Garlic-derived polysulfides as growth stimulants in grape cultivation: Unravelling the biochemical mechanisms

A key stage in the perennial life cycle of grapevines is the period of "winter chill" which trigger oxidative stress pathways that stimulate emergence from winter dormancy (bud break). Bud break efficiency affects the quality and uniformity of subsequent fruit production. To compensate for winter chill deficits (increasingly exacerbated by climate change) hydrogen cyanamide is widely employed to chemically stimulate bud break.

However, its toxicity to farm workers, and many animals demonstrates a need for more sustainable treatments.

Garlic extracts offer an appealing, environmentally benign, alternative bud break stimulant, which poses less risk to humans and animal welfare. The most prominent bioactive components in garlic extracts are a series of unusual organosulfur molecules known as diallylpolysulfides (DAPS) whose antibacterial activity is attributed to reactions with thiol cofactors, which perturbs their intracellular redox status. "Winter chill" induces bud break via similar mechanisms, so it is plausible that DAPS could do the same.

In collaboration with ECOspray (http://www.ecospray.com/) this project aims to: 1. Elucidate the redox-based mechanisms of DAPS on bud break in perennial fruits crops. 2. Establish the dosage/timing effects of DAPS on bud break in UK and overseas field trials. 3. Subsequently develop a garlic-derived "green" bud break stimulant for use in grape farming.

This project offers extensive interdisciplinary research training in: a. Analytical Biochemistry b. Natural product purification (and potentially synthesis) c. Commercial field trial design & implementation (in collaboration with Ecospray Ltd)

There are also excellent opportunities to work closely with Ecospray to translate the collective discoveries on this project into an environmentally sustainable Garlic-derived bud break stimulant for use in grapes and other perennial fruit crops

The project will suit a student with undergraduate training in biological chemistry, biochemistry or a related discipline.