The Specialised Metabolite Dhurrin Plays Important Roles in the Growth and Biotic and Abiotic Stress Responses

Sorghum produces dhurrin, a toxic cyanogenic compound, known to act in defense against herbivores but that may also be involved in plant growth and development, and in mitigating oxidative stress. This thesis examines physiological and genetic factors affecting the deployment of dhurrin. Using acyanogenic mutants, it is shown that dhurrin is required for normal plant growth; that synthesis can be induced by the hormone, methyl jasmonate; and it may act as an antioxidant. The effectiveness of sorghum transformation techniques to eliminate dhurrin synthesis are also demonstrated. The work shows that engineering plants to alter the production of natural plant products can have inadvertent effects.