Green leaf volatile production by plants: a meta-analysis.

Contents Summary I. Introduction II. Biosynthesis III. Meta-analysis IV. The type of stress influences the total amount of GLVs released V. Herbivores can modulate the wound-induced release of GLVs VI. Fungal infection greatly induces GLV production VII. Monocots and eudicots respond differentially to different types of stress VIII. The type of stress does not influence the proportion of GLVs per chemical class IX. The type of stress does influence the isomeric ratio within each chemical class X. GLVs: from signal perception to signal transduction XI. GLVs influence C/N metabolism XII. Interaction with plant hormones XIII. General conclusions and unanswered questions Acknowledgements References SUMMARY: Plants respond to stress by releasing biogenic volatile organic compounds (BVOCs). Green leaf volatiles (GLVs), which are abundantly produced across the plant kingdom, comprise an important group within the BVOCs. They can repel or attract herbivores and their natural enemies; and they can induce plant defences or prime plants for enhanced defence against herbivores and pathogens and can have direct toxic effects on bacteria and fungi. Unlike other volatiles, GLVs are released almost instantly upon mechanical damage and (a)biotic stress and could thus function as an immediate and informative signal for many organisms in the plant's environment. We used a meta-analysis approach in which data from the literature on GLV production during biotic stress responses were compiled and interpreted. We identified that different types of attackers and feeding styles add a degree of complexity to the amount of emitted GLVs, compared with wounding alone. This meta-analysis illustrates that there is less variation in the GLV profile than we presumed, that pathogens induce more GLVs than insects and wounding, and that there are clear differences in GLV emission between monocots and dicots. Besides the meta-analysis, this review provides an update on recent insights into the perception and signalling of GLVs in plants.