植物生物钟在农业生产中应对全球变暖的应用

当前全球变暖趋势不可逆转,异常气候导致的温度胁迫频繁发生,给农业高产及稳产带来了巨大挑战。生物钟作为内源性且可遗传的计时机制,赋予了植物预测和快速响应环境因子周期性变化的能力,以确保诸多生理生化途径与环境同步,极大增强了植物的生存和繁衍能力。温度响应和补偿现象不仅涉及生物钟与环境信号“同步化”,而且涉及农业生产中作物适应温度胁迫的实际应用。生物钟温度补偿是指在较宽范围的生理温度内,通过转录和转录后机制,生物钟可基本维持近日节律周期的长度不变,确保计时机制准确运行。自然环境中,光照、温度和湿度紧密耦联,作为授时因子将环境信号经过输入途径传递给生物钟核心振荡器,影响植物生长发育的全过程。该文回顾了植物生物钟温度响应和补偿机制的研究历史,详述了最新研究进展,展望了其在作物遗传育种和田间管理等方面的应用前景,为解决农作物温度胁迫适应性问题提供了全新的思路和方案。

COR27 and COR28 encode nighttime repressors integrating Arabidopsis circadian clock and cold response

Summary It was noted that circadian components function in plant adaptation to diurnal temperature cycles and freezing tolerance. Our genome-wide transcriptome analysis revealed that evening-phased COR27 and COR28 mainly repress the transcription of clockassociated evening genes PRRS, ELF4 and cold-responsive genes. Chromatin immunoprecipitation indicated that CCAI is recruited to the site containing EE elements of COR27 and COR28 promoters in a temperaturedependent way. Further genetic analysis shows COR28 is essential for the circadian function of PRR9 and PRRT. Together, our results support a role of COR27 and COR28 as nighttime repressors integrating circadian clock and plant cold stress responses.

Circadian clock in plants:Linking timing to fitness

Endogenous circadian clock integrates cyclic signals of environment and daily and seasonal behaviors of organisms to achieve spatiotemporal synchronization,which greatly improves genetic diversity and fitness of species.This review addresses recent studies on the plant circadian system in the field of chronobiology,covering topics on molecular mechanisms,internal and external Zeitgebers,and hierarchical regulation of physiological outputs.The architecture of the circadian clock involves the autoregulatory transcriptional feedback loops,post-translational modifications of core oscillators,and epigenetic modifications of DNA and histones.Here,light,temperature,humidity,and internal elemental nutrients are summarized to illustrate the sensitivity of the circadian clock to timing cues.In addition,the circadian clock runs cell-autonomously,driving independent circadian rhythms in various tissues.The core oscillators responds to each other with biochemical factors including calcium ions,mineral nutrients,photosynthetic products,and hormones.We describe clock components sequentially expressed during a 24-h day that regulate rhythmic growth,aging,immune response,and resistance to biotic and abiotic stresses.Notably,more data have suggested the circadian clock links chrono-culture to key agronomic traits in crops.

The circadian clock ticks in plant stress responses

The circadian clock,a time-keeping mechanism,drives nearly 24-h self-sustaining rhythms at the physiological,cellular,and molecular levels,keeping them synchronized with the cyclic changes of environmental signals.The plant clock is sensitive to external and internal stress signals that act as timing cues to influence the circadian rhythms through input pathways of the circadian clock system.In order to cope with environmental stresses,many core oscillators are involved in defense while maintaining daily growth in various ways.Recent studies have shown that a hierarchical multi-oscillator network orchestrates the defense through rhythmic accumulation of gene transcripts,alternative splicing of mRNA precursors,modification and turnover of proteins,subcellular localization,stimuli-induced phase separation,and long-distance transport of proteins.This review summarizes the essential role of circadian core oscillators in response to stresses in Arabidopsis thaliana and crops,including daily and seasonal abiotic stresses(low or high temperature,drought,high salinity,and nutrition deficiency)and biotic stresses(pathogens and herbivorous insects).By integrating time-keeping mechanisms,circadian rhythms and stress resistance,we provide a temporal perspective for scientists to better understand plant environmental adaptation and breed high-quality crop germplasm for agricultural production.

LNKs-RVEs complex ticks in the circadian gating of plant temperature stress responses

Recently,Kidokoro et al.found that protein complex LNK3,4-RVE4,8 and LNK1,2-RVE4,8 of the circadian clock modulates plant cold-and high-temperature tolerance,respectively.Here,we reviewed the discovery of LNKs,the dynamically formed morning-phased clock complexes,and their critical role on endogenous circadian rhythms.In addition,we summarized the research work on LNKs with the interacting proteins RVEs,CCA1 in temperature responses and discussed how the circadian clock confer increased fitness via gating the rhythmic expression of their target genes.