Identification of the transcription factors and (epi)genetic elements that control the vitamin C content in apple fruits.
The saying ‘an apple a day keeps the doctor away’ accurately summarises that apples are full of healthy compounds. Vitamin C is one of them and it is particularly interesting because it acts both as a vitamin and as an antioxidant. Studies carried out at the Laboratory for Fruit Breeding and Biotechnology have shown that the vitamin C concentration of apple fruits can vary up to 10-fold between cultivars. Since vitamin C is not only crucial for human nutrition, but can also improve the storability of apples, our research aims to discover the main factors that regulate its concentration. We will carry out a screening to select apple cultivars with extremely high and low vitamin C amounts out of 100 different cultivars. The vitamin C content of these genotypes will be measured during fruit development and storage. An RNA-sequencing analysis will then reveal which transcripts are differentially expressed between genotypes and time points with a different amount of vitamin C. This information will be used i) to identify master (upstream) regulators of the vitamin C metabolism ii) to find genetic variants that are tightly linked to the differences in vitamin C content and iii) to identify genes whose transcription is possibly affected by DNA methylation or other epigenetic forms. An epigenetics study of selected promoters will complete the picture of the vitamin C metabolism by showing which DNA properties apart from the nucleotide sequence are key for the vitamin C content.