| 1. |
- Bellini, Catherine, et al.
(författare)
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Adventitious roots and lateral roots : similarities and differences
- 2014
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Ingår i: Annual Review of Plant Biology. - : Annual Reviews. - 1543-5008 .- 1545-2123. - 9780824306656 ; 65, s. 639-666
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Forskningsöversikt (refereegranskat)abstract
- In addition to its role in water and nutrient uptake, the root system is fundamentally important because it anchors a plant to its substrate. Although a wide variety of root systems exist across different species, all plants have a primary root (derived from an embryonic radicle) and different types of lateral roots. Adventitious roots, by comparison, display the same functions as lateral roots but develop from aerial tissues. In addition, they not only develop as an adaptive response to various stresses, such as wounding or flooding, but also are a key limiting component of vegetative propagation. Lateral and adventitious roots share key elements of the genetic and hormonal regulatory networks but are subject to different regulatory mechanisms. In this review, we discuss the developmental processes that give rise to lateral and adventitious roots and highlight knowledge acquired over the past few years about the mechanisms that regulate adventitious root formation.
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| 2. |
- Dobrenel, Thomas, et al.
(författare)
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TOR Signaling and Nutrient Sensing
- 2016
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Ingår i: Annual Review of Plant Biology. - : Annual Reviews. - 1543-5008 .- 1545-2123. ; 67, s. 261-285
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Forskningsöversikt (refereegranskat)abstract
- All living organisms rely on nutrients to sustain cell metabolism and energy production, which in turn need to be adjusted based on available resources. The evolutionarily conserved target of rapamycin (TOR) protein kinase is a central regulatory hub that connects environmental information about the quantity and quality of nutrients to developmental and metabolic processes in order to maintain cellular homeostasis. TOR is activated by both nitrogen and carbon metabolites and promotes energy-consuming processes such as cell division, mRNA translation, and anabolism in times of abundance while repressing nutrient remobilization through autophagy. In animals and yeasts, TOR acts antagonistically to the starvation-induced AMP-activated kinase (AMPK)/sucrose nonfermenting 1 (Snf1) kinase, called Snf1-related kinase 1 (SnRK1) in plants. This review summarizes the immense knowledge on the relationship betweenTORsignaling and nutrients in nonphotosynthetic organisms and presents recent findings in plants that illuminate the crucial role of this pathway in conveying nutrient-derived signals and regulating many aspects of metabolism and growth.
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| 3. |
- Fischer, Urs, et al.
(författare)
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The Dynamics of Cambial Stem Cell Activity
- 2019
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Ingår i: Annual Review of Plant Biology. - : Annual Reviews. - 1543-5008 .- 1545-2123. ; 70, s. 293-319
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Forskningsöversikt (refereegranskat)abstract
- Stem cell populations in meristematic tissues at distinct locations in the plant body provide the potency of continuous plant growth. Primary meristems, at the apices of the plant body, contribute mainly to the elongation of the main plant axes, whereas secondary meristems in lateral positions are responsible for the thickening of these axes. The stem cells of the vascular cambium-a secondary lateral meristem-produce the secondary phloem (bast) and secondary xylem (wood). The sites of primary and secondary growth are spatially separated, and mobile signals are expected to coordinate growth rates between apical and lateral stem cell populations. Although the underlying mechanisms have not yet been uncovered, it seems likely that hormones, peptides, and mechanical cues orchestrate primary and secondary growth. In this review, we highlight the current knowledge and recent discoveries of how cambial stem cell activity is regulated, with a focus on mobile signals and the response of cambial activity to environmental and stress factors.
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| 4. |
- Hartmann, Henrik, et al.
(författare)
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Climate Change Risks to Global Forest Health : Emergence of Unexpected Events of Elevated Tree Mortality Worldwide
- 2022
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Ingår i: Annual Review of Plant Biology. - : Annual Reviews. - 1543-5008 .- 1545-2123. ; 73, s. 673-702
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Forskningsöversikt (refereegranskat)abstract
- Recent observations of elevated tree mortality following climate extremes, like heat and drought, raise concerns about climate change risks to global forest health. We currently lack both sufficient data and understanding to identify whether these observations represent a global trend toward increasing tree mortality. Here, we document events of sudden and unexpected elevated tree mortality following heat and drought events in ecosystems that previously were considered tolerant or not at risk of exposure. These events underscore the fact that climate change may affect forests with unexpected force in the future. We use the events as examples to highlight current difficulties and challenges for realistically predicting such tree mortality events and the uncertainties about future forest condition. Advances in remote sensing technology and greater availably of high-resolution data, from both field assessments and satellites, are needed to improve both understanding and prediction of forest responses to future climate change.
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| 5. |
- Hong, Lilan, et al.
(författare)
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Heterogeneity and Robustness in Plant Morphogenesis : From Cells to Organs
- 2018
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Ingår i: Annual Review of Plant Biology. - : Annual Reviews. - 1543-5008 .- 1545-2123. ; 69, s. 469-495
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Forskningsöversikt (refereegranskat)abstract
- Development is remarkably reproducible, producing organs with the same size, shape, and function repeatedly from individual to individual. For example, every flower on the Antirrhinum stalk has the same snapping dragon mouth. This reproducibility has allowed taxonomists to classify plants and animals according to their morphology. Yet these reproducible organs are composed of highly variable cells. For example, neighboring cells grow at different rates in Arabidopsis leaves, sepals, and shoot apical meristems. This cellular variability occurs in normal, wild-type organisms, indicating that cellular heterogeneity (or diversity in a characteristic such as growth rate) is either actively maintained or, at a minimum, not entirely suppressed. In fact, cellular heterogeneity can contribute to producing invariant organs. Here, we focus on how plant organs are reproducibly created during development from these highly variable cells.
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| 6. |
- Jansson, Stefan, et al.
(författare)
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Populus : A Model System for Plant Biology.
- 2007
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Ingår i: Annual Review of Plant Biology. - : Annual Reviews. - 1543-5008 .- 1545-2123. ; 58, s. 435-458
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Tidskriftsartikel (refereegranskat)abstract
- With the completion of the Populus trichocarpa genome sequence and the development of various genetic, genomic, and biochemical tools, Populus now offers many possibilities to study questions that cannot be as easily addressed in Arabidopsis and rice, the two prime model systems of plant biology and genomics. Tree-specific traits such as wood formation, long-term perennial growth, and seasonality are obvious areas of research, but research in other areas such as control of flowering, biotic interactions, and evolution of adaptive traits is enriched by adding a tree to the suite of model systems. Furthermore, the reproductive biology of Populus (a dioeceous wind-pollinated long-lived tree) offers both new possibilities and challenges in the study and analysis of natural genetic and phenotypic variation. The relatively close phylogenetic relationship of Populus to Arabidopsis in the Eurosid clade of Eudicotyledonous plants aids in comparative functional studies and comparative genomics, and has the potential to greatly facilitate studies on genome and gene family evolution in eudicots.
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| 7. |
- Köhler, Claudia, et al.
(författare)
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Epigenetic mechanisms underlying genomic imprinting in plants
- 2012
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Ingår i: Annual Review of Plant Biology. - : Annual Reviews. - 1543-5008 .- 1545-2123. ; 63, s. 331-352
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Forskningsöversikt (refereegranskat)abstract
- Genomicimprinting, the differential expression of an autosomal gene that is dependent on its parent of origin, has independently evolvedinfloweringplantsand mammals.Inboth of these organism classes,imprintingoccursinembryo-nourishing tissues-the placenta and the endosperm, respectively. It has been proposed that some imprinted genes control nutrient flow from the mother to the offspring. Genome-wide analyses of imprinted genesinplantshave revealed that many imprinted genes are locatedinthe vicinity of transposon or repeat sequences, implying that transposon insertions are associated with the evolution of imprinted loci. Imprinted expression of a number of genes is conserved between monocots and dicots, suggesting that long-term selection can maintain imprinted expression at some loci.Interms ofepigeneticmechanisms, imprinted expression is largely controlled by an antagonistic action of DNA methylation and Polycomb group-mediated histone methylationinthe vicinity of imprinted genes, whereby the position of suchepigeneticmodifications can determine whether a gene will be expressed mainly from either the maternally or paternally inherited alleles.
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| 8. |
- Liu, Sijia, et al.
(författare)
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Solving the Puzzle of Shape Regulation in Plant Epidermal Pavement Cells
- 2021
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Ingår i: Annual Review of Plant Biology. - : Annual Reviews. - 1543-5008 .- 1545-2123. ; 72, s. 525-550
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Tidskriftsartikel (refereegranskat)abstract
- The plant epidermis serves many essential functions, including interactions with the environment, protection, mechanical strength, and regulation of tissue and organ growth. To achieve these functions, specialized epidermal cells develop into particular shapes. These include the intriguing interdigitated jigsaw puzzle shape of cotyledon and leaf pavement cells seen in many species, the precise functions of which remain rather obscure. Although pavement cell shape regulation is complex and still a long way from being fully understood, the roles of the cell wall, mechanical stresses, cytoskeleton, cytoskeletal regulatory proteins, and phytohormones are becoming clearer. Here, we provide a review of this current knowledge of pavement cell morphogenesis, generated from a wealth of experimental evidence and assisted by computational modeling approaches. We also discuss the evolution and potential functions of pavement cell interdigitation. Throughout the review, we highlight some of the thought-provoking controversies and creative theories surrounding the formation of the curious puzzle shape of these cells.
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| 9. |
- Mozgova, Iva, et al.
(författare)
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The Polycomb Group Protein Regulatory Network
- 2015
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Ingår i: Annual Review of Plant Biology. - : Annual Reviews. - 1543-5008 .- 1545-2123. ; 66, s. 269-296
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Forskningsöversikt (refereegranskat)abstract
- Correct expression of specific sets of genes in time and space ensures the establishment and maintenance of cell identity, which is required for proper development of multicellular organisms. Polycomb and Trithorax group proteins form multisubunit complexes that antagonistically act in epigenetic gene repression and activation, respectively. The traditional view of Polycomb repressive complexes (PRCs) as executors of long-lasting and stable gene repression is being extended by evidence of flexible repression in response to developmental and environmental cues, increasing the complexity of mechanisms that ensure selective and properly timed PRC targeting and release of Polycomb repression. Here, we review advances in understanding of the composition, mechanisms of targeting, and function of plant PRCs and discuss the parallels and differences between plant and animal models.
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| 10. |
- Novak, Ondrej, et al.
(författare)
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Zooming In on Plant Hormone Analysis: Tissue- and Cell-Specific Approaches
- 2017
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Ingår i: Annual Review of Plant Biology. - : Annual Reviews. - 1543-5008 .- 1545-2123. ; 68, s. 323-348
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Forskningsöversikt (refereegranskat)abstract
- Plant hormones are a group of naturally occurring, low-abundance organic compounds that influence physiological processes in plants. Our knowledge of the distribution profiles of phytohormones in plant organs, tissues, and cells is still incomplete, but advances in mass spectrometry have enabled significant progress in tissue-and cell-type-specific analyses of phytohormones over the last decade. Mass spectrometry is able to simultaneously identify and quantify hormones and their related substances. Biosensors, on the other hand, offer continuous monitoring; can visualize local distributions and real-time quantification; and, in the case of genetically encoded biosensors, are noninvasive. Thus, biosensors offer additional, complementary technologies for determining temporal and spatial changes in phytohormone concentrations. In this review, we focus on recent advances in mass spectrometry-based quantification, describe monitoring systems based on biosensors, and discuss validations of the various methods before looking ahead at future developments for both approaches.
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