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December 27, 2021


Volatile terpenes – mediators of plant-to-plant communication



plant-to-plant communication 植物間コミュニケーション



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.


VOC:Volatile Organic Compounds 揮発性有機化合物(VOCs)
sesquiterpenes セスキテルペン
plant–insect interactions植物-昆虫相互作用

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.


downstream signaling events 下流シグナル伝達
community 群落


Plants are known to detect their neighbors by various cues, such as ratios of red:far red light or ethylene in the air (Binder, 2020; Devlin, 2016). However, to not only detect, but also identify the neighbor, more detailed information is needed. Such information can be transmitted by volatile organic compounds (VOCs) both above- and belowground.


far red light 遠赤色光

Plants release a high diversity of various VOCs such as terpenes, fatty acid derivatives, amino acid derivatives, and phenylpropanoid/benzenoid compounds. Volatile terpenes are the most diverse group of VOCs comprising the C5 compound isoprene, C10 monoterpenes, C15 sesquiterpenes, and also C11 and C16 homoterpenes and some C20 diterpenes (Rosenkranz and Schnitzler, 2016).Terpenes can protect plants from various abiotic and biotic stresses (Loreto and Schnitzler, 2010; Unsicker et al., 2009).

植物はテルペン、脂肪酸誘導体、アミノ酸誘導体、フェニルプロパノイド/ベンゼノイド化合物などの様々な多様性高い揮発性有機化合物(VOCs)を放出します。揮発性テルペンは、C5化合物イソプレン、C10モノテルペン、C15セスキテルペン、およびC11およびC16ホモテルペンおよびいくつかのC20ディテルペン(Rosenkranz and Schnitzler, 2016).を含むVOCの最も多様なグループである。テルペンは、様々な非生物的および生物的ストレスから植物を保護することができます(Loreto and Schnitzler, 2010; Unsicker et al., 2009).

fatty acid derivatives,  脂肪酸誘導体  
amino acid derivatives, アミノ酸誘導体
abiotic 非生物的ストレス
biotic stresses 生物的ストレス

Moreover, they are important communication and interaction signals between plants and other organisms, including insects, fungi, and bacteria (Huang et al., 2003; Huang et al., 2012; Nieuwenhuizen et al., 2009; Schulz-Bohm et al., 2017). Different environmental constraints, such as herbivore feeding style (Simon et al., 2015), pathogen infection (Delaney et al., 2015), or belowground microbial communities (Kong et al., 2021), can induce very specific emission patterns from plants.

さらに、昆虫、真菌、細菌を含む植物と他の生物との間の重要なコミュニケーションおよび相互作用伝達シグナルである(Huang et al., 2003; Huang et al., 2012; Nieuwenhuizen et al., 2009; Schulz-Bohm et al., 2017). 異なる環境制約は、例えば、捕食者の摂食様式(Simon et al.、2015)、病原体感染(Delaney et al.、2015)、または地下の微生物群集(Kong et al., 2021),など、植物からの非常に特異的な放出パターンを誘導することができる。

herbivore 捕食者
microbial communities 微生物群集





December 20, 2021


Molecules. 2021 May; 26(9): 2571.

Smell and Stress Response in the Brain: Review of the Connection between Chemistry and Neuropharmacology





The stress response in the brain is not fully understood, although stress is one of the risk factors for developing mental disorders.On the other hand, the stimulation of the olfactory system can influence stress levels, and a certain smell has been empirically known to have a stress-suppressing effect, indeed. In this review, we first outline what stress is and previous studies on stress-responsive biomarkers (stress markers) in the brain. Subsequently, we confirm the olfactory system and review previous studies on the relationship between smell and stress response by species, such as humans, rats, and mice. Numerous studies demonstrated the stress-suppressing effects of aroma.


mental disorders 精神障害
a stress-suppressing effect ストレス抑制効果

There are also investigations showing the effects of odor that induce stress in experimental animals.

In addition, we introduce recent studies on the effects of aroma of coffee beans and essential oils, such as lavender, cypress, α-pinene, and thyme linalool on the behavior and the expression of stress marker candidates in the brain. The transfer of volatile components into the brain is also discussed while using the results of thyme linalool as an example. These studies may provide a good opportunity to connect chemical research at the molecular level with neuropharmacological approaches in the future.


Keywords: stress; smell; aroma; olfaction; brain; anxiety; fatigue; human; rat; mouse



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