Pathway-based analysis of anthocyanin diversity in diploid potato.

Anthocyanin biosynthesis is one of the most studied pathways in plants due to the important ecological role played by these compounds and the potential health benefits of anthocyanin consumption. Given the interest in identifying new genetic factors underlying anthocyanin content we studied a diverse collection of diploid potatoes by combining a genome-wide association study and pathway-based analyses. By using an expanded SNP dataset, we identified candidate genes that had not been associated with anthocyanin variation in potatoes, namely a Myb transcription factor, a Leucoanthocyanidin dioxygenase gene and a vacuolar membrane protein. Importantly, a genomic region in chromosome 10 harbored the SNPs with strongest associations with anthocyanin content in GWAS. Some of these SNPs were associated with multiple anthocyanin compounds and therefore could underline the existence of pleiotropic genes or anthocyanin biosynthetic clusters. We identified multiple anthocyanin homologs in this genomic region, including four transcription factors and five enzymes that could be governing anthocyanin variation. For instance, a SNP linked to the phenylalanine ammonia-lyase gene, encoding the first enzyme in the phenylpropanoid biosynthetic pathway, was associated with all of the five anthocyanins measured. Finally, we combined a pathway analysis and GWAS of other agronomic traits to identify pathways related to anthocyanin biosynthesis in potatoes. We found that methionine metabolism and the production of sugars and hydroxycinnamic acids are genetically correlated to anthocyanin biosynthesis. The results contribute to the understanding of anthocyanins regulation in potatoes and can be used in future breeding programs focused on nutraceutical food.

Influence of genotype, agro-climatic conditions, cooking method, and their interactions on individual carotenoids and hydroxycinnamic acids contents in tubers of diploid potatoes.

The effects of genotype, agro-climatic conditions (ACC), and cooking method as well as their interactions on the content of individual carotenoids and hydroxycinnamic acids in different potato tubers were evaluated. While zeaxanthin content was highly influenced by the ACC (up to 631-fold change), chlorogenic acid was similarly influenced by the cooking method (up to 3.1-fold increase after cooking), by the interactions ACC × cooking method (up to 2.1-fold increase) and genotype × cooking method (up to 1.7-fold increase). Stability/extractability of compounds after cooking was found to be genotype and ACC dependent, which suggest that genotype and ACC induces differential expression of genes for the biosynthesis pathways of carotenoids and hydroxycinnamic acids is different among, as well as components of the cellular matrix. These results are promising to apply in potato breeding programs with the perspective to develop new potato cultivars selected by their nutritional attributes.