Circadian rhythms driving a fast-paced root clock implicate species-specific regulation in Medicago truncatula

• 作者: Liping Wang Anqi Zhou Jing Li Mingkang Yang Fan Bu Liangfa Ge Liang Chen Wei Huang
• 来源期刊: 植物学报（英文版）
• 年，卷（期）: 2021,（8）
• 所属期刊栏目: Molecular Physiology
• 页码范围: 1537-1554
• 页数: 18页
• 语种: 英文

摘要

Plants have a hierarchical circadian structure comprising multiple tissue-specific oscillators that operate at different speeds and regulate the expression of distinct sets of genes in different organs. However, the identity of the genes differ-entially regulated by the circadian clock in different organs, such as roots, and how their oscillations create functional specialization remain unclear. Here, we profiled the diurnal and circadian landscapes of the shoots and roots of Medicago truncatula and identified the conserved regulatory sequences contributing to tran-scriptome oscillations in each organ. We found that the light-dark cycles strongly affect the global transcriptome oscillation in roots, and many clock genes oscillate only in shoots. Moreover, many key genes involved in nitrogen fixation are regulated by circadian rhythms. Surprisingly, the root clock runs faster than the shoot clock, which is contrary to the hierarchical circadian structure showing a slow-paced root clock in both detached and intact Arabidopsis thaliana (L.) Heynh. roots. Our result provides important clues about the species-specific cir-cadian regulatory mechanism, which is often overlooked, and possibly coordinates the timing between shoots and roots independent of the current prevailing model.