This subproject is dedicated to exploring the roles which bioactive natural products, such as cyanogenic glucosides, play throughout various developmental stages of cyanogenic plants and other cyanogenic organisms.
Cyanogenic glucoside concentrations are extremely variable at population, whole plant, organ, tissue and cellular level and this variability can change depending on a plant’s developmental stage and/or environmental conditions. We are using several distinct plant systems to investigate how cyanogenic glucoside synthesis is regulated throughout different developmental stages and environmental conditions, with an initial focus on Eucalyptus and Sorghum. Eucalyptus offers the possibility to study the variation among the different hydroxynitrile glucosides present at the tissue level over time and in relation to environmental conditions, while in sorghum, the rapid changes in dhurrin content during seed development and the availability of the mutant collection from the TILLING program (a collaboration with Australian researchers) offer other experimental opportunities.
Our research involves characterising the function of the CYP79s from different cyanogenic Eucalyptus species by recombinant expression in yeast and transient expression in tobacco. Additionally, the trajectories of prunasin synthesis in E. cladocalyx, E. yarraensis and E. camphora are being investigated under high and low nitrogen treatments. In sorghum, we propose that cyanogenic glucosides may act as scavengers of H2O2, helping the plant to reduce damage caused by Reactive Oxygen Species (ROS) in response to environmental stressors such as high light or drought conditions. We are therefore assessing the costs and benefits of cyanogenic glucoside production under a range of environmental conditions using total cyanide deficient (tcd) mutants, with no ability to synthesise dhurrin, provided by our Australian collaborators, .