The influence of modified 14-3-3 protein synthesis in potato plants on the nutritional value of the tubers

The recently created six transgenic potato genotypes with overexpressed or underexpressed P14-3-3a (29G) and P14-3-3c (20R) isoforms of 14-3-3 protein were field-trialled (1998–2001). The contents of protein, starch, reducing sugars, sucrose and lipids were determined in the transgenic and control tubers harvested from the field. The obtained results showed a significant increase in crude protein content in potatoes with repression of P14-3-3c isoform and in potatoes with blocked P14-3-3a synthesis in comparison to the control line. A stable increase in lipid content of potatoes with overexpression of 14-3-3 protein from Cucurbita pepo in the field trials was observed. The variability of the investigated genotypes, in respect to the nutritional components, was statistically analysed using discriminant function and cluster analyses. The dominant influence of the variability of the genotypes exerted significant differentiation of protein, lipid and starch contents. These components showed the greatest discriminant power in the variability of genotypes. These results confirm the suggestion that 14-3-3 protein co-ordinates primary metabolite synthesis in plants.