Increasing lifespan in carrots: determining the molecular and metabolic mechanisms that underpin the blackening phenomenon in cut carrots

The project is focussed on carrots, which are the major UK root vegetable crop, with over 700,000 tons produced every year. Twenty two billion carrot seeds are planted every year, producing around 100 carrots per year per person in the UK. The crop covers about 9,000 hectares of farmland, having a sales value of over £290 million. Freshly harvested carrots are distributed to shops throughout Britain on almost every day of the year. Hence, carrots are harvested in the UK over almost 12 months of the year using a range of different techniques. However, serious problems arise with cut products from carrots harvested in later months of the year. In particular, the shelf life of carrot strips is very short because they have a tenancy to turn black.

This project seeks to find a solution to this financially serious problem to the industry by determining the molecular and metabolic mechanisms that underpin the blackening phenomenon in cut carrots. We will achieve this goal by firstly by characterizing the profiles of metabolites, pigments and antioxidants in carrots harvested from the field over the 12 month period and link this to susceptibility to blackening after cutting.

Secondly, we will also characterize the metabolite and transcript profiles that accompany the blackening process in cut carrots, determining in particular if this is linked to the production of reactive oxygen species, secondary metabolites and programmed cell death. Thirdly, we will determine whether these processes also occur or can be induced in carrot cells growing in culture. If this is the case, the cell culture system will be used to analyse compounds that have the potential to delay blackening.

Fourthly, we will develop molecular and protein markers for carrot senescence and a pre-disposition to blackening. We will determine whether these markers can be used to predict susceptibility to blackening. Finally, we will determine the role of phytohormones and environmental effectors that influence the senescence of harvested carrots and identify factors/processes by which the susceptibility to blackening can be decreased.