Lawes Trust studentship award for a joint project between the University of Reading and Rothamsted Research.

Lettuce (Lactuca spp) is an important leafy vegetable crop from the Asteraceae that is the principal component of most salads. Consumption of fresh salads has increased in response to the public health campaign to eat 5-a-day but the increase is small compared to that seen for fruit crops as consumers find the taste of vegetables less attractive than fruit. One of the problems facing lettuce growers and retailers is that many consumers are reluctant to consume lettuce as they perceive the taste to be bitter and unpalatable. Major components contributing towards the bitter taste of lettuce are isoprenoids such as sesquiterpenoid lactones (SLs) which are highly concentrated within latex the principal component of the milky exudate that is released from lettuce upon wounding. These secondary metabolites appear to be synthesised by the plant as a defence against fungal and microbial pathogens, but the SLs are also thought to have analgesic, antitussive and sedative properties in humans.

A combined molecular genetic, metabolic and sensory approach will be used to answer the following primary questions:

• Can regions of the lettuce genome, and potentially candidate genes, be identified that regulate SL conjugate biosynthesis?
• Are 15-oxalyl and 8-sulfate conjugates of SLs stable during shelf life of commercial Lactuca species?
• Is the consumer perception of bitterness changed in lines quantitatively altered in 8-sulfate conjugates?

The information from the above questions will yield tools for developing commercial lettuce varieties with more appeal to the consumer palate and give a fundamental insight into the genetic basis of SL conjugate biosynthesis.

The project is expected to commence in October 2007 and will include a stipend to cover the students living expenses at the University of Reading and Rothamsted Research (Hertfordshire). The student will be expected to spend time at both institutions.

For more details of the project please contact Dr Carol Wagstaff at the Department of Food Biosciences, University of Reading (c.wagstaff@reading.ac.uk) or Dr Mike Beale at Rothamsted Research (mike.beale@bbsrc.ac.uk).