Foxtail millet (Setaria italica), a significant C4 model crop known for its exceptional photosynthetic efficiency and robust environmental adaptability, serves as an excellent model for investigating C4 photosynthesis and crop stress resilience. When subjected to abiotic stress, foxtail millet employs a sophisticated signal transduction network to regulate its physiological processes, ensuring sustained high photosynthetic efficiency and normal growth. The mitogen-activated protein kinase (MAPK) family plays a key role in plant growth, development, and stress response. Here, we identified and named a MAPK in S. italica as SiMPK6. Fluorescence quantitative PCR analysis revealed that SiMPK6 is mainly expressed in the leaves during the early shooting stage, with induction under various abiotic stresses such as low temperature, high osmotic pressure, high salt, high temperature, and high light. Overexpressing the SiMPK6 in Arabidopsis thaliana mitigated damage to photosystem II induced by stress, underscoring the gene’s crucial role in foxtail millet’s stress signal transduction and maintenance of high photosynthetic efficiency.

This study reports the first complete mitochondrial genome of the traditional medicinal and edible crop, D. opposita (493,268 bp, 45.67% GC). We annotated 39 unique protein-coding genes (PCGs), which included 24 core mitochondrial genes and 15 variable genes, as well as 19 tRNA genes and 3 rRNA genes, along with 245 SSRs and multiple repeat sequences. The longest palindromic repeat measured 260 bp, while the longest forward repeat was 24,068 bp. Furthermore, 723 RNA editing sites were discovered, all involving C-to-U edits, with the nad4 having the highest number of edits (60 sites in total). Comparative genomic and phylogenomic analyses revealed Tiegun yam conserved gene content but structural variations compared to other monocots, underscoring the role of repetitive sequences and recombination in shaping mitochondrial architecture and facilitating cytonuclear co-adaptation. These findings establish a crucial genomic foundation for understanding mitochondrial regulation of growth and metabolic traits in this important species, with implications for future molecular breeding and functional studies of medicinal compound biosynthesis.

Earth’s rotation produces day and night cycles that are a primary selective pressure driving the evolution of endogenous circadian clocks. Cyanobacteria are the most studied prokaryotic model, and their timekeeping core is a protein oscillator composed of KaiA, KaiB, and KaiC. This oscillator sustains a near-24 h rhythm independently of transcription–translation feedback, challenging the long-standing assumption that prokaryotes merely respond passively to environmental cues. Moreover, it offers unique insights into the evolution and operational logic of circadian clocks. This review summarizes advances in cyanobacterial circadian research. We first analyze the KaiABC oscillator’s molecular basis, including synergistic conformational changes, phosphorylation and dephosphorylation cascades, and temperature compensation, which confer robustness and tunability. We compare oscillator compositions across cyanobacterial lineages, showing evolutionary plasticity. We then outline input and output networks, clarifying how environmental signals reset the oscillator phase and how temporal information is relayed to downstream processes. We further explain how the clock coordinates photosynthesis, nitrogen fixation, respiration, and cell division through predictive regulation, temporal decoupling, and resource prioritization, thereby resolving metabolic conflicts and enhancing fitness under light and dark cycles. This framework provides a theoretical basis for microbial survival strategies in fluctuating environments and offers insights for synthetic biology circuit design. Finally, we discuss open questions, including coupling between the oscillator and the cell cycle, functional divergence among ecotypes, and roles at the community level. Further research on the cyanobacterial clock will help clarify general principles of biological timing and its evolutionary origins.