2025-11-07 カリフォルニア工科大学(Caltech)
<関連情報>
- https://www.caltech.edu/about/news/precision-genetic-engineering-points-to-a-future-of-sustainable-agriculture
- https://www.science.org/doi/10.1126/science.adu9798
- https://www.cell.com/cell/fulltext/S0092-8674(25)00196-5
ブラシノステロイドの潜在能力を解き放つ:精密植物工学への道 Unlocking the potential of brassinosteroids: A path to precision plant engineering
Nemanja Vukašinović, Trevor M. Nolan, and Eugenia Russinova
Science Published:6 Nov 2025
DOI:https://doi.org/10.1126/science.adu9798
Editor’s summary
Brassinosteroids are plant hormones with multiple roles in development and stress responses. They are perceived by plasma membrane receptors and act locally within cells through a well-established signaling pathway. Vukašinović et al. reviewed how advances in single-cell analysis and developments in gene editing are paving the way for precision engineering of crop plants. The authors propose that tissue-specific manipulation of brassinosteroid action may help to improve crop growth and avoid the unwanted systemic effects of brassinosteroid misregulation. —Madeleine Seale
Structured Abstract
BACKGROUND
Brassinosteroids are a class of plant steroid hormones that play a central role in regulating growth and development. Plants deficient in brassinosteroid biosynthesis or signaling are severely dwarfed and often sterile. Brassinosteroids are positive regulators of both cell proliferation and cell elongation, processes essential for organ formation and overall plant architecture. Brassinosteroid-related transcription factors regulate the expression of thousands of genes. These include core cell cycle genes needed for cell cycle progression and cell wall–loosening genes necessary for cell elongation. The brassinosteroid signaling pathway is among the best characterized in plants, with its core signaling components well defined. Nevertheless, ongoing research continues to uncover additional regulators, expanding our understanding of this complex network. In several crop species, manipulation of brassinosteroid pathways has led to enhanced yields. Yet we still do not understand how to precisely produce trait improvements without trade-offs. Further exploration of strategies to fine-tune brassinosteroid signaling holds promise for advancing crop improvement.
ADVANCES
Single-cell technologies, along with proteomics and protein-protein interaction studies, have deepened our understanding of the brassinosteroid signaling pathway. These findings highlight how brassinosteroid signaling can vary even between neighboring cells, pointing to the highly localized regulation required for coordinated organ growth. Long-term live-cell imaging has enabled the visualization of brassinosteroid biosynthesis and signaling at the cellular level, particularly in tissues such as root meristems, revealing the specific functions of brassinosteroid signaling in dividing cells. Alongside these findings, the study of brassinosteroid distribution and transport has begun to challenge earlier assumptions. Whereas brassinosteroids were once thought to act locally, or even in an autocrine manner owing to their low mobility, recent evidence suggests limited intercellular transport, contributing to tissue-wide coordination of growth. These discoveries indicate that brassinosteroid homeostasis is maintained not only through signaling-biosynthesis feedback loops but also through controlled hormone distribution. In addition, several noncanonical modulators, which do not involve hormone binding to the receptor, have been identified. Together, these technological and conceptual advances have refined our understanding of brassinosteroid signaling in regulating plant growth and development.
OUTLOOK
Broad disruption of brassinosteroid signaling leads to severe dwarfism in both Arabidopsis and crop species. These phenotypes underscore the importance of understanding brassinosteroid function in a tissue- and organ-specific context to design improved crop traits without detrimental side effects. In recent years, several studies have demonstrated that tissue-specific manipulation of brassinosteroids can substantially enhance yield in various economically important crops. These insights can inform the strategies used to engineer brassinosteroid pathways in a more targeted and effective manner. Looking ahead, we anticipate the application of genetic tools that will enable spatially restricted modulation of brassinosteroid signaling and distribution. This goal can already be achieved using CRISPR-Cas systems in combination with tissue-specific promoters. To support these efforts, it will be essential to further characterize brassinosteroid signaling networks in crop species and identify candidate genes with desirable expression profiles. Research in crops may uncover additional brassinosteroid regulators uniquely suited to crop-specific genetic engineering. These strategies for manipulating the brassinosteroid pathway hold promise for enhancing crop yield while minimizing growth trade-offs.
Advances in fundamental brassinosteroid research provide insights for crop improvement.
Understanding the role of brassinosteroid signaling in fundamental developmental processes, such as cell proliferation and cell elongation, has the potential to inform the precise engineering of improved crop traits.
Abstract
Brassinosteroids are essential plant hormones that play a central role in regulating growth, development, and stress responses. Their impact on plant architecture and productivity makes them attractive targets for crop improvement. Recent findings reveal that brassinosteroid signaling is more complex than previously thought, involving multiple layers of regulation and cross-talk with other pathways. Cutting-edge technologies, such as single-cell analysis, proteomics, and advanced imaging in model plants, are beginning to uncover this complexity at cellular resolution. Applying these tools to crop species could reveal previously unknown signaling components and enable precise plant engineering. Because mutations in this pathway often cause widespread, unintended effects, future strategies must focus on fine-tuned tissue- or organ-specific modulation. This Review highlights how new insights could drive innovative, targeted crop enhancement.
極性誘導による不均一な有糸分裂は増殖中の植物根細胞におけるブラシノステロイドの活性を制御する Polarity-guided uneven mitotic divisions control brassinosteroid activity in proliferating plant root cells
Nemanja Vukašinović ∙ Che-Wei Hsu ∙ Marco Marconi ∙ … ∙ Krzysztof Wabnik, ∙ Trevor M. Nolan ∙ Eugenia Russinova
Cell Published:March 10, 2025
DOI:https://doi.org/10.1016/j.cell.2025.02.011
Highlights
- Brassinosteroid activity fluctuates across the cell cycle, peaking during the G1 phase
- Polarity-guided mitotic divisions establish differential signaling in daughter cells
- One daughter cell supports signaling, while the other enhances hormone biosynthesis
- Uneven brassinosteroid circumvents feedback loops, thus enhancing meristem activity
Summary
Brassinosteroid hormones are positive regulators of plant organ growth, yet their function in proliferating tissues remains unclear. Here, through integrating single-cell RNA sequencing with long-term live-cell imaging of the Arabidopsis root, we reveal that brassinosteroid activity fluctuates throughout the cell cycle, decreasing during mitotic divisions and increasing during the G1 phase. The post-mitotic recovery of brassinosteroid activity is driven by the intrinsic polarity of the mother cell, resulting in one daughter cell with enhanced brassinosteroid signaling, while the other supports brassinosteroid biosynthesis. The coexistence of these distinct daughter cell states during the G1 phase circumvents a negative feedback loop to facilitate brassinosteroid production while signaling increases. Our findings uncover polarity-guided, uneven mitotic divisions in the meristem, which control brassinosteroid hormone activity to ensure optimal root growth.
