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The original version of this article unfortunately contained a mistake. Under the heading "Insects" in "Methods and Materials" the sentence "A colony of N. viridula originated with field collections near Tifton, Georgia, USA" is incorrect.

Insects use a wide range of structurally diverse pheromones for intra-specific communication. Compounds in the class of terpenes are emitted as sex, aggregation, alarm, or trail pheromones. Despite the common occurrence of terpene pheromones in different insect lineages, their origin from dietary host plant precursors or de novo biosynthetic pathways often remains unknown. Several stink bugs (Hemiptera: Pentatomidae) release bisabolene-type sesquiterpenes for aggregation and mating. Here we provide evidence for de novo biosynthesis of the sex pheromone trans−/cis-(Z)-α-bisabolene epoxide of the Southern green stink bug, Nezara viridula. We show that an enzyme (NvTPS) related to isoprenyl diphosphate synthases (IDSs) of the core terpene metabolic pathway functions as a terpene synthase (TPS), which converts the general intermediate (E,E)-farnesyl diphosphate (FPP) to the putative pheromone precursor (+)-(S,Z)-α-bisabolene in vitro and in protein lysates. A second identified IDS-type protein (NvFPPS) makes the TPS substrate (E,E)-FPP and functions as a bona fide FPP synthase. NvTPS is highly expressed in male epidermal tissue associated with the cuticle of ventral sternites, which is in agreement with the male specific release of the pheromone from glandular cells in this tissue. Our study supports findings of the function of similar TPS enzymes in the biosynthesis of aggregation pheromones from the pine engraver beetle Ips pini, the striped flea beetle Phyllotreta striolata, and the harlequin bug Murgantia histrionica, and hence provides growing evidence for the evolution of terpene de novo biosynthesis by IDS-type TPS families in insects.

Microorganisms colonize the surfaces of plant roots, leaves, and flowers known as the rhizosphere, phyllosphere, and anthosphere. These spheres differ largely in a number of factors that may determine the ability of microbes to establish themselves and to grow in these habitats. In this article, we focus on volatile organic compounds (VOCs) emitted by plants, and we discuss their effects on microbial colonizers, with an emphasis on bacteria. We present examples of how growth-inhibiting properties and mechanisms of VOCs such as terpenoids, benzenoid compounds, aliphatics, and sulfur containing compounds prevent bacterial colonization at different spheres, in antagonism with their role as carbon-sources that support the growth of different bacterial taxa. The notion that VOCs represent important factors that define bacterial niches is further supported by results for representatives of two bacterial genera that occupy strongly diverging niches based on scent emissions of different plant species and organs. Bacteria are known to either positively or negatively affect plant fitness and to interfere with plant-animal interactions. Thus, bacteria and other microbes may select for VOCs, enabling plants to control microbial colonizers on their surfaces, thereby promoting the growth of mutualists and preventing the establishment of detrimental microbes.