Annual review of plant biology最新文献

The plant circadian clock enables the precise timing of physiological processes across the day-night cycle by generating endogenous 24-h rhythms in gene expression. In Arabidopsis, an iteration between experiments and modeling has uncovered a core oscillator comprising interlocked transcriptional feedback loops. However, emerging techniques now reveal that circadian dynamics vary across organs, tissues, and even individual cells, highlighting the need for spatially resolved clock models. In this review, we explore evidence for spatial variation in clock regulation, including differences in sensitivity to environmental cues, the timing of clock components, and the nature of downstream outputs. We discuss how local cellular rhythms are coordinated to achieve robust organism-level timing and consider how spatial regulation of the clock may contribute to the control of diverse developmental processes.

Gravitropism allows plants to reorient their growth along the gravity vector by sensing and responding to changes in orientation. This review summarizes recent advances in elucidating the molecular mechanisms underlying gravity sensing and signal transduction, with a focus on flowering plants. Central to this process are starch-filled amyloplasts that sediment within statocytes and activate downstream signaling pathways. Recent discoveries include the identification of LAZY1-LIKE family proteins, which translocate from amyloplasts to the plasma membrane in response to gravistimulation and recruit regulators such as RLDs and D6PKs to control polar auxin transport. We also discuss the emerging concept of antigravitropic offset, which modulates lateral organ angles, and its potential mechanistic divergence from classical gravitropism. Collectively, these findings reveal an integrated system to regulate organ orientation and plant architecture.

All organisms fuel and build themselves through their energy metabolism. While classic biochemistry conceptualizes the fluxes of energy and matter, our understanding of how energy metabolism works in vivo contains major gaps. One reason is that energy metabolism spans multiple scales, from enzymes to organs, and shifts dynamically at environmental and developmental transitions, resulting in a degree of complexity that is presently impossible to capture. Genetically encoded fluorescent biosensors have started to bridge several critical gaps by enabling live monitoring of metabolites across scales. Recently, several paradigms of energy metabolism have started to shift, driven by the expansion of biosensing tools. This review explores advancements in our understanding of plant energy metabolism driven by fluorescent protein biosensing, highlights emerging concepts and open questions, and discusses how available tools, and much-needed future innovations, can unlock the potential of biosensing toward understanding in vivo plant energy metabolism and its effective modification.

Plant hormones are essential small molecules that regulate plant growth, development, and systemic responses to environmental stimuli. These processes are mediated by complex signaling networks involving structurally diverse receptors, regulatory proteins, and dynamic protein-protein interactions. Advances in structural and functional biology over the past two decades have revealed how hormone receptors recognize their ligands and how they mediate responses from perception to signaling through transduction pathways and feedback regulation. In this review, we summarize the current knowledge of plant hormone receptors with experimentally determined structures and highlight their central roles in shaping plant biology. Finally, we discuss outstanding questions in the field and how emerging computational tools may help address these gaps.

The advent of spatial and quantitative biology has led to immense advances in understanding the complex inner workings of plants, down to the molecular scale. Functional imaging of live plants, which enables the spatial and quantitative mapping of biochemical cues, physicochemical properties of cellular structures, and the dynamics of physical and chemical signals with unprecedented resolution, has become a key technology for advancing the mechanistic understanding of plant cell biology. In this review, we highlight progress in live functional imaging in plants through the use and development of chemical fluorescent probes, which enable plant functional imaging without requiring genetic manipulation of the study object. We explain how probes sense, target, and report on functional features within the plant cell; discuss their limitations, including toxicity; and provide case studies to exemplify how these tools can complement biological studies to unravel the complex machinery that makes plants work. We conclude by outlining the expected future development of this field and identifying key challenges that lie ahead.

Nicotinamide adenine dinucleotide (NAD) is an essential coenzyme in cellular metabolism with a long-established role in energy production, biosynthesis, and oxidative stress responses. Recent research demonstrates that NAD hydrolysis is a key step in immune signaling, beyond its primary metabolic functions. Here, we review how NAD and NAD-derived small molecules influence defense-related processes including reactive oxygen species production, calcium dynamics, and immune activation. We introduce diverse NAD-modifying enzymes in plants and discuss how they regulate immunity, with a special emphasis on Toll/interleukin 1 receptor (TIR) domain proteins, which hydrolyze NAD+ to produce immune-activating molecules. We also discuss how pathogens use NAD-modifying enzymes as virulence factors to manipulate host defenses, highlighting NAD metabolism as a newly emerged, critical battleground in the plant-pathogen arms race. Recent developments in this aspect of pathogenesis offer new opportunities to enhance disease resistance.

Grasses (Poaceae) dominate many natural and agricultural ecosystems. Grasses form longitudinal leaves with parallel venation and highly specialized, graminoid stomatal complexes. Theoretical concepts and experimental studies highlight that these anatomical features contribute to physiologically innovative properties, including enhanced capacity and dynamics of water transport and gas exchange. The genetic and molecular regulators underlying vein and epidermal patterning in grasses continue to be elucidated in model species, though integration of these processes is lacking. This review summarizes our current understanding of leaf vein and leaf epidermal development, describes the morphological and physiological characteristics of grass leaves, and highlights those related to water transport pathways and gas exchange. We conclude that an integrative anatomical and physiological framework linking water transport supply and demand must be considered for developmental research and novel crop design. This will enable an understanding of the causes and consequences of anatomical patterns of diverse grass leaves and their translational potential for agriculture in a changing climate.

RAF-like protein kinases constitute a major subclass of mitogen-activated protein kinase kinase kinases (MAPKKKs) in plants and function as critical regulators of stress and hormone signaling pathways. Unlike their animal counterparts, plant RAF kinases show extensive expansion and diversification, with distinct subgroups (B and C) exhibiting both conserved and specialized functions. Recent studies have unveiled their pivotal roles in sensing environmental stresses, such as hyperosmotic stress and elevated CO₂, as well as in mediating hormonal responses, including those to abscisic acid (ABA), ethylene, and auxin. RAFs also participate in guard cell signaling, immune responses, and developmental processes, integrating diverse external and internal cues. This review summarizes the current knowledge of plant RAF kinases, emphasizing their functional diversity, mechanisms of activation, and physiological relevance in plant adaptation.

Epitranscriptomics, the study of dynamic and site-specific RNA modifications, has emerged as a crucial layer of gene regulation in plants, paralleling the role of classical epigenetic mechanisms such as DNA and histone modifications. Among these, N  6-methyladenosine (m6A) has been identified as a central mark involved in the control of the delicate gene expression patterns during plant development and stress responses. This review highlights recent advances in characterizing m6A distribution, identifying its regulatory components, and deciphering its molecular functions, with an emphasis on insights from Arabidopsis. We further explore its roles in developmental transitions, environmental adaptation, and epigenetic plasticity. By elucidating the multilayered functions of m6A, we underscore its application as a target for crop improvement with epitranscriptome-based yield enhancement and programmable gene editing, offering new frontiers for precision agriculture.

γ-Aminobutyric acid (GABA), a nonproteinogenic amino acid first identified in biological systems over 70 years ago, has long been recognized as a metabolic intermediate. More recently, GABA has also been acknowledged as a signaling molecule that couples physiological responses to metabolic status. This review presents a conceptual framework for how metabolism sets GABA concentration and localization, which then modulates ion transport and membrane potential dynamics to influence plant growth, development, and adaptation to stress. We explore the emerging network of GABA's interactions with other signaling pathways, highlighting its involvement in environmental sensing and internal regulatory mechanisms via hormones and reactive oxygen species. These interactions influence key physiological processes including stomatal regulation, pathogen and herbivore defense, root growth, and even the modulation of flavor. Collectively, these findings position GABA as a metabolic signal integrator of plant physiological status and responses, with broad implications for enhancing crop stress resilience and food quality.