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The timing of plant volatile emissions is important for a robust indirect defense response. Green leaf volatiles (GLVs) are emitted by plants upon damage but can be suppressed by herbivore‐associated elicitors, and the abundance and composition of GLVs vary depending on the timing of herbivore attack. We show that the GLV biosynthetic enzyme HYDROPEROXIDE LYASE (HPL) is transcriptionally regulated by the circadian clock in Nicotiana attenuata. In accordance with transcript abundance of NaHPL, GLV aldehyde pools in intact leaves peaked at night and at subjective night under diurnal and continuous light conditions, respectively. Moreover, although the basal abundance of NaHPL transcripts is upregulated by jasmonate (JA) signaling, JA does not regulate the reduction of NaHPL transcript abundance in damaged leaves by simulated herbivore treatment. Unexpectedly, the plant circadian clock was strongly altered when Manduca sexta larvae fed on N. attenuata, and this was also independent of JA signaling. Lastly, the temporal dynamics of NaHPL transcripts and total GLV emissions were strongly altered by M. sexta larval feeding. Our data suggest that the temporal dynamics of emitted GLV blends result from a combination of damage, JA signaling, herbivore‐associated elicitors, and the plant circadian clock. Herbivore‐induced plant volatiles display complex temporal dynamics, which matter for effectively attracting the natural enemies of herbivores. Here, we show that green leaf volatile (GLV) biosynthesis in the wild tobacco Nicotiana attenuata has a circadian rhythm. Interestingly, although the biosynthesis of GLVs is jasmonate‐dependent, herbivore elicitors suppress GLV biosynthesis. Moreover, herbivory strongly alters the diurnal rhythm of circadian clock gene transcript levels: the effect of herbivory differs depending on the elicitors used and treatment time. This study reveals how a plant shapes its temporal dynamics of GLVs emissions by integrating circadian clock signaling with herbivore‐induced responses. [ABSTRACT FROM AUTHOR]

Summary: Plants emit a plethora of volatile organic compounds in response to biotic and abiotic stresses. These compounds act as infochemicals for ecological communication in the phytobiome. This study reviews the role of microbe‐induced plant volatiles (MIPVs) in plant–microbe interactions. MIPVs are affected by the taxonomic position of the microbe, the identity of the plant and the type of interaction. Plants also emit exclusive blends of volatiles in response to nonhost and host interactions, as well as to beneficial microbes and necrotrophic/biotrophic pathogens. These MIPVs directly inhibit pathogen growth and indirectly promote resistance/susceptibility to subsequent plant pathogen attack. Viruses and phloem‐limiting bacteria modify plant volatiles to attract insect vectors. Susceptible plants can respond to MIPVs from resistant plants and become resistant. Recent advances in our understanding of the molecular mechanisms of MIPV synthesis in plants and how plant pathogen effectors manipulate their biosynthesis are discussed. This knowledge will help broaden our understanding of plant–microbe interactions and should facilitate the development of new emerging techniques for sustainable plant disease management. See also the Editorial by Kessler, 220: 655–658. [ABSTRACT FROM AUTHOR]