Plants use volatile organic compounds (VOCs) as vital signals to communicate with each other and other organisms when facing attacks from herbivorous pests. This review delves into how this plant communication works and its potential for sustainable agriculture. The research highlights the benefits of combining VOC-based methods with companion planting and biostimulants to improve pest management strategies. This innovative approach could lessen the dependency on harmful agricultural chemicals, facilitating eco-friendly farming techniques aimed at plant protection and higher yields.
Volatile organic compounds (VOCs) are crucial airborne signals that enable plants to convey messages to other organisms and plants, both nearby and far away. A significant part of this communication occurs when a plant is harmed by herbivores, which leads to the release of VOCs. Nearby plants can detect these compounds and, in response, enhance their defensive mechanisms against possible threats. This intricate biochemical strategy allows plants to effectively shield themselves from various stress factors.
Recently, this area of research has attracted considerable attention due to its potential agricultural applications. Professors Gen-ichiro Arimura and his colleague Mr. Takuya Uemura from Tokyo University of Science, Japan, investigated the molecular pathways involved in this plant communication and its implications for sustainable agricultural practices.
Their review, published online on October 11, 2024, in Trends in Plant Science, highlights these complex processes and their significance for agricultural progress. The study investigated how insights into plant-to-plant communication could inspire innovative methods for crop protection and yield enhancement, possibly transforming sustainable agriculture.
“Although plants lack the sophisticated olfactory systems of animals, they can still detect and react to a broad range of VOCs based on their structural similarities to compounds encountered during past beneficial or harmful interactions,” states Prof. Arimura.
When faced with attacks, plants release different types of VOCs, including isoprene, terpenoids, and green leaf volatiles. These compounds are known for their role in interspecies signaling, luring beneficial insects, or deterring herbivores. Particularly, monoterpenoids found abundantly in mint plants are valued for their properties of repelling pests, fighting microbes, and killing eggs. The research shows that plant interactions involving VOCs are not exclusive to related species but can occur among unrelated plants as well.
Once released, VOCs are taken in through stomata and spread across the mesophyll cells of neighboring plants. The response of these plants is governed by complex signaling pathways, including calcium fluxes that are integral to the signaling cascades. For example, hydrocarbons such as β-caryophyllene can influence gene expression in receiving plants by interacting with chromatin, the structure regulating DNA accessibility. This chromatin remodeling process activates gene transcription, preparing the plant for improved defense mechanisms.
Today, many farmers use chemical pesticides for crop protection; however, their negative impact on the environment, combined with the increasing need for greater food production, highlights the urgency for safer alternatives. Utilizing VOCs presents a sustainable solution that boosts crop defense while enhancing productivity and reducing dependence on harmful pesticides and chemicals. Furthermore, this approach could lower production costs and enhance the quality of produce, as many consumers prefer ‘pesticide-free crops’ for their health.
“One effective strategy is to incorporate companion plants such as potted mint, candy mint, and pepper mint, which consistently release beneficial VOCs. Additionally, creating biostimulants—agents that improve plant growth and resilience—could further strengthen plant interactions,” notes Prof. Arimura. He also mentions that new commercial products based on these findings will soon become available for agricultural use.
However, applying VOC-focused technologies in agriculture presents challenges, including varying responses based on dosage and difficulties related to the spacing of plants and the concentration of VOCs (allelochemicals), which might inhibit the growth of neighboring plants.
In conclusion, this review encourages further investigation into the role of VOCs in agriculture and calls on the scientific community to partner with farmers and policymakers to tap into the advantages of plant communication. By utilizing the natural signaling processes of plants, we can create sustainable farming methods that not only enhance crop productivity but also support environmental health.
