses. Finally, we discuss how the signal can be further transmitted to the community level leading to a mutually beneficial community-scale response or distinct signaling with near kin.
植物通过挥发性有机化合物（VOCs）与其他生物相互作用。植物释放的最大 VOC 群是萜类化合物，包括异戊二烯、单萜和倍半萜。单萜和倍半萜是植物与昆虫相互作用中众所周知的通讯化合物，而最小、最常释放的萜类化合物异戊二烯，则被认为在抵御非生物胁迫方面具有功能。最近，人们已经意识到，不同的挥发性萜类化合物也可以作为植物间的信号传递线索。当被感知到时，特定的挥发性萜类化合物可以使接收植物细胞中的特定信号通路敏感化，进而触发植物先天免疫反应。这极大地扩展了挥发性萜类化合物的作用范围，它们不仅保护植物免受各种生物和非生物胁迫的影响，还传递了植物内部和之间环境限制的信息。因此，植物-昆虫和植物-病原体的相互作用，被认为通过植物激素的串扰相互影响，可能同样容易受到挥发性萜类化合物信号的相互调节。在这里，我们回顾了萜类化合物作为挥发性信息素的现有知识，并讨论了为什么以及如何挥发性萜类化合物可以作为良好的信号传递线索。我们讨论了植物如何感知挥发性萜类化合物，接收植物中可能的下游信号事件，以及不同萜类化合物线索的反应如何相互作用，以协调植物对多种胁迫的综合反应。最后，我们讨论了信号如何进一步传递到群落水平，导致互利的群落尺度反应或与近亲的不同信号。
