This five-year research programme is funded by a consortium consisting of GlaxoSmithKline, the Biotechnology and Biological Sciences Research Council, the Scottish Government and the Horticultural Research Council under the auspices of Defra’s Horticulture Link programme.  The programme which began in 2002 is a collaborative effort between scientists at SCRI responsible for much of the fundamental work and others at East Malling Research in Kent responsible for the more applied aspects of the project.

Blackcurrant fruit are naturally rich in vitamin C, containing up to four times as much as oranges on a per weight basis.  Despite the already high levels of vitamin C, there is a requirement amongst growers and processors to develop short-term agronomic methods and longer-term accelerated breeding to maximise the vitamin C content of blackcurrant fruit.

In the first part of the project, work was focussed on defining exactly how, when and where vitamin C was made within the plant and using the knowledge obtained in order to aid the design of agronomic methods to allow growers to manipulate fruit vitamin C levels.

Detailed analysis of the biochemistry and physiology of vitamin C accumulation in blackcurrant fruit has shown that the major factor contributing to vitamin accumulation is biosynthesis within the fruit itself. Comparison of low and high vitamin C cultivars has shown that fruit biosynthetic capacity is the limiting factor in vitamin C accumulation.  Analysis of historical data regarding the vitamin content of fruit grown over the past 30 years alongside detailed meteorological records has shown a correlation between post-harvest solar radiation and the fruit vitamin concentration in the following season.

This finding suggests that the capacity of the plant to store starch post harvest may impact on the fruit vitamin levels in the following year. In addition, it has suggested agronomic methods for the improvement of fruit levels using solar matting and selective pruning to allow bushes to intercept more light.

Currently, breeders have to wait two to three years after making a cross before first fruit and hence analysis of vitamin C concentrations. At this stage a number of crosses will be discarded on that criterion alone. In order to improve fruit breeding it is intended to develop predictive markers that will allow the discard of unsuitable crosses at a much earlier stage.

Breeders will therefore be able to perform more crosses in each year in the knowledge that a number of seedlings will be discarded in the first few months and that all plants taken through to maturity will have a minimum vitamin C concentration in the fruit. Initial analysis has revealed specific genetic sequences associated with high fruit vitamin C levels and further development of these markers will be undertaken through follow on funding for a PhD studentship.

Further information is available on the PDF file: publicity flyer (202 KB) for the project.

Related publications

Hancock, R.D., Walker, P.G., Pont, S.D.A., Marquis, N., Vivera, S., Gordon, S.L., Brennan, R.M., Viola, R. 2007. L-Ascorbic acid accumulation in fruit of Ribes nigrum occurs by in situ biosynthesis via the L-glactose pathway. Functional Plant Biology 34, 1080-1091.

Walker, P.G., Gordon, S.L., Brennan, R.M., Hancock, R.D. 2006. A high-throughput monolithic HPLC method for rapid vitamin C phenotyping of berry fruit. Phytochemical Analysis 17, 284-290.

Hancock, R., Brennan, R., Atkinson, C. 2006. Increasing the levels of vitamin C in blackcurrants. Grower Magazine, April 24th pp.16-17.

Viola, R., Brennan, R.M., Davies, H.V., Sommerville, L. 2000. L-Ascorbic acid accumulation in berries of Ribes nigrum L. Journal of Horticultural Science and Biotechnology 75, 409-412.