Annual review of plant biology最新文献

Plant cells are defined by their walls, which, in addition to providing structural support and shape, are an integral component of the nonliving extracellular space called the apoplast. Cell wall thickenings are present in many different root cell types. They come in a variety of simple and more complex structures with varying composition of lignin and suberin and can change in response to environmental stressors. The majority of these root cell wall thickenings and cell types that contain them are absent in the model plant Arabidopsis thaliana despite being present in most plant species. As a result, we know very little regarding their developmental control and function. Increasing evidence suggests that these structures are critical for responding to and facilitating adaptation to a wide array of stresses that a plant root experiences. These structures function in blocking apoplastic transport, oxygen, and water loss and enhancing root penetrative strength. In this review, we describe the most common types of cell wall thickenings in the outer cell types of plant roots-the velamen, exodermal thickenings, the sclerenchyma, and phi thickenings. Their cell-type dependency, morphology, composition, environmental responsiveness, and genetic control in vascular plants are discussed, as well as their potential to generate more stress-resilient roots in the face of a changing climate.

I grew up with laboratory glassware and microscopes as treasures from a young age. I was a member of the Chemistry Club in junior high school, and when I visited RIKEN with club members, I wished to become an organic chemist in the future. I received my doctoral degree through the study of the spawning inhibitor of starfish. I became a researcher at RIKEN and identified the chemical structure of a mating pheromone of a yeast. As a plant biochemist, I studied a cell-free system of gibberellins at the University of Göttingen and tried to identify the gibberellin biosynthetic pathways in plants and clone gibberellin biosynthetic enzyme genes to understand the light regulation of plant growth. I also worked on biosynthetic enzymes of abscisic acid, indole acetic acid, and brassinosteroids. I developed a special interest in the oxygenases of plant hormone biosynthesis, cytochrome P450 monooxygenases, 2-oxoglutartae-dependent dioxygenase, molybdenum cofactor-containing oxidase, and flavin-containing monooxygenase.

A single reference genome does not fully capture species diversity. By contrast, a pangenome incorporates multiple genomes to capture the entire set of nonredundant genes in a given species, along with its genome diversity. New sequencing technologies enable researchers to produce multiple high-quality genome sequences and catalog diverse genetic variations with better precision. Pangenomic studies have detected structural variants in plant genomes, dissected the genetic architecture of agronomic traits, and helped unravel molecular underpinnings and evolutionary origins of plant phenotypes. The pangenome concept has further evolved into a so-called superpangenome that includes wild relatives within a genus or clade and shifted to graph-based reference systems. Nevertheless, building pangenomes and representing complex structural variants remain challenging in many crops. Standardized computing pipelines and common data structures are needed to compare and interpret pangenomes. The growing body of plant pangenomics data requires new algorithms, huge data storage capacity, and training to help researchers and breeders take advantage of newly discovered genes and genetic variants.

The DELLA genes, also referred to as Green Revolution genes, encode conserved master growth regulators in plants. The nuclear-localized DELLA proteins are transcription regulators that interact with hundreds of transcription factors and other transcription regulators. They not only function as gibberellin signaling repressors in vascular plants but also play a central role in coordinating diverse signaling pathways in response to both internal hormonal signals and external cues (e.g., light and nutrient conditions, biotic and abiotic stresses). Through a combination of genetic, genomic, biochemical, and structural studies, significant advances have been made in understanding both the functional domains and motifs within DELLAs and the molecular mechanisms underlying their function. Here, we highlight new insights into the molecular workings of DELLA proteins, including an evolutionary perspective.

Initially identified as a key regulator of female fertility in Arabidopsis, the FERONIA (FER) receptor kinase is now recognized as crucial for almost all aspects of plant growth and survival. FER partners with a glycosylphosphatidylinositol-anchored protein of the LLG family to act as coreceptors on the cell surface. The FER-LLG coreceptor interacts with different RAPID ALKALINIZATION FACTOR (RALF) peptide ligands to function in various growth and developmental processes and to respond to challenges from the environment. The RALF-FER-LLG signaling modules interact with molecules in the cell wall, cell membrane, cytoplasm, and nucleus and mediate an interwoven signaling network. Multiple FER-LLG modules, each anchored by FER or a FER-related receptor kinase, have been studied, illustrating the functional diversity and the mechanistic complexity of the FER family signaling modules. The challenges going forward are to distill from this complexity the unifying schemes where possible and attain precision and refinement in the knowledge of critical details upon which future investigations can be built. By focusing on the extensively characterized FER, this review provides foundational information to guide the next phase of research on FER in model as well as crop species and potential applications for improving plant growth and resilience.

B vitamins are a source of coenzymes for a vast array of enzyme reactions, particularly those of metabolism. As metabolism is the basis of decisions that drive maintenance, growth, and development, B vitamin-derived coenzymes are key components that facilitate these processes. For over a century, we have known about these essential compounds and have elucidated their pathways of biosynthesis, repair, salvage, and degradation in numerous organisms. Only now are we beginning to understand their importance for regulatory processes, which are becoming an important topic in plants. Here, I highlight and discuss emerging evidence on how B vitamins are integrated into vital processes, from energy generation and nutrition to gene expression, and thereby contribute to the coordination of growth and developmental programs, particularly those that concern maintenance of a stable state, which is the foundational tenet of plant homeostasis.

Auxins, a group of central hormones in plant growth and development, are transported by a diverse range of transporters with distinct biochemical and structural properties. This review summarizes the current knowledge on all known auxin transporters with respect to their biochemical and biophysical properties and the methods used to characterize them. In particular, we focus on the recent advances that were made concerning the PIN-FORMED family of auxin exporters. Insights derived from solving their structures have improved our understanding of the auxin export process, and we discuss the current state of the art on PIN-mediated auxin transport, including the use of biophysical methods to examine their properties. Understanding the mechanisms of auxin transport is crucial for understanding plant growth and development, as well as for the development of more effective strategies for crop production and plant biotechnology.

Red and far-red light-sensing phytochromes are widespread in nature, occurring in plants, algae, fungi, and prokaryotes. Despite at least a billion years of evolution, their photosensory modules remain structurally and functionally similar. Conversely, nature has found remarkably different ways of transmitting light signals from the photosensor to diverse physiological responses. We summarize key features of phytochrome structure and function and discuss how these are correlated, from how the bilin environment affects the chromophore to how light induces cellular signals. Recent advances in the structural characterization of bacterial and plant phytochromes have resulted in paradigm changes in phytochrome research that we discuss in the context of present-day knowledge. Finally, we highlight questions that remain to be answered and suggest some of the benefits of understanding phytochrome structure and function.

Photosynthesis has been using energy from sunlight to assimilate atmospheric CO₂ for at least 3.5 billion years. Through evolution and natural selection, photosynthetic organisms have flourished in almost all aquatic and terrestrial environments. This is partly due to the diversity of light-harvesting complex (LHC) proteins, which facilitate photosystem assembly, efficient excitation energy transfer, and photoprotection. Structural advances have provided angstrom-level structures of many of these proteins and have expanded our understanding of the pigments, lipids, and residues that drive LHC function. In this review, we compare and contrast recently observed cryo-electron microscopy structures across photosynthetic eukaryotes to identify structural motifs that underlie various light-harvesting strategies. We discuss subtle monomer changes that result in macroscale reorganization of LHC oligomers. Additionally, we find recurring patterns across diverse LHCs that may serve as evolutionary stepping stones for functional diversification. Advancing our understanding of LHC protein-environment interactions will improve our capacity to engineer more productive crops.

Viruses, causal agents of devastating diseases in plants, are obligate intracellular pathogens composed of a nucleic acid genome and a limited number of viral proteins. The diversity of plant viruses, their diminutive molecular nature, and their symplastic localization pose challenges to understanding the interplay between these pathogens and their hosts in the currently accepted framework of plant innate immunity. It is clear, nevertheless, that plants can recognize the presence of a virus and activate antiviral immune responses, although our knowledge of the breadth of invasion signals and the underpinning sensing events is far from complete. Below, I discuss some of the demonstrated or hypothesized mechanisms enabling viral recognition in plants, the step preceding the onset of antiviral immunity, as well as the strategies viruses have evolved to evade or suppress their detection.