Volatile isoprenoid emission potentials are correlated with essential isoprenoid concentrations in five plant species

This study offers new insight and data in support of the “opportunist hypothesis”. Five species of volatile isoprenoid-emitting plants (Eucalyptus globulus, Eucalyptus gunnii, Mucuna pruriens, Lycopersicon esculentum and Quercus ilex) were exposed to a wide range of imposed and natural stress conditions over a period of a few weeks in order to generate different levels of isoprenoid production potential. Volatile isoprenoid emissions and carotenoid concentrations were measured in all species and dimethylallyl diphosphate (DMAPP) concentrations were measured in E. globulus, E. gunnii, M. pruriens and L. esculentum. Generally, instantaneously emitted isoprenoid emissions were positively correlated with carotenoid concentrations, and were negatively correlated with DMAPP concentrations. In contrast, stored monoterpene emission potentials were negatively correlated with carotenoid concentrations, and positively correlated with DMAPP concentrations. These results support the possibility of a direct or indirect control of volatile isoprenoid emission potential via carotenoid synthesis at time scales of days to weeks.