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ABSTRACT Developmental biology seeks to unravel the intricate regulatory mechanisms orchestrating the transformation of a single cell into a complex, multicellular organism. Dynamical systems theory provides a powerful quantitative, visual and intuitive framework for understanding this complexity. This Primer examines five core dynamical systems theory concepts and their applications to pattern formation during development: (1) analysis of phase portraits, (2) bistable switches, (3) stochasticity, (4) response to time-dependent signals, and (5) oscillations. We explore how these concepts shed light onto cell fate decision making and provide insights into the dynamic nature of developmental processes driven by signals and gradients, as well as the role of noise in shaping developmental outcomes. Selected examples highlight how integrating dynamical systems with experimental approaches has significantly advanced our understanding of the regulatory logic underlying development across scales, from molecular networks to tissue-level dynamics. 

Abstract Understanding crop plants responses to abiotic stress is increasingly important in this changing climate. We asked experts how discoveries in Arabidopsis thaliana have translated into advancements in abiotic crop stress resilience. The theme is that core regulatory networks identified in Arabidopsis are conserved in crops, but the molecular regulation varies among species. For cold tolerance, the regulatory framework is conserved, but MAP Kinase signaling promotes degradation of the INDUCER OF DREB1 EXPRESSION transcription factor in Arabidopsis but inhibits it in rice. For hypoxia, manipulation of the oxygen sensing Arg/N-degron pathway discovered in Arabidopsis has improved waterlogging and flood tolerance in barley, maize, wheat, and soybean. For light signaling, overexpression of PHYTOCHROME B reduces shade avoidance, improving yield under dense planting in potato, soybean, and maize. In rice, understanding of nitrogen responsiveness, uptake, and transport in Arabidopsis has inspired engineering of the NRT1 nitrate transceptor to increase yield. Arabidopsis research has provided leads for genetic manipulations that may improve drought resilience in crop species. Growing plants in space generates a complex array of stresses, and Arabidopsis experiments in the space station prepare for future development of robust crops as integral components of the life support systems. For environmental regulation of flowering time, the role of the GIGANTEA - CONTANS - FLOWERING LOCUS T module elucidated in Arabidopsis is largely conserved in crop plants, although additional regulators modify short-day responsiveness in rice, soybean, chrysanthemum, and potato. 

Cell migration is critical in processes such as developmental biology, wound healing, immune response, and cancer invasion/metastasis. Understanding its regulation is essential for developing targeted therapies in regenerative medicine, cancer treatment and immune modulation. This review examines cell migration mechanisms, highlighting fundamental physical principles, key molecular components, and cellular behaviors, identifying existing gaps in current knowledge, and suggesting potential directions for future research. 

One of the fundamental questions in developmental biology is how a cell is specified to differentiate as a specialized cell type. Traditionally, plant cell types were defined based on their function, location, morphology, and lineage. Currently, in the age of single-cell biology, researchers typically attempt to assign plant cells to cell types by clustering them based on their transcriptomes. However, because cells are dynamic entities that progress through the cell cycle and respond to signals, the transcriptome also reflects the state of the cell at a particular moment in time, raising questions about how to define a cell type. We suggest that these complexities and dynamics of cell states are of interest and further consider the roles signaling, stochasticity, cell cycle, and mechanical forces play in plant cell fate specification. Once established, cell identity must also be maintained. With the wealth of single-cell data coming out, the field is poised to elucidate both the complexity and dynamics of cell states. 

The emergence of tissue form in multicellular organisms results from the complex interplay between genetics and physics. In both plants and animals, cells must act in concert to pattern their behaviors. Our understanding of the factors sculpting multicellular form has increased dramatically in the past few decades. From this work, common themes have emerged that connect plant and animal morphogenesis, an exciting connection that solidifies our understanding of the developmental basis of multicellular life. In this Review we will discuss the themes and the underlying principles that connect plant and animal morphogenesis including the coordination of gene expression, signaling, growth, contraction, and mechanical and geometric feedback. 

Clinically serious congenital heart valve defects arise from improper growth and remodeling of endocardial cushions into leaflets. Genetic mutations have been extensively studied but explain less than 20% of cases. Mechanical forces generated by beating hearts drive valve development, but how these forces collectively determine valve growth and remodeling remains incompletely understood. Here, we decouple the influence of those forces on valve size and shape, and study the role of YAP pathway in determining the size and shape. The low oscillatory shear stress promotes YAP nuclear translocation in valvular endothelial cells (VEC), while the high unidirectional shear stress restricts YAP in cytoplasm. The hydrostatic compressive stress activated YAP in valvular interstitial cells (VIC), whereas the tensile stress deactivated YAP. YAP activation by small molecules promoted VIC proliferation and increased valve size. Whereas YAP inhibition enhanced the expression of cell-cell adhesions in VEC and affected valve shape. Finally, left atrial ligation was performed in chick embryonic hearts to manipulate the shear and hydrostatic stress in vivo. The restricted flow in the left ventricle induced a globular and hypoplastic left atrioventricular (AV) valves with an inhibited YAP expression. By contrast, the right AV valves with sustained YAP expression grew and elongated normally. This study establishes a simple yet elegant mechanobiological system by which transduction of local stresses regulates valve growth and remodeling. This system guides leaflets to grow into proper sizes and shapes with the ventricular development, without the need of a genetically prescribed timing mechanism.