The Role of Root-Produced Volatile Secondary Metabolites in Mediating Soil Interactions

Since Darwin’s suggestion that natural selection accounts for the diversity of plant morphological and chemical attributes, thousands of papers have been devoted to the ecology and evolution of plant secondary metabolites. Indeed, it is estimated that plants may produce over 200, 000 different compounds, the majority of which are classified as secondary metabolites (Pichersky and Gang 2000). The incredible diversity of particular classes of secondary metabolites is stunning. Terpenes, for example, comprise more than 30’000 described compounds (Hartmann 2007). Such incredible diversity of forms can be originated from various enzymes catalyzing the binding of different precursors (Wojciechowski 2003), promiscuity of enzymes (including multiple product and substrate enzyme specificity), changes in cellular compartmentalization patterns (Pichersky and Gang 2000; Bauer et al. 2010), or the matrix-like structure of pathways where natural products are formed by elaborate arrays of enzymes, concertedly controlled by the expression of their respective genes (Lewinsohn and Gijzen 2009).