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Arshad W, Steinbrecher T, Wilhelmsson PK, Fernandez-Pozo N, Pérez M, Mérai Z, Rensing SA, Chandler JO, Leubner-Metzger G. Aethionema arabicum dimorphic seed trait resetting during transition to seedlings. FRONTIERS IN PLANT SCIENCE 2024; 15:1358312. [PMID: 38525145 PMCID: PMC10957558 DOI: 10.3389/fpls.2024.1358312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 02/19/2024] [Indexed: 03/26/2024]
Abstract
The transition from germinating seeds to emerging seedlings is one of the most vulnerable plant life cycle stages. Heteromorphic diaspores (seed and fruit dispersal units) are an adaptive bet-hedging strategy to cope with spatiotemporally variable environments. While the roles and mechanisms of seedling traits have been studied in monomorphic species, which produce one type of diaspore, very little is known about seedlings in heteromorphic species. Using the dimorphic diaspore model Aethionema arabicum (Brassicaceae), we identified contrasting mechanisms in the germination responses to different temperatures of the mucilaginous seeds (M+ seed morphs), the dispersed indehiscent fruits (IND fruit morphs), and the bare non-mucilaginous M- seeds obtained from IND fruits by pericarp (fruit coat) removal. What follows the completion of germination is the pre-emergence seedling growth phase, which we investigated by comparative growth assays of early seedlings derived from the M+ seeds, bare M- seeds, and IND fruits. The dimorphic seedlings derived from M+ and M- seeds did not differ in their responses to ambient temperature and water potential. The phenotype of seedlings derived from IND fruits differed in that they had bent hypocotyls and their shoot and root growth was slower, but the biomechanical hypocotyl properties of 15-day-old seedlings did not differ between seedlings derived from germinated M+ seeds, M- seeds, or IND fruits. Comparison of the transcriptomes of the natural dimorphic diaspores, M+ seeds and IND fruits, identified 2,682 differentially expressed genes (DEGs) during late germination. During the subsequent 3 days of seedling pre-emergence growth, the number of DEGs was reduced 10-fold to 277 root DEGs and 16-fold to 164 shoot DEGs. Among the DEGs in early seedlings were hormonal regulators, in particular for auxin, ethylene, and gibberellins. Furthermore, DEGs were identified for water and ion transporters, nitrate transporter and assimilation enzymes, and cell wall remodeling protein genes encoding enzymes targeting xyloglucan and pectin. We conclude that the transcriptomes of seedlings derived from the dimorphic diaspores, M+ seeds and IND fruits, undergo transcriptional resetting during the post-germination pre-emergence growth transition phase from germinated diaspores to growing seedlings.
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Affiliation(s)
- Waheed Arshad
- Seed Biology and Technology Group, Department of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom
| | - Tina Steinbrecher
- Seed Biology and Technology Group, Department of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom
| | | | - Noe Fernandez-Pozo
- Plant Cell Biology, Faculty of Biology, University of Marburg, Marburg, Germany
- Department Plant Breeding and Physiology, Institute for Mediterranean and Subtropical Horticulture “La Mayora” (IHSM-CSIC-UMA), Málaga, Spain
| | - Marta Pérez
- Seed Biology and Technology Group, Department of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom
| | - Zsuzsanna Mérai
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Stefan A. Rensing
- Plant Cell Biology, Faculty of Biology, University of Marburg, Marburg, Germany
- Centre for Biological Signalling Studies (BIOSS), University of Freiburg, Freiburg, Germany
- Faculty of Chemistry and Pharmacy, University of Freiburg, Freiburg, Germany
| | - Jake O. Chandler
- Seed Biology and Technology Group, Department of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom
| | - Gerhard Leubner-Metzger
- Seed Biology and Technology Group, Department of Biological Sciences, Royal Holloway University of London, Egham, United Kingdom
- Laboratory of Growth Regulators, Faculty of Science, Palacký University and Institute of Experimental Botany, Czech Academy of Sciences, Olomouc, Czechia
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ROBINSON SARAH, DURAND‐SMET PAULINE. Combining tensile testing and microscopy to address a diverse range of questions. J Microsc 2020; 278:145-153. [DOI: 10.1111/jmi.12863] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 12/20/2019] [Accepted: 01/08/2020] [Indexed: 12/23/2022]
Affiliation(s)
- SARAH ROBINSON
- The Sainsbury Laboratory Cambridge University Bateman Street Cambridge UK
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Bidhendi AJ, Geitmann A. Methods to quantify primary plant cell wall mechanics. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3615-3648. [PMID: 31301141 DOI: 10.1093/jxb/erz281] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Accepted: 06/26/2019] [Indexed: 05/23/2023]
Abstract
The primary plant cell wall is a dynamically regulated composite material of multiple biopolymers that forms a scaffold enclosing the plant cells. The mechanochemical make-up of this polymer network regulates growth, morphogenesis, and stability at the cell and tissue scales. To understand the dynamics of cell wall mechanics, and how it correlates with cellular activities, several experimental frameworks have been deployed in recent years to quantify the mechanical properties of plant cells and tissues. Here we critically review the application of biomechanical tool sets pertinent to plant cell mechanics and outline some of their findings, relevance, and limitations. We also discuss methods that are less explored but hold great potential for the field, including multiscale in silico mechanical modeling that will enable a unified understanding of the mechanical behavior across the scales. Our overview reveals significant differences between the results of different mechanical testing techniques on plant material. Specifically, indentation techniques seem to consistently report lower values compared with tensile tests. Such differences may in part be due to inherent differences among the technical approaches and consequently the wall properties that they measure, and partly due to differences between experimental conditions.
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Affiliation(s)
- Amir J Bidhendi
- Department of Plant Science, McGill University, Macdonald Campus, Lakeshore, Ste-Anne-de-Bellevue, Québec, Canada
- Institut de recherche en biologie végétale, Département de sciences biologiques, Université de Montréal, Montreal, Quebec, Canada
| | - Anja Geitmann
- Department of Plant Science, McGill University, Macdonald Campus, Lakeshore, Ste-Anne-de-Bellevue, Québec, Canada
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Ilias IA, Negishi K, Yasue K, Jomura N, Morohashi K, Baharum SN, Goh HH. Transcriptome-wide effects of expansin gene manipulation in etiolated Arabidopsis seedling. JOURNAL OF PLANT RESEARCH 2019; 132:159-172. [PMID: 30341720 DOI: 10.1007/s10265-018-1067-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/19/2018] [Indexed: 05/24/2023]
Abstract
Expansin is a non-enzymatic protein which plays a pivotal role in cell wall loosening by inducing stress relaxation and extension in the plant cell wall. Previous studies on Arabidopsis, Petunia × hybrida, and tomato demonstrated that the suppression of expansin gene expression reduced plant growth but expansin overexpression does not necessarily promotes growth. In this study, both expansin gene suppression and overexpression in dark-grown transgenic Arabidopsis seedlings resulted in reduced hypocotyl length at late growth stages with a more pronounced effect for the overexpression. This defect in hypocotyl elongation raises questions about the molecular effect of expansin gene manipulation. RNA-seq analysis of the transcriptomic changes between day 3 and day 5 seedlings for both transgenic lines found numerous differentially expressed genes (DEGs) including transcription factors and hormone-related genes involved in different aspects of cell wall development. These DEGs imply that the observed hypocotyl growth retardation is a consequence of the concerted effect of regulatory factors and multiple cell-wall related genes, which are important for cell wall remodelling during rapid hypocotyl elongation. This is further supported by co-expression analysis through network-centric approach of differential network cluster analysis. This first transcriptome-wide study of expansin manipulation explains why the effect of expansin overexpression is greater than suppression and provides insights into the dynamic nature of molecular regulation during etiolation.
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Affiliation(s)
- Iqmal Asyraf Ilias
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, UKM Bangi, 43600, Selangor, Darul Ehsan, Malaysia
| | - Kohei Negishi
- Faculty of Science and Technology, Tokyo University of Science, Chiba-ken, Tokyo, 278-8510, Japan
| | - Keito Yasue
- Faculty of Science and Technology, Tokyo University of Science, Chiba-ken, Tokyo, 278-8510, Japan
| | - Naohiro Jomura
- Faculty of Science and Technology, Tokyo University of Science, Chiba-ken, Tokyo, 278-8510, Japan
| | - Kengo Morohashi
- Faculty of Science and Technology, Tokyo University of Science, Chiba-ken, Tokyo, 278-8510, Japan
| | - Syarul Nataqain Baharum
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, UKM Bangi, 43600, Selangor, Darul Ehsan, Malaysia
| | - Hoe-Han Goh
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, UKM Bangi, 43600, Selangor, Darul Ehsan, Malaysia.
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