In depth study of the beta-carotene meta- and catabolism in different cassava genotypes with different yellow root color and beta-carotene content.

Cassava is one of the most important crops in the tropics with a remarkable tolerance to drought and ability to grow on poor soils. However, it has relatively low nutritional quality having dire implications for millions of people dependent on this staple crop. Particularly problematic is the low ß-carotene level, which can lead to provitamin A deficiency with severe health and economic consequences, including early mortality, impaired physical ability and blindness. Efforts to breed for varieties with increased b-carotene have therefore been undertaken, but is difficult to combine with high starch content, which is a vital trait for farmers's acceptance and the market value. The proposes a new exploratory approach by cross-species comparative genomics and molecular network analysis in combination with functional testing by genetic transformation and the emerging technique of genome editing. We do this by generating transcript, smallRNA and metabolite data of specific varieties with different genetic background and ß- carotene content to identify new candidate genes and key enzymes leading to increased ß-carotene levels and sustained starch content. We will also identify molecular signatures associated to these traits to screen existing germplasms for more lines to be incorporated in breeding programs. The findings will serve either for marker assisted breeding or as engineering approach by gene-editing to overcome possible constrains in traditional breeding.