Adaptive diversification in the cellular circadian behavior of Arabidopsis leaf- and root-derived cells

The plant circadian system is based on self-sustained cellular oscillations and is utilized to adapt to daily and seasonal environmental changes. The cellular circadian clocks in the above- and belowground plant organs are subjected to diverse local environments. Individual cellular clocks are affected by other cells/tissues in plants, and the intrinsic properties of cellular clocks remain to be elucidated. In this study, we showed the circadian properties of leaf- and root-derived cells of a CCA1::LUC Arabidopsis transgenic plant and demonstrated that the cells in total isolation from other cells harbor a genuine circadian clock. Quantitative and statistical analyses for individual cellular bioluminescence rhythms revealed a difference in amplitude and precision of light/dark entrainment between the two cell-types, suggesting that leaf-derived cells have a clock with a stronger persistence against fluctuating environments. Circadian systems in the leaves and roots are diversified to adapt to their local environments at the cellular level.