ABSTRACT
Plants count on ecological services provided by pollinators or seed-dispersal animals through attracting them with volatile compounds from reproductive organs. On the other hand, volatiles from vegetative organs, such as leaves, stems, and roots, doesn’t seem to have the same function despite the organs have abilities to form, emit, and in some cases, accumulate volatiles. In most cases, vegetative plant volatiles are to defend against organisms that eat plants. Plants have acquired several sophisticated ways to make their ability to form volatiles effective against attackers.
This chapter gives updates of current knowledge of biosynthetic pathways for green leaf volatiles, volatile terpenes, and phenylpropanoid volatiles, in vegetative organs. The production of volatile compounds at the level sufficient for efficient defense requires appropriate transcriptional/posttranscriptional regulation of biosynthetic pathways and/or transport and deposition of final products on the accurate tissues/cells/subcellular compartments. The precise mechanism of regulation has become clear gradually but steadily. An array of findings about the mechanism obtained so far has significantly contributed to our understanding of evolution of the biosynthetic genes, tissue-localized production, and a glycosylated storage form for vegetative volatiles.
