Circadian autonomy and rhythmic precision of the Arabidopsis female reproductive organ

The plant circadian clock regulates essential biological processes including flowering time or petal move-ment. However, little is known about how the clock functions in flowers. Here, we identified the circadian components and transcriptional networks contributing to the generation of rhythms in pistils, the female reproductive organ. When detached from the rest of the flower, pistils sustain highly precise rhythms, indi-cating organ-specific circadian autonomy. Analyses of clock mutants and chromatin immunoprecipitation assays showed distinct expression patterns and specific regulatory functions for clock activators and repres-sors in pistils. Genetic interaction studies also suggested a hierarchy of the repressing activities that provide robustness and precision to the pistil clock. Globally, the circadian function in pistils primarily governs re-sponses to environmental stimuli and photosynthesis and controls pistil growth and seed weight and produc-tion. Understanding the circadian intricacies in reproductive organs may prove useful for optimizing plant reproduction and productivity.

Automated summary

This study identified the circadian components and transcriptional networks involved in generating rhythms in pistils. It revealed that pistils have organ-specific circadian autonomy and that clock activators and repressors have distinct expression patterns and regulatory functions. Genetic interaction studies also showed a hierarchy of repressing activities that contribute to the robustness and precision of the pistil clock. Additionally, the study found that circadian function in pistils primarily governs responses to environmental stimuli and photosynthesis, and controls pistil growth and seed production.