Language of plants: Where is the word?

Abstract

Plants emit biogenic volatile organic compounds (BVOCs) causing transcriptomic, metabolomic and behavioral responses in receiver organisms. Volatiles involved in such responses are often called "plant language". Arthropods having sensitive chemoreceptors can recognize language released by plants. Insect herbivores, pollinators and natural enemies respond to composition of volatiles from plants with specialized receptors responding to different types of compounds. In contrast, the mechanism of how plants "hear" volatiles has remained obscured. In a plant-plant communication, several individually emitted compounds are known to prime defense response in receiver plants with a specific manner according to the chemical structure of each volatile compound. Further, composition and ratio of volatile compounds in the plant-released plume is important in plantinsect and plant-plant interactions mediated by plant volatiles. Studies on volatile-mediated plant-plant signaling indicate that the signaling distances are rather short, usually not longer than one meter. Volatile communication from plants to insects such as pollinators could be across distances of hundreds of meters. As many of the herbivore induced VOCs have rather short atmospheric life times, we suggest that in long-distant communications with plant volatiles, reaction products in the original emitted compounds may have additional information value of the distance to emission source together with the original plant-emitted compounds.

Microbe‐induced plant volatiles

“…Volatiles can act as airborne signals in plant-plant interactions at a distance of < 1 m or as below-ground signals at a distance of 15-30 cm (Simpraga et al, 2016;Arimura & Pearse, 2017). These observations could be used to develop management strategies for plant pests and diseases by intercropping and cultivar mixing.…”

“…The total biomes of plants and microbes were recently recognized as 'holobiomes', which have been codeveloping for a long period of time. Volatiles act as a universal language in this interaction (Mith€ ofer & Boland, 2016;Simpraga et al, 2016). In addition to MIPVs, the adaptation of plant physiological responses to microbial volatiles represents the next important topic to investigate.…”

“…In addition, plants obtain information about their invaders even before direct contact using volatiles as infochemicals (Baldwin et al, 2006;Quintana-Rodriguez et al, 2015). Volatiles symbolize the chemical language of plants, which they use to communicate with other plants and even other members of the phytobiome, such as insects, nematodes and microbes (bacteria, fungi and viruses) (Ali et al, 2012;Pangesti et al, 2016;Simpraga et al, 2016).…”

“…Researchers later found that injured plants emit specific and de novo blends of volatiles that are received by neighboring plants or distant parts of the same plant (Baldwin & Schultz, 1983;Frost et al, 2007). These volatiles include green leaf volatiles (GLVs; C6 fatty acid derivatives from the oxylipin pathway), isoprenoids (terpenes) from the mevalonate or methylerythritol phosphate pathways, and metabolites from the shikimic acid pathway, such as methyl salicylate (MeSA) and indole (Simpraga et al, 2016). These compounds were initially known as herbivore-induced plant volatiles (HIPVs) because plants release them immediately after attack by chewing or sucking insects.…”

Plant biotic interactions

“…Besides proteins and RNAs, volatile organic compounds emitted by plants also serve as important signals for communication between plants and interacting insects and pests. Simpraga and colleagues () highlighted the discoveries on perception and signaling in insects, such as herbivores, in response to such “plant volatile language”. In addition, Drs.…”