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Mérai Z, Xu F, Musilek A, Ackerl F, Khalil S, Soto-Jiménez LM, Lalatović K, Klose C, Tarkowská D, Turečková V, Strnad M, Mittelsten Scheid O. Phytochromes mediate germination inhibition under red, far-red, and white light in Aethionema arabicum. PLANT PHYSIOLOGY 2023; 192:1584-1602. [PMID: 36861637 PMCID: PMC10231562 DOI: 10.1093/plphys/kiad138] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 11/22/2022] [Accepted: 12/19/2022] [Indexed: 06/01/2023]
Abstract
The view on the role of light during seed germination stems mainly from studies with Arabidopsis (Arabidopsis thaliana), where light is required to initiate this process. In contrast, white light is a strong inhibitor of germination in other plants, exemplified by accessions of Aethionema arabicum, another member of Brassicaceae. Their seeds respond to light with gene expression changes of key regulators converse to that of Arabidopsis, resulting in opposite hormone regulation and prevention of germination. However, the photoreceptors involved in this process in A. arabicum remain unknown. Here, we screened a mutant collection of A. arabicum and identified koy-1, a mutant that lost light inhibition of germination due to a deletion in the promoter of HEME OXYGENASE 1, the gene for a key enzyme in the biosynthesis of the phytochrome chromophore. koy-1 seeds were unresponsive to red- and far-red light and hyposensitive under white light. Comparison of hormone and gene expression between wild type and koy-1 revealed that very low light fluence stimulates germination, while high irradiance of red and far-red light is inhibitory, indicating a dual role of phytochromes in light-regulated seed germination. The mutation also affects the ratio between the 2 fruit morphs of A. arabicum, suggesting that light reception via phytochromes can fine-tune several parameters of propagation in adaptation to conditions in the habitat.
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Affiliation(s)
- Zsuzsanna Mérai
- Gregor Mendel Institute of Molecular Plant Biology (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna 1030, Austria
| | - Fei Xu
- Gregor Mendel Institute of Molecular Plant Biology (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna 1030, Austria
| | - Andreas Musilek
- Technical University of Vienna, TRIGA Center Atominstitut, Vienna 1020, Austria
| | - Florian Ackerl
- Gregor Mendel Institute of Molecular Plant Biology (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna 1030, Austria
| | - Sarhan Khalil
- Gregor Mendel Institute of Molecular Plant Biology (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna 1030, Austria
| | - Luz Mayela Soto-Jiménez
- Gregor Mendel Institute of Molecular Plant Biology (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna 1030, Austria
| | - Katarina Lalatović
- Gregor Mendel Institute of Molecular Plant Biology (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna 1030, Austria
| | - Cornelia Klose
- Institute of Biology II, University of Freiburg, Freiburg D-79104, Germany
| | - Danuše Tarkowská
- Laboratory of Growth Regulators, Palacký University & Institute of Experimental Botany, Czech Academy of Sciences, Olomouc CZ-78371, Czech Republic
| | - Veronika Turečková
- Laboratory of Growth Regulators, Palacký University & Institute of Experimental Botany, Czech Academy of Sciences, Olomouc CZ-78371, Czech Republic
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Palacký University & Institute of Experimental Botany, Czech Academy of Sciences, Olomouc CZ-78371, Czech Republic
| | - Ortrun Mittelsten Scheid
- Gregor Mendel Institute of Molecular Plant Biology (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna 1030, Austria
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Carta A, Fernández-Pascual E, Gioria M, Müller JV, Rivière S, Rosbakh S, Saatkamp A, Vandelook F, Mattana E. Climate shapes the seed germination niche of temperate flowering plants: a meta-analysis of European seed conservation data. ANNALS OF BOTANY 2022; 129:775-786. [PMID: 35303062 PMCID: PMC9292614 DOI: 10.1093/aob/mcac037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 03/16/2022] [Indexed: 05/29/2023]
Abstract
BACKGROUND AND AIMS Interactions between ecological factors and seed physiological responses during the establishment phase shape the distribution of plants. Yet, our understanding of the functions and evolution of early-life traits has been limited by the scarcity of large-scale datasets. Here, we tested the hypothesis that the germination niche of temperate plants is shaped by their climatic requirements and phylogenetic relatedness, using germination data sourced from a comprehensive seed conservation database of the European flora (ENSCOBASE). METHODS We performed a phylogenetically informed Bayesian meta-analysis of primary data, considering 18 762 germination tests of 2418 species from laboratory experiments conducted across all European geographical regions. We tested for the interaction between species' climatic requirements and germination responses to experimental conditions including temperature, alternating temperature, light and dormancy-breaking treatments, while accounting for between-study variation related to seed sources and seed lot physiological status. KEY RESULTS Climate was a strong predictor of germination responses. In warm and seasonally dry climates the seed germination niche includes a cold-cued germination response and an inhibition determined by alternating temperature regimes and cold stratification, while in climates with high temperature seasonality opposite responses can be observed. Germination responses to scarification and light were related to seed mass but not to climate. We also found a significant phylogenetic signal in the response of seeds to experimental conditions, providing evidence that the germination niche is phylogenetically constrained. Nevertheless, phylogenetically distant lineages exhibited common germination responses under similar climates. CONCLUSION This is the first quantitative meta-analysis of the germination niche at a continental scale. Our findings showed that the germination niches of European plants exhibit evolutionary convergence mediated by strong pressures at the macroclimatic level. In addition, our methodological approach highlighted how large datasets generated by conservation seed banking can be valuable sources to address questions in plant macroecology and evolution.
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Affiliation(s)
| | | | - Margherita Gioria
- Czech Academy of Sciences, Institute of Botany, Department of Invasion Ecology, Průhonice, Czech Republic
| | | | | | - Sergey Rosbakh
- Ecology and Conservation Biology, University of Regensburg, Regensburg, Germany
| | - Arne Saatkamp
- Aix Marseille Université, Université d’Avignon, CNRS, IRD, IMBE, Marseille, France
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Blandino C, Fernández-Pascual E, Newton RJ, Pritchard HW. Regeneration from seed in herbaceous understorey of ancient woodlands of temperate Europe. ANNALS OF BOTANY 2022; 129:761-774. [PMID: 35020780 PMCID: PMC9292608 DOI: 10.1093/aob/mcac003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 01/07/2022] [Indexed: 05/29/2023]
Abstract
BACKGROUND AND AIMS European ancient woodlands are subject to land use change, and the distribution of herbaceous understorey species may be threatened because of their poor ability to colonize isolated forest patches. The regeneration niche can determine the species assembly of a community, and seed germination traits may be important descriptors of this niche. METHODS We analysed ecological records for 208 herbaceous species regarded as indicators of ancient woodlands in Europe and, where possible, collated data on seed germination traits, reviewed plant regeneration strategies and measured seed internal morphology traits. The relationship between plant regeneration strategies and ecological requirements was explored for 57 species using ordination and classification analysis. KEY RESULTS Three regeneration strategies were identified. Species growing in closed-canopy areas tend to have morphological seed dormancy, often requiring darkness and low temperatures for germination, and their shoots emerge in early spring, thus avoiding the competition for light from canopy species. These species are separated into two groups: autumn and late winter germinators. The third strategy is defined by open-forest plants with a preference for gaps, forest edges and riparian forests. They tend to have physiological seed dormancy and germinate in light and at higher temperatures, so their seedlings emerge in spring or summer. CONCLUSION Seed germination traits are fundamental to which species are good or poor colonizers of the temperate forest understorey and could provide a finer explanation than adult plant traits of species distribution patterns. Seed dormancy type, temperature stratification and light requirements for seed germination are important drivers of forest floor colonization patterns and should be taken in account when planning successful ecological recovery of temperate woodland understories.
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Affiliation(s)
| | - Eduardo Fernández-Pascual
- Science Directorate, Royal Botanic Gardens, Kew, Wakehurst, Ardlingly, West Sussex, UK
- IMIB – Biodiversity Research Institute, University of Oviedo, Mieres, Spain
| | - Rosemary J Newton
- Science Directorate, Royal Botanic Gardens, Kew, Wakehurst, Ardlingly, West Sussex, UK
| | - Hugh W Pritchard
- Science Directorate, Royal Botanic Gardens, Kew, Wakehurst, Ardlingly, West Sussex, UK
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Wang J, Xu G, Chen W, Ma Y, Qi W, Zhang C, Cui X. Impacts of growth form and phylogenetic relatedness on seed germination: A large-scale analysis of a subtropical regional flora. Ecol Evol 2021; 11:1280-1293. [PMID: 33598130 PMCID: PMC7863672 DOI: 10.1002/ece3.7132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 11/12/2020] [Accepted: 11/17/2020] [Indexed: 11/16/2022] Open
Abstract
Plant regeneration strategy plays a critical role in species survival and can be used as a proxy for the evolutionary response of species to climate change. However, information on the effects of key plant traits and phylogenetic relatedness on seed germination is limited at large regional scales that vary in climate. To test the hypotheses that phylogenetic niche conservatism plays a critical force in shaping seed ecophysiological traits across species, and also drives their response to climatic fluctuation, we conducted a controlled experiment on seed germination and determined the percentage and rate of germination for 249 species in subtropical China under two temperature regimes (i.e., daily 25°C; daily alternating 25/15°C for each 12 hr). Germination was low with a skewed distribution (mean = 38.9% at 25°C, and 43.3% at 25/15°C). One fifth of the species had low (<10%) and slow (4-30 days) germination, and only a few (8%) species had a high (>80%) and rapid (1.2-6.6 days) germination. All studied plant traits (including germination responses) showed a significant phylogenetic signal, with an exception of seed germination percentage under the alternating temperature scenario. Generalized linear models (GLMs) and phylogenetic generalized estimation equations (GEEs) demonstrated that growth form and seed dispersal mode were strong drivers of germination. Our experimental study highlights that integrating plant key traits and phylogeny is critical to predicting seed germination response to future climate change.
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Affiliation(s)
- JuHong Wang
- College of Food Technology and Life ScienceHanshan Normal UniversityChaozhouChina
| | - GeXi Xu
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland AdministrationResearch Institute of Forest Ecology, Environment and ProtectionChinese Academy of ForestryBeijingChina
| | - Wen Chen
- College of Geography and Tourism ManagementHanshan Normal UniversityChaozhouChina
| | - YanBo Ma
- College of Mathematics and StatisticsHanshan Normal UniversityChaozhouChina
| | - Wei Qi
- State Key Laboratory of Grassland AgroecosystemsSchool of Life SciencesLanzhou UniversityLanzhouChina
| | - ChunHui Zhang
- State Key Laboratory of Plateau Ecology and AgricultureQinghai UniversityXiningChina
| | - XianLiang Cui
- College of Biology and ChemistryPuer UniversityPuerChina
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Huarte HR, Puglia GD, Prjibelski AD, Raccuia SA. Seed Transcriptome Annotation Reveals Enhanced Expression of Genes Related to ROS Homeostasis and Ethylene Metabolism at Alternating Temperatures in Wild Cardoon. PLANTS 2020; 9:plants9091225. [PMID: 32961840 PMCID: PMC7570316 DOI: 10.3390/plants9091225] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/09/2020] [Accepted: 09/13/2020] [Indexed: 12/20/2022]
Abstract
The association among environmental cues, ethylene response, ABA signaling, and reactive oxygen species (ROS) homeostasis in the process of seed dormancy release is nowadays well-established in many species. Alternating temperatures are recognized as one of the main environmental signals determining dormancy release, but their underlying mechanisms are scarcely known. Dry after-ripened wild cardoon achenes germinated poorly at a constant temperature of 20, 15, or 10 °C, whereas germination was stimulated by 80% at alternating temperatures of 20/10 °C. Using an RNA-Seq approach, we identified 23,640 and annotated 14,078 gene transcripts expressed in dry achenes and achenes exposed to constant or alternating temperatures. Transcriptional patterns identified in dry condition included seed reserve and response to dehydration stress genes (i.e., HSPs, peroxidases, and LEAs). At a constant temperature, we observed an upregulation of ABA biosynthesis genes (i.e., NCED9), ABA-responsive genes (i.e., ABI5 and TAP), as well as other genes previously related to physiological dormancy and inhibition of germination. However, the alternating temperatures were associated with the upregulation of ethylene metabolism (i.e., ACO1, 4, and ACS10) and signaling (i.e., EXPs) genes and ROS homeostasis regulators genes (i.e., RBOH and CAT). Accordingly, the ethylene production was twice as high at alternating than at constant temperatures. The presence in the germination medium of ethylene or ROS synthesis and signaling inhibitors reduced significantly, but not completely, germination at 20/10 °C. Conversely, the presence of methyl viologen and salicylhydroxamic acid (SHAM), a peroxidase inhibitor, partially increased germination at constant temperature. Taken together, the present study provides the first insights into the gene expression patterns and physiological response associated with dormancy release at alternating temperatures in wild cardoon (Cynara cardunculus var. sylvestris).
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Affiliation(s)
- Hector R. Huarte
- CONICET/Faculty of Agricultural Sciences, National University of Lomas de Zamora, 1836 Llavallol, Argentina;
| | - Giuseppe. D. Puglia
- Institute for Agricultural and Forestry Systems in the Mediterranean (ISAFoM), Department of Biology, Agriculture and Food Science (DiSBA), National Research Council (CNR), Via Empedocle, 58, 95128 Catania, Italy;
- Correspondence: ; Tel.: +39-0956139914
| | - Andrey D. Prjibelski
- Center for Algorithmic Biotechnology, Institute of Translational Biomedicine, St. Petersburg State University, 199004 St. Petersburg, Russia;
| | - Salvatore A. Raccuia
- Institute for Agricultural and Forestry Systems in the Mediterranean (ISAFoM), Department of Biology, Agriculture and Food Science (DiSBA), National Research Council (CNR), Via Empedocle, 58, 95128 Catania, Italy;
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Mérai Z, Graeber K, Wilhelmsson P, Ullrich KK, Arshad W, Grosche C, Tarkowská D, Turečková V, Strnad M, Rensing SA, Leubner-Metzger G, Mittelsten Scheid O. Aethionema arabicum: a novel model plant to study the light control of seed germination. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3313-3328. [PMID: 30949700 PMCID: PMC6598081 DOI: 10.1093/jxb/erz146] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 03/08/2019] [Indexed: 05/07/2023]
Abstract
The timing of seed germination is crucial for seed plants and is coordinated by internal and external cues, reflecting adaptations to different habitats. Physiological and molecular studies with lettuce and Arabidopsis thaliana have documented a strict requirement for light to initiate germination and identified many receptors, signaling cascades, and hormonal control elements. In contrast, seed germination in several other plants is inhibited by light, but the molecular basis of this alternative response is unknown. We describe Aethionema arabicum (Brassicaceae) as a suitable model plant to investigate the mechanism of germination inhibition by light, as this species has accessions with natural variation between light-sensitive and light-neutral responses. Inhibition of germination occurs in red, blue, or far-red light and increases with light intensity and duration. Gibberellins and abscisic acid are involved in the control of germination, as in Arabidopsis, but transcriptome comparisons of light- and dark-exposed A. arabicum seeds revealed that, upon light exposure, the expression of genes for key regulators undergo converse changes, resulting in antipodal hormone regulation. These findings illustrate that similar modular components of a pathway in light-inhibited, light-neutral, and light-requiring germination among the Brassicaceae have been assembled in the course of evolution to produce divergent pathways, likely as adaptive traits.
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Affiliation(s)
- Zsuzsanna Mérai
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr-Gasse, Vienna, Austria
| | - Kai Graeber
- School of Biological Sciences, Plant Molecular Science and Centre for Systems and Synthetic Biology, Royal Holloway University of London, Egham, Surrey, UK
| | - Per Wilhelmsson
- Plant Cell Biology, Faculty of Biology, University of Marburg, Karl-von-Frisch-Str., Marburg, Germany
| | - Kristian K Ullrich
- Plant Cell Biology, Faculty of Biology, University of Marburg, Karl-von-Frisch-Str., Marburg, Germany
| | - Waheed Arshad
- School of Biological Sciences, Plant Molecular Science and Centre for Systems and Synthetic Biology, Royal Holloway University of London, Egham, Surrey, UK
| | - Christopher Grosche
- Plant Cell Biology, Faculty of Biology, University of Marburg, Karl-von-Frisch-Str., Marburg, Germany
| | - Danuše Tarkowská
- Laboratory of Growth Regulators, The Czech Academy of Sciences, Institute of Experimental Botany & Palacký University, Šlechtitelů, Olomouc, Czech Republic
| | - Veronika Turečková
- Laboratory of Growth Regulators, The Czech Academy of Sciences, Institute of Experimental Botany & Palacký University, Šlechtitelů, Olomouc, Czech Republic
| | - Miroslav Strnad
- Laboratory of Growth Regulators, The Czech Academy of Sciences, Institute of Experimental Botany & Palacký University, Šlechtitelů, Olomouc, Czech Republic
| | - Stefan A Rensing
- Plant Cell Biology, Faculty of Biology, University of Marburg, Karl-von-Frisch-Str., Marburg, Germany
| | - Gerhard Leubner-Metzger
- School of Biological Sciences, Plant Molecular Science and Centre for Systems and Synthetic Biology, Royal Holloway University of London, Egham, Surrey, UK
- Laboratory of Growth Regulators, The Czech Academy of Sciences, Institute of Experimental Botany & Palacký University, Šlechtitelů, Olomouc, Czech Republic
| | - Ortrun Mittelsten Scheid
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr-Gasse, Vienna, Austria
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