Professor Michigan State University East Lansing, Michigan
Body of Abstract: Many plant species display natural variation in the circadian period. However, the role of this variation for adaptation to different environments is not fully understood. We are investigating natural variation of circadian traits in potato. Using a ~200 wild accessions panel we confirmed a correlation between the circadian period and the latitude of origin. Indicating a function of the clock in adaptation to different daylengths. However, we also observed a significant correlation between the circadian period and the elevation of origin, indicating that other environmental factors also play a role in this phenomenon. To investigate the function of the circadian period under different daylengths we analyzed gene expression in a short (S. candolleanum) and a long (S. chacoense) wild potato species at a 2 h resolution. It has been hypothesized that the circadian period influences the timing of expression under light/dark cycles, such that a short circadian period would lead to earlier peak of gene expression of circadian regulated genes. The opposite would occur for longer circadian periods. In spite of the differences in the free running period between the three genotypes, we did not observe genome-wide unidirectional changes in the phase of gene expression under light/dark cycles. However, we observed that a set of putative circadian associated genes displayed an earlier phase of expression in S. candolleanum than in S. chacoense in accordance to the faster circadian clock of the former.