Volatile terpenes – mediators of plant‐to‐plant communication

Abstract

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.

Characterization of VOCs Emitted by Foliage of Grapevine cv. Isabella for Prospecting Innovative Cropping Systems

“…Notably, Isabella leaves are characterized by the presence of dense trichomes [65] and cuticular waxes [66], which might have contributed as storage structures for terpene emissions, as reported in other species [67,68]. Terpenes play multiple roles in mediating antagonistic and beneficial interactions among organisms [69,70] and are involved in plant-to-plant communication and signaling [71].…”

The biochemical and molecular investigation of flower color and scent sheds lights on further genetic modification of ornamental traits in Clivia miniata

“…As the mainstay among most floral volatile organic compounds, volatile terpenes showed species-specificity with the possibility of great variations among related species [ 26 , 29 ]. It is widely accepted that floral terpenes function together with anthocyanins in the attraction of pollinators, dispersers and pest enemies, and biotic and abiotic resistances [ 6 , 69 ]. Compared with anthocyanins, floral terpenes seem to be more sensitive to environmental stimuli, or specific terpenes could only be detected in specific development stages [ 70 ], which was also validated in C. miniata as fewer terpenes and terpenes that were present in smaller quantities were detected when normally cultivated ( Fig.…”

“…On the other hand, hydrophobic carotenoids are responsible for colors ranging from yellow through orange to red and could be co-accumulated with anthocyanins [ 5 ]. A number of compounds with different origins, terpenes, benzenoids/phenylpropanoids, and fatty acid derivatives, especially terpenes with relatively small molecular weight (monoterpenes and sesquiterpenes), are volatile organic compounds responsible for the floral scent [ 6 , 7 ]. Those volatile organic compounds with relatively low odor thresholds perceived by people might play pivotal roles in flower fragrance [ 8 – 10 ].…”

Mycorrhiza-Tree-Herbivore Interactions: Alterations in Poplar Metabolome and Volatilome

“…On the other hand, the young, heavily infested leaves might rather invest in VOC-mediated defense and interactions. Volatile cues that function as intra-and interspecific signals are common responses of leaves to herbivore feeding [54]. In addition to being direct defense compounds, VOCs may help the trees to minimize losses by attracting herbivore enemies and by boosting the defenses in the adjacent, non-infested plant parts [55][56][57].…”