Role of Volatile Organic Compounds in Plant Growth, Communication and Defense

Volatile organic compounds (VOCs) are chemical substances, which are produced and emitted by plants and other organisms in gaseous form. VOCs, which belong to various chemical classes, such as the terpenoids, the benzenoids and phenylpropanoids, fatty acid- derived molecules including the green leaf volatiles (GLVs) and minor classes such as nitriles and sulfides. VOCs help plants to germinate and help them to protect themselves against herbivore insects and parasites. Volatile organic compounds mediate the interaction between plants and mutualists, pests and pathogenic antagonists and also multi-trophic interactions. Bacterial volatiles play a significant role in promoting plant growth by regulating the synthesis or metabolism of phytohormones. This review is focused on the role of different VOCs in plant growth, their communication with other organisms as well as how they protect themselves by different environmental stress and threats.