Donald (Don) Grierson is a geneticist who studies biological ageing and food quality in plants. His work to genetically engineer edible plants has made a major impact upon agriculture and food production. Don created a genetically modified tomato, which ripened more slowly, giving it a much longer shelf life. A puree made from Donald’s tomatoes was the first genetically modified food  be sold in the United Kingdom.

Tomatoes are a useful model organism in which to study the ripening of climacteric fruit. Such fruit produces the plant hormone ethylene as it ripens, and also includes apples, bananas, melons and apricots. Donald focuses on identifying the mechanisms involved in the process of ripening and has helped to clarify the function of genes in the biological ageing process.

His research led to the first application to plants of a method to suppress the expression of certain genes within cells — now known as gene silencing. Donald has received a number of honours for his exceptional research including, in 2000, an OBE for his services to plant gene regulation.