A genetically mosaic Eucalyptus tree is able to control which leaves are saved from predation because of alterations in its genes, according to Amanda Padovan of the Foley Lab at the ANU Research School of Biology.
Long-lived trees can somatic accumulate mutations throughout their lifetimes that may influence biotic and abiotic interactions. For example, some Eucalyptus trees display marked variation in herbivore defence within a single canopy. These 'mosaic' trees support foliage with distinct chemotypes which are differentially favoured by insect and vertebrate herbivores, resulting in susceptible and resistant branches within a single canopy. These mosaic trees provide a unique opportunity to explore the biosynthesis and genetic regulation of chemical defences in the foliage. The biosynthesis of the principal defence compounds, terpenoid-dominated essential oils, is well understood. However, the regulation of the genes involved and thus the control of phenotypic variation within a single tree canopy remains a mystery.