Peter Bramley

Carotenoids are a group of major plant pigments responsible for most of the yellow to red colours of flowers, fruits and vegetables. In the diet they act as powerful antioxidants and are believed to protect the body against free radical attack and hence reduce the incidence of cataracts, heart disease and certain cancers.

One approach to increasing the dietary intake of carotenoids is to increase their levels in fruit and vegetables. In order to achieve this goal, it Is necessary to understand how plants control the formation and accumulation of carotenoids, using biochemical, molecular biology and electron microscopy techniques. Currently, we are focusing on the tomato in order to elevate the levels of the three major carotenoids in ripe fruit, lycopene, ß-carotene and astaxanthin.

Carotenoid genes isolated from plants and bacteria and encoding key enzymes in the pathway have been introduced into the tomato by genetic transformation using Agrobacterium-based vectors. The transgenic plants are analysed for pigment content by HPLC, gene expression (northern and western blotting, RT-PCR), plastid ultrastructure and antioxidant potential. We are also analysing a large number of introgression lines of tomato by metabolomics in order to identify quantitative trait loci (QTLs) that can be used in plant breeding to produce elite lines that have elevated levels of antioxidants.

We are also developing a systems biology approach to predicting the metabolic control of isoprenoid biosynthesis and accumulation in tomato.

• False labelling of foods
• Adulteration of foods
• Toxic compounds in foods
• GM ingredients in foods and feeds.
• Identification of animal proteins in feeds.