With the sharp change of the global climate, the ecological environment for plant is becoming increasingly harsh, therefore the molecular mechanisms underlying how circadian synergistically interacts with light or temperature receptors to transmit environmental signals and rhythmically regulate various growth and development process received widespread attention. As an endogenous timer of plants, the core oscillator of circadian clock is composed of multiple coupled transcriptional-translational feedback loops (TTFL), and it is modified from transcription, post-transcription, translation, post-translation to epigenetic levels. These multi-precise regulatory mechanisms ensure that the circadian clock can be synchronized and reset by external signals, so that the endogenous rhythm matches with external cycles, thereby endowing plants with the ability to optimize resource utilization and tend towards the optimal growth, which also has an important significance for guiding the genetic improvement and domestication of crops. In this review, we summarized the multi-level of regulatory mechanisms of core oscillator as well as the molecular function of circadian homologous genes in crops, thoroughly described the interaction network between the circadian clock and the light and temperature signal pathways and give prospects for molecular breeding based on the opinion, which provides new ideas for expanding the environmental adaptability and optimizing agronomic traits of crops.

Higher plants usually start from seed germination and re-form seeds after vegetative growth and reproductive development, thus completing the life cycle. Carbohydrates, lipids, proteins, mRNA and other macromolecular substances accumulated in seeds are crucial to maintain the germination potential of seeds, some of mRNA can be preserved for a long time without degradation, known as long-lived mRNA. In rice, long-lived mRNA associated with germination began to be transcribed and accumulated 10 to 20 days after flowering, and some long-lived mRNA associated with dormancy and stress response were transcribed and preserved in cells from 20 days after flowering to seed maturity. There are many kinds of long-lived mRNA, mainly including some protein synthesis mRNA, energy metabolism mRNA, cytoskeleton mRNA and some stress response related mRNA, such as small heat shock protein, LEA (late embryogenesis abundant) family proteins. Transcriptomic analysis found that the promoter regions of many genes contain ABA- or GA-associated cis-acting elements, and there are about 500 differentially expressed long-lived mRNAs in the Arabidopsis atabi5 (ABA-insensitive 5) mutant seeds that differ from the wild type, suggesting that abscisic acid (ABA) and gibberellin (GA) are the key hormones that influence the type of long-lived mRNA. Long-lived mRNAs are usually cross-linked with a single ribosome, RNA binding protein, which exists in cells in the form of P-bodies (PBs) to protect the mRNA from degradation. However, long-lived mRNAs associated with seed dormancy are gradually degraded during seed post-ripening, and the oxidative modification of some specific long-lived mRNAs is also a biological phenomenon to break seed dormancy. During the long-term storage of seeds, the random degradation of long-lived mRNA is directly related to the life and vitality of seeds, and the retained mRNA is translated into protein to help the rapid germination of seeds in the early stage of imbibition. In this paper, the characteristics and functions of long-lived mRNA are reviewed, and some future scientific issues are discussed to provide a reference for further understanding of the molecular mechanisms of seed dormancy, germination and longevity.