427 / 2019-01-28 21:38:32

Natural variation of circadian rhythms across 191 Arabidopsis accessions from Sweden

Circadian Rhythms,Natural variation,Temperature,GWAS

全体主题 > Photobiology

A fully functioning circadian clock, well matched to its external environment has long been acknowledged to be crucial to the fitness of an individual. However, the extent of circadian rhythm adaption in natural populations is still not completely understood. In this study, we have focused on a collection of Arabidopsis accessions from across a large latitudinal range in Sweden; a country with variations in climatic, anthropogenic and day-length factors all potentially influencing clock adaption. We screened 191 Swedish accessions for their circadian characteristics using delayed fluorescence imaging. This revealed a 4.42h difference in period between accessions exhibiting the fastest and slowest rhythms. Mean periods were found to be significantly correlated with latitude of origin. We applied genome-wide association mapping to identify genetic polymorphisms underlying the diversity in period, peak-phase and relative amplitude error of these rhythms. Promising candidate genes identified in regions significantly associated with period and phase variation, were taken forward for a mutant screen. We also selected accessions representative of the tails of phenotypic variation for these traits and conducted experiments to see whether divergence persisted at 22°C, 16°C and 10°C. This ongoing research demonstrates the adaptive capability of the circadian clock in Arabidopsis and uncovers the genetic polymorphisms mediating these effects.