| Potato is the third most important food crop in the world after rice and wheat. Because of its widely distributed cultivation and high yields, it is considered a critical species in terms of food security in face of a growing world population. However, potato is particularly vulnerable to high temperature during various stages of its life cycle. Elevated temperatures strongly suppress tuberisation, negatively affect storage and shelf life of tubers and reduce fitness of seed potatoes. Breeding new heat-stress tolerant cultivars is an urgent need for sustainable increases in potato production, given the negative impact of the rises in temperature due to global warming. In this project, an integrated approach will be used by combining physiology, genetics, genomics, metabolomics and natural variation studies to analyze the impact of elevated temperatures on (1) sink-source relations of potato plants, (2) potato tuber development, (3) starch accumulation and tuber quality and (4) tuber dormancy. To achieve these aims both unbiased and targeted approaches will be employed. The unbiased approaches include the elucidation of phenotypic, biochemical and molecular responses to varying environmental conditions of selected potato genotypes (diploid populations, and a panel of tetraploid varieties and GMPs). Environmental conditions will include elevated and ambient temperatures in combination with different day lengths and light intensities. The plants will be phenotyped with respect to assimilate allocation, tuberisation, tuber yield, quality and dormancy. The genetic approach aims at identifying polymorphisms of candidate genes from diploid populations exhibiting a wide response to elevated temperatures. This will lead to the identification of genes and allelic variants that confer heat tolerance. The targeted approach is based on recent breakthroughs of the partners, which show that two linked regulators (StCDF_V and StSP6A) play a central role in the initiation of tuberisation. Our unpublished work suggests that StSP6A over-expression confers heat tolerance in transgenic potato plants. Therefore, the role of these regulators will be investigated in more detail in order to identify key components of the multiple signal transduction pathway(s). In addition levels of phytohormones known to regulate tuber initiation and dormancy will be modified and their impact on heat tolerance will be investigated. |