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Nagel M, Pence V, Ballesteros D, Lambardi M, Popova E, Panis B. Plant Cryopreservation: Principles, Applications, and Challenges of Banking Plant Diversity at Ultralow Temperatures. ANNUAL REVIEW OF PLANT BIOLOGY 2024; 75:797-824. [PMID: 38211950 DOI: 10.1146/annurev-arplant-070623-103551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
Progressive loss of plant diversity requires the protection of wild and agri-/horticultural species. For species whose seeds are extremely short-lived, or rarely or never produce seeds, or whose genetic makeup must be preserved, cryopreservation offers the only possibility for long-term conservation. At temperatures below freezing, most vegetative plant tissues suffer severe damage from ice crystal formation and require protection. In this review, we describe how increasing the concentration of cellular solutes by air drying or adding cryoprotectants, together with rapid cooling, results in a vitrified, highly viscous state in which cells can remain viable and be stored. On this basis, a range of dormant bud-freezing, slow-cooling, and (droplet-)vitrification protocols have been developed, but few are used to cryobank important agricultural/horticultural/timber and threatened species. To improve cryopreservation efficiency, the effects of cryoprotectants and molecular processes need to be understood and the costs for cryobanking reduced. However, overall, the long-term costs of cryopreservation are low, while the benefits are huge.
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Affiliation(s)
- Manuela Nagel
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Seeland, Germany;
| | - Valerie Pence
- Lindner Center for Conservation and Research of Endangered Wildlife (CREW), Cincinnati Zoo & Botanical Garden, Cincinnati, Ohio, USA
| | - Daniel Ballesteros
- Department of Botany and Geology, Universitat de València, Burjassot, Spain
- Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex, United Kingdom
| | - Maurizio Lambardi
- Institute of BioEconomy (IBE), National Research Council (CNR), Florence, Italy
| | - Elena Popova
- Department of Cell Biology and Biotechnology, K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia
| | - Bart Panis
- The Alliance of Bioversity International and the International Center for Tropical Agriculture (CIAT), KU Leuven, Leuven, Belgium
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Wasileńczyk U, Wawrzyniak MK, Martins JPR, Kosek P, Chmielarz P. Cryopreservation of sessile oak (Quercus petraea (Matt.) Liebl.) plumules using aluminium cryo-plates: influence of cryoprotection and drying. PLANT METHODS 2024; 20:53. [PMID: 38610046 PMCID: PMC11010404 DOI: 10.1186/s13007-024-01161-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 02/19/2024] [Indexed: 04/14/2024]
Abstract
BACKGROUND QUERCUS: seeds that are recalcitrant to desiccation and freezing temperatures cannot be stored in gene banks under conventional conditions. However, the germplasm of some recalcitrant seeded species can be stored in liquid nitrogen (-196 °C). Unfortunately, for many species, among them for almost the whole genus Quercus, an effective cryostorage method is still unknown. In this study, we propose a successful cryostorage protocol for Quercus petraea (Matt.) Liebl. germplasm using plumules (a shoot apical meristem of an embryo) frozen on aluminium cryo-plates. RESULTS: The plumules isolated from the acorns of ten provenances were prestored in 0.5 M sucrose solution (for 18 h). To form alginate beads (one plumule per bead), the plumules were placed in the wells of a cryo-plate and embedded in calcium alginate gel. For cryoprotection, the encapsulated plumules were immersed in cryoprotectant solution containing 2.0 M glycerol and different concentrations of sucrose (0.8-1.2 M) for 40 min at 25 °C and desiccated under a laminar flow cabinet for 1.0-4.0 h. Cryo-plates with plumules were directly immersed in liquid nitrogen and then cryostored for 30 min. For rewarming, cryo-plates with plumules were immersed in 1.0 M sucrose solution and rehydrated for 15 min at 25 °C. Survival rates varied from 25.8 to 83.4 were achieved after cryoprotection in 1.0 M sucrose solution and the drying of plumules for 2 h. The in vitro regrowth rate of cryopreserved plumules varied among provenances and was 26-77%. CONCLUSIONS: This study presents, for the first time, a successful, simple and effective protocol for the cryopreservation of Q. petraea germplasm that could be used in gene banks. The experiment was successfully repeated on seeds from various provenances, each yielding similar, good results. However, seed quality and storage time after harvesting are important factors in plumule regrowth after cryopreservation.
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Affiliation(s)
| | | | | | | | - Paweł Chmielarz
- Institute of Dendrology, Polish Academy of Sciences, Kórnik, Poland
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Nadarajan J, Walters C, Pritchard HW, Ballesteros D, Colville L. Seed Longevity-The Evolution of Knowledge and a Conceptual Framework. PLANTS (BASEL, SWITZERLAND) 2023; 12:471. [PMID: 36771556 PMCID: PMC9919896 DOI: 10.3390/plants12030471] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/12/2023] [Accepted: 01/14/2023] [Indexed: 06/18/2023]
Abstract
The lifespan or longevity of a seed is the time period over which it can remain viable. Seed longevity is a complex trait and varies greatly between species and even seed lots of the same species. Our scientific understanding of seed longevity has advanced from anecdotal 'Thumb Rules,' to empirically based models, biophysical explanations for why those models sometimes work or fail, and to the profound realisation that seeds are the model of the underexplored realm of biology when water is so limited that the cytoplasm solidifies. The environmental variables of moisture and temperature are essential factors that define survival or death, as well as the timescale to measure lifespan. There is an increasing understanding of how these factors induce cytoplasmic solidification and affect glassy properties. Cytoplasmic solidification slows down, but does not stop, the chemical reactions involved in ageing. Continued degradation of proteins, lipids and nucleic acids damage cell constituents and reduce the seed's metabolic capacity, eventually impairing the ability to germinate. This review captures the evolution of knowledge on seed longevity over the past five decades in relation to seed ageing mechanisms, technology development, including tools to predict seed storage behaviour and non-invasive techniques for seed longevity assessment. It is concluded that seed storage biology is a complex science covering seed physiology, biophysics, biochemistry and multi-omic technologies, and simultaneous knowledge advancement in these areas is necessary to improve seed storage efficacy for crops and wild species biodiversity conservation.
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Affiliation(s)
- Jayanthi Nadarajan
- The New Zealand Institute for Plant and Food Research Limited, Food Industry Science Centre, Palmerston North 4410, New Zealand
| | - Christina Walters
- USDA—Agricultural Research Service, National Laboratory for Genetic Resources Preservation, Fort Collins, CO 80521, USA
| | - Hugh W. Pritchard
- Royal Botanic Gardens, Kew, Wakehurst, Ardingly, Haywards Heath RH17 6TN, UK
- Chinese Academy of Sciences, Kunming Institute of Botany, Kunming 650201, China
| | - Daniel Ballesteros
- Faculty of Farmacy, Department of Botany and Geology, University of Valencia, Av. Vicent Estelles s/n, 46100 Valencia, Spain
| | - Louise Colville
- Royal Botanic Gardens, Kew, Wakehurst, Ardingly, Haywards Heath RH17 6TN, UK
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Trusiak M, Plitta-Michalak BP, Michalak M. Choosing the Right Path for the Successful Storage of Seeds. PLANTS (BASEL, SWITZERLAND) 2022; 12:72. [PMID: 36616200 PMCID: PMC9823941 DOI: 10.3390/plants12010072] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/19/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Seeds are the most commonly used source of storage material to preserve the genetic diversity of plants. However, prior to the deposition of seeds in gene banks, several questions need to be addressed. Here, we illustrate the scheme that can be used to ensure that the most optimal conditions are identified to enable the long-term storage of seeds. The main questions that need to be answered pertain to the production of viable seeds by plants, the availability of proper protocols for dormancy alleviation and germination, seed tolerance to desiccation and cold storage at -20 °C. Finally, it is very important to fully understand the capability or lack thereof for seeds or their explants to tolerate cryogenic conditions. The proper storage regimes for orthodox, intermediate and recalcitrant seeds are discussed.
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Affiliation(s)
- Magdalena Trusiak
- Department of Plant Physiology, Genetics and Biotechnology, University of Warmia and Mazury in Olsztyn, M. Oczapowskiego 1A, 10-721 Olsztyn, Poland
| | | | - Marcin Michalak
- Department of Plant Physiology, Genetics and Biotechnology, University of Warmia and Mazury in Olsztyn, M. Oczapowskiego 1A, 10-721 Olsztyn, Poland
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Xia K, Daws MI, Peng LL. Climate drives patterns of seed traits in Quercus species across China. THE NEW PHYTOLOGIST 2022; 234:1629-1638. [PMID: 35306670 DOI: 10.1111/nph.18103] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 03/03/2022] [Indexed: 05/26/2023]
Abstract
Traits enabling seeds to survive post-dispersal desiccation and subsequently germinate are important aspects of plant regeneration for species with desiccation-sensitive seeds. However, how desiccation and germination-related traits co-vary and relate to patterns of climate variation are unknown. We investigated physiological traits related to desiccation and germination of desiccation-sensitive seeds from 19 Quercus species, which typically dominate subalpine, subtropical and temperate forests in China. The results demonstrate a strong relationship between climate and seed traits consistent with a hypothesis of minimizing seed death from desiccation. Seeds of subalpine species were most desiccation sensitive and died fastest when dried. These species avoided drought and cold by germinating rapidly. Subtropical and temperate oaks had more variable strategies to minimize the risk of mortality reflecting a continuum between traits that facilitate rapid germination (with the risk of rapid desiccation) and slow germination (and slow desiccation). Across the Quercus species, the relative level of seed desiccation sensitivity, which we predicted to be important for reducing the risk of drying related mortality, was independent of climate. For desiccation-sensitive seeds this suggests a more diverse range of strategies for minimizing desiccation risk than reported previously.
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Affiliation(s)
- Ke Xia
- School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650091, Yunnan, China
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Institute of Biodiversity, Yunnan University, Kunming, 650504, Yunnan, China
| | - Matthew I Daws
- Environment Department, Alcoa of Australia Ltd, Huntly Mine, off Del Park Road, PO Box 172, Pinjarra, WA, 6208, Australia
| | - Lin-Lin Peng
- School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650091, Yunnan, China
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Institute of Biodiversity, Yunnan University, Kunming, 650504, Yunnan, China
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Cryopreservation of Holm Oak Embryogenic Cultures for Long-Term Conservation and Assessment of Polyploid Stability. PLANTS 2022; 11:plants11091266. [PMID: 35567267 PMCID: PMC9102727 DOI: 10.3390/plants11091266] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/05/2022] [Accepted: 05/05/2022] [Indexed: 11/17/2022]
Abstract
Holm oak populations are severely affected by oak decline syndrome, and reliable methods of conserving the plant material are required. A vitrification-based cryopreservation method was used for the first time for the long-term conservation of holm oak embryogenic cultures. Successful cryopreservation was achieved after determining the best developmental stage of the somatic embryos used and the optimal incubation period in plant vitrification solution 2 (PVS2). Embryos were recovered from individual nodular embryogenic structures (NES) derived from four embryogenic lines after preculture on a medium containing 0.3 M sucrose, incubation in PVS2 vitrification solution for 15 min at 25 °C and direct immersion in liquid nitrogen (LN). Embryo recovery rates of 16.7–63.3% were obtained after cryostorage for four years in LN. In addition to the embryo developmental stage and the PVS2 treatment time, the genotype can also significantly affect embryo recovery after LN storage. There were no significant differences in plant regeneration or polyploid stability between somatic embryos and plants derived from control embryos (not cryopreserved) and cryopreserved embryos. The findings indicate that embryo proliferation, plant conversion and polyploid stability are maintained in material recovered from the vitrification solution and subsequently cryopreserved.
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Liu Y, Zhang Y, Zheng Y, Nie X, Wang Y, Yu W, Su S, Cao Q, Qin L, Xing Y. Beta-Amylase and Phosphatidic Acid Involved in Recalcitrant Seed Germination of Chinese Chestnut. FRONTIERS IN PLANT SCIENCE 2022; 13:828270. [PMID: 35401618 PMCID: PMC8990265 DOI: 10.3389/fpls.2022.828270] [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: 12/03/2021] [Accepted: 02/02/2022] [Indexed: 06/14/2023]
Abstract
Chinese chestnut (Castanea mollissima), a species with recalcitrant seeds, is an important source of nuts and forest ecosystem services. The germination rate of recalcitrant seeds is low in natural habitats and decreases under conditions of desiccation and low temperature. The germination rate of cultivated Chinese chestnut seeds is significantly higher than that of wild seeds. To explore the reasons for the higher germination rate of cultivated seeds in Chinese chestnut, 113,524 structural variants (SVs) between the wild and cultivated Chinese chestnut genomes were detected through genome comparison. Genotyping these SVs in 60 Chinese chestnut accessions identified allele frequency changes during Chinese chestnut domestication, and some SVs are overlapping genes for controlling seed germination. Transcriptome analysis revealed downregulation of the abscisic acid synthesis genes and upregulation of the beta-amylase synthesis genes in strongly selected genes of cultivated seeds. On the other hand, hormone and enzyme activity assays indicated a decrease in endogenous ABA level and an increase in beta-amylase activity in cultivated seeds. These results shed light on the higher germination rate of cultivated seeds. Moreover, phosphatidic acid synthesis genes are highly expressed in seed germination stages of wild Chinese chestnut and may play a role in recalcitrant seed germination. These findings provide new insight into the regulation of wild seed germination and promote natural regeneration and succession in forest ecosystems.
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Affiliation(s)
- Yang Liu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Plant Science and Technology, Beijing University of Agriculture, Beijing, China
- Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Yu Zhang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Plant Science and Technology, Beijing University of Agriculture, Beijing, China
| | - Yi Zheng
- Bioinformatics Center, Beijing University of Agriculture, Beijing, China
| | - Xinghua Nie
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Plant Science and Technology, Beijing University of Agriculture, Beijing, China
| | - Yafeng Wang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Plant Science and Technology, Beijing University of Agriculture, Beijing, China
| | - Wenjie Yu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Plant Science and Technology, Beijing University of Agriculture, Beijing, China
| | - Shuchai Su
- Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Qingqin Cao
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Plant Science and Technology, Beijing University of Agriculture, Beijing, China
| | - Ling Qin
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Plant Science and Technology, Beijing University of Agriculture, Beijing, China
| | - Yu Xing
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, College of Plant Science and Technology, Beijing University of Agriculture, Beijing, China
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Xia K, Zhu ZQ. Characterization of physiological traits during development of the recalcitrant seeds of Quercus serrata. PLANT BIOLOGY (STUTTGART, GERMANY) 2021; 23:1000-1005. [PMID: 34310842 DOI: 10.1111/plb.13309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 06/16/2021] [Indexed: 06/13/2023]
Abstract
We investigated how developmental stage affects seed traits, including the relative level of desiccation tolerance of Quercus serrata. We tested the hypothesis that the relative level of desiccation tolerance is a quantitative trait associated with seed development and that a maximum relative level of desiccation tolerance is reached during development. Seed growth and physiological traits of Q. serrata from a subtropical forest were examined in detail during the developmental process. During seed development, the relative level of desiccation tolerance and other seed traits of Q. serrata varied. Dry matter accumulation in seed components increased rapidly beginning in mid-August, and moisture content declined. At the peak period of seed dispersal in late September, seeds were fully mature, with 100% germination. Relative level of desiccation tolerance increased up to the point of peak dispersal; however, at this time seeds were still recalcitrant. Post-mature development was accompanied by further increases in seed dry matter and decreases in moisture content, which led to a decrease in seed germination and relative level of desiccation tolerance. Our results suggest that in species with recalcitrant seeds, the relative level of desiccation tolerance and other seed traits are quantitative at the intraspecific level. The relative level of desiccation tolerance for recalcitrant seeds does not increase infinitely during phase II of development. There is a maximum relative level of desiccation tolerance in recalcitrant seeds within a species.
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Affiliation(s)
- K Xia
- Laboratory of Ecology and Evolutionary Biology, School of Ecology and Environmental Sciences, Yunnan University, Kunming, China
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, China
| | - Z-Q Zhu
- Laboratory of Ecology and Evolutionary Biology, School of Ecology and Environmental Sciences, Yunnan University, Kunming, China
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, China
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Thermotherapy and Storage Temperature Manipulations Limit the Production of Reactive Oxygen Species in Stored Pedunculate Oak Acorns. FORESTS 2021. [DOI: 10.3390/f12101338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
For many species, seed storage protocols are still being improved to provide viable seeds of the highest quality. Seed storage is extremely problematic for short-lived seeds categorized as recalcitrant, including pedunculate oak (Quercus robur L.), for which the optimal seed storage protocol involves a temperature of –3 °C and 40% acorn moisture content recommendations. The sensitivity of pedunculated oak seeds to temperature manipulations under preparation for long-term storage has been poorly investigated, particularly in terms of the production of reactive oxygen species (ROS), which are assumed to be determinants of seed longevity. Thermotherapy, the pathogen elimination procedure, did not increase the level of three types of ROS: hydrogen peroxide (H2O2), superoxide anion radical and hydroxyl radical (•OH). The temporal heat stress of thermotherapy resulted in slightly reduced levels of H2O2, indicating activation of the antioxidant systems in acorn preparation for storage. The effect of constant storage temperatures (−3, −5, −7 °C) and their combinations (−3 → −5 °C or −3 → −5 →−7 °C) on ROS levels and seed viability was investigated in three provenances. The highest ROS levels were detected in acorns stored at −7 °C, whereas three-step cold acclimation was beneficial for reducing ROS levels. Interestingly, the levels of H2O2 were not affected by temperature in thermotherapized acorns. In contrast, decreasing storage temperature caused a linear increase in •OH levels in all provenances. The effect of heat stress and cold stress on ROS levels in relation to long-term seed storage of pedunculate oak is discussed here in relation to the seed viability evidenced via germination rates, seedling emergence and electrolyte leakage. Thermotherapy and cold acclimation of acorns can improve their viability after storage by decreasing ROS levels.
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Ballesteros D, Fanega-Sleziak N, Davies RM. Cryopreservation of Seeds and Seed Embryos in Orthodox-, Intermediate-, and Recalcitrant-Seeded Species. Methods Mol Biol 2021; 2180:663-682. [PMID: 32797442 DOI: 10.1007/978-1-0716-0783-1_36] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Seeds are one of the preferable and most used sources of germplasm for the ex situ preservation of plant genetic resources. They are generally stored dry at -20 °C in seed banks following international standards. However, some seeds do not tolerate drying and/or storage at -20 °C, or present short lifespans at these conditions. For them cryopreservation is indicated for long-term preservation. When seeds tolerate desiccation (i.e., orthodox seeds), they can be dried at about 32 ± 3% relative humidity at 18 °C and stored in the vapor phase of liquid nitrogen. This is the method followed in the Millennium Seed Bank of the Royal Botanic Gardens, Kew, for wild species with short lifespans in the standard conditions of seed banks. When seeds do not tolerate desiccation (i.e., recalcitrant seeds) or their tolerance to desiccation and/or -20 °C storage is limited (i.e., intermediate seeds), drying and cooling procedures must be adjusted, and often, cryoprotection is also required. Some methods are detailed for diverse species of temperate and tropical origin.
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The Cryobiotechnology of Oaks: An Integration of Approaches for the Long-Term Ex Situ Conservation of Quercus Species. FORESTS 2020. [DOI: 10.3390/f11121281] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Conventional dry seed storage is unlikely for about one third of all tree species (and nearly half of evergreen rain forest trees) as they probably produce desiccation sensitive (recalcitrant) seeds. Consequently, international ex situ conservation targets for threatened trees will be difficult to achieve without innovation, especially in cryobiotechnology. We assessed progress in the development of various cryobiotechnology approaches for the preservation of oaks (Quercus), which are keystone species of functioning landscapes, important to the bioeconomy and under increasing threats from the spread of pests and diseases under a changing climate. Various tissues of oaks can be used for banking, from pollen grains to embryo axes. Pollen from five oak species have been shown to be highly desiccation tolerant, making dry pollen storage at low temperatures (including in liquid nitrogen) a valuable technology to support conservation and breeding programs. Somatic embryo (SE) technology and/or shoot tip in vitro technology is available for 39 species, and SE cryopreservation is routinely performed on three commercial species and shoot tips cryopreservation successful in two more species. Seed embryonic axes are the preferred explants for oak ex situ conservation, with tissue survival and regeneration of plants after cryopreservation recorded for 14 and seven species respectively; although differential responses between the shoot and root meristems in the axes are known. Dormant bud preservation seems promising, but is under-researched. Overall, these results indicate the possibility of establishing an integrated platform for the ex situ conservation of oak species based on cryobiotechnology. Challenges of explant choice, optimization of methodologies and large-scale application do remain. However, multiple approaches for the cryopreservation of oak genetic resources are available and implementation programmes should not be delayed, particularly in the centres of species diversity.
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Dissecting the Seed Maturation and Germination Processes in the Non-Orthodox Quercus ilex Species Based on Protein Signatures as Revealed by 2-DE Coupled to MALDI-TOF/TOF Proteomics Strategy. Int J Mol Sci 2020; 21:ijms21144870. [PMID: 32660160 PMCID: PMC7402289 DOI: 10.3390/ijms21144870] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 12/15/2022] Open
Abstract
Unlike orthodox species, seed recalcitrance is poorly understood, especially at the molecular level. In this regard, seed maturation and germination were studied in the non-orthodox Quercus ilex by using a proteomics strategy based on two-dimensional gel electrophoresis coupled to matrix-assisted laser desorption ionization/time of flight (2-DE-MALDI-TOF).Cotyledons and embryo/radicle were sampled at different developmental stages, including early (M1–M3), middle (M4–M7), and late (M8–M9) seed maturation, and early (G1–G3) and late (G4–G5) germination. Samples corresponding to non-germinating, inviable, seeds were also included. Protein extracts were subjected to 2-dimensional gel electrophoresis (2-DE) and changes in the protein profiles were analyzed. Identified variable proteins were grouped according to their function, being the energy, carbohydrate, lipid, and amino acid metabolisms, together with protein fate, redox homeostasis, and response to stress are the most represented groups. Beyond the visual aspect, morphometry, weight, and water content, each stage had a specific protein signature. Clear tendencies for the different protein groups throughout the maturation and germination stages were observed for, respectively, cotyledon and the embryo axis. Proteins related to metabolism, translation, legumins, proteases, proteasome, and those stress related were less abundant in non-germinating seeds, it related to the loss of viability. Cotyledons were enriched with reserve proteins and protein-degrading enzymes, while the embryo axis was enriched with proteins of cell defense and rescue, including heat-shock proteins (HSPs) and antioxidants. The peaks of enzyme proteins occurred at the middle stages (M6–M7) in cotyledons and at late ones (M8–M9) in the embryo axis. Unlike orthodox seeds, proteins associated with glycolysis, tricarboxylic acid cycle, carbohydrate, amino acid and lipid metabolism are present at high levels in the mature seed and were maintained throughout the germination stages. The lack of desiccation tolerance in Q. ilex seeds may be associated with the repression of some genes, late embryogenesis abundant proteins being one of the candidates.
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Amimi N, Dussert S, Vaissayre V, Ghouil H, Doulbeau S, Costantini C, Ammari Y, Joët T. Variation in seed traits among Mediterranean oaks in Tunisia and their ecological significance. ANNALS OF BOTANY 2020; 125:891-904. [PMID: 31904087 PMCID: PMC7218815 DOI: 10.1093/aob/mcz211] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 01/02/2020] [Indexed: 05/28/2023]
Abstract
BACKGROUND AND AIMS Oaks are the foundation and dominant tree species of most Mediterranean forests. As climate models predict dramatic changes in the Mediterranean basin, a better understanding of the ecophysiology of seed persistence and germination in oaks could help define their regeneration niches. Tunisian oaks occupy distinct geographical areas, which differ in their rainfall and temperature regimes, and are thus a valuable model to investigate relationships between seed traits and species ecological requirements. METHODS Seed morphological traits, desiccation sensitivity level, lethal freezing temperature, embryonic axis and cotyledon sugar and lipid composition, and seed and acorn germination rates at various constant temperatures were measured in Quercus canariensis, Q. coccifera, Q. ilex and Q. suber, using seeds sampled in 22 Tunisian woodlands. KEY RESULTS Only faint differences were observed for desiccation sensitivity in the oak species studied. By contrast, the species differed significantly in sensitivity to freezing, germination rates at low temperature and base temperature. Quercus ilex and Q. canariensis, which occur at high elevations where frost events are frequent, showed the lowest freezing sensitivity. A significant correlation was found between hexose contents in the embryonic axis and freezing tolerance. Significant interspecific differences in the time for seeds to germinate and the time for the radicle to pierce the pericarp were observed. The ratio of pericarp mass to acorn mass differed significantly among the species and was negatively correlated with the acorn germination rate. Quercus coccifera, which is frequent in warm and arid environments, showed the highest acorn germination rate and synchrony. CONCLUSIONS Seed lethal temperature, seed germination time at low temperatures, the ratio of pericarp mass to acorn mass and the embryonic axis hexose content appeared to be key functional traits that may influence the geographical ranges and ecological requirements of Mediterranean oaks in Tunisia.
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Affiliation(s)
- Nabil Amimi
- Laboratoire d’Ecologie Forestière, INRGREF Tunis, Rue Hédi EL Karray El Menzah IV, BP 10, 2080 Ariana, Tunisia
- Faculté des Sciences de Bizerte, Université de Carthage, 7021 Jarzouna, Tunisia
| | - Stéphane Dussert
- IRD, Université Montpellier, UMR DIADE, BP 64501, 34394 Montpellier, France
| | - Virginie Vaissayre
- IRD, Université Montpellier, UMR DIADE, BP 64501, 34394 Montpellier, France
| | - Hana Ghouil
- Faculté des Sciences de Bizerte, Université de Carthage, 7021 Jarzouna, Tunisia
| | - Sylvie Doulbeau
- IRD, Université Montpellier, UMR DIADE, BP 64501, 34394 Montpellier, France
| | | | - Youssef Ammari
- Laboratoire d’Ecologie Forestière, INRGREF Tunis, Rue Hédi EL Karray El Menzah IV, BP 10, 2080 Ariana, Tunisia
| | - Thierry Joët
- IRD, Université Montpellier, UMR DIADE, BP 64501, 34394 Montpellier, France
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14
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Ballesteros D, Pence VC. Survival and growth of embryo axes of temperate trees after two decades of cryo-storage. Cryobiology 2019; 88:110-113. [PMID: 31022387 DOI: 10.1016/j.cryobiol.2019.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/16/2019] [Accepted: 04/18/2019] [Indexed: 10/27/2022]
Abstract
Liquid nitrogen (LN) storage is recommended for conserving plants with seeds for which standard seed banking is not feasible, but there are few empirical reports confirming its long-term effectiveness. In this study we evaluated in vitro viability and ex vitro growth of embryo axes of a species that is short-lived in seed bank conditions (Juglans nigra) and two recalcitrant seeded species (Aesculus hippocastanum and A. glabra) that were stored 11-23 years in LN. Viability of J. nigra axes did not decrease significantly after 23 years and produced normal-appearing plantlets. Similarly, viability of A. hippocastanum axes did not decrease after 23 years. However, A. glabra axes showed a significant decline in viability after 23 years, from 80% when freshly harvested to 33%. These results demonstrate that LN storage can preserve embryo axes of J. nigra and Aesculus sp. for over two decades, providing a workable conservation tool for these and similar species.
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Affiliation(s)
- Daniel Ballesteros
- Center for Research of Endangered Wildlife (CREW), Cincinnati Zoo and Botanical Garden, 3400 Vine Street, Cincinnati, OH, 45220, USA.
| | - Valerie C Pence
- Center for Research of Endangered Wildlife (CREW), Cincinnati Zoo and Botanical Garden, 3400 Vine Street, Cincinnati, OH, 45220, USA
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15
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16
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Romero-Rodríguez MC, Archidona-Yuste A, Abril N, Gil-Serrano AM, Meijón M, Jorrín-Novo JV. Germination and Early Seedling Development in Quercus ilex Recalcitrant and Non-dormant Seeds: Targeted Transcriptional, Hormonal, and Sugar Analysis. FRONTIERS IN PLANT SCIENCE 2018; 9:1508. [PMID: 30405659 PMCID: PMC6204751 DOI: 10.3389/fpls.2018.01508] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 09/26/2018] [Indexed: 05/15/2023]
Abstract
Seed germination and early seedling development have been studied in the recalcitrant species Quercus ilex using targeted transcriptional, hormonal, and sugar analysis. Embryos and seedlings were collected at eight morphologically defined developmental stages, S0-S7. A typical triphasic water uptake curve was observed throughout development, accompanied by a decrease in sucrose and an increase in glucose and fructose. Low levels of abscisic acid (ABA) and high levels of gibberellins (GAs) were observed in mature seeds. Post-germination, indole-3-acetic acid (IAA), increased, whereas GA remained high, a pattern commonly observed during growth and development. The abundance of transcripts from ABA-related genes was positively correlated with the changes in the content of the phytohormone. Transcripts of the drought-related genes Dhn3 and GolS were more abundant at S0, then decreased in parallel with increasing water content. Transcripts for Gapdh, and Nadh6 were abundant at S0, supporting the occurrence of an active metabolism in recalcitrant seeds at the time of shedding. The importance of ROS during germination is manifest in the high transcript levels for Sod and Gst, found in mature seeds. The results presented herein help distinguish recalcitrant (e.g., Q. ilex) seeds from their orthodox counterparts. Our results indicate that recalcitrance is established during seed development but not manifest until germination (S1-S3). Post-germination the patterns are quite similar for both orthodox and recalcitrant seeds.
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Affiliation(s)
- M. Cristina Romero-Rodríguez
- Department of Biochemistry and Molecular Biology, Agrifood Campus of International Excellence, University of Córdoba, Córdoba, Spain
- Departamento de Química Biológica, Dirección de Investigación, Facultad de Ciencias Químicas, Universidad Nacional de Asunción, San Lorenzo, Paraguay
- Centro Multidisciplinario de Investigaciones Tecnológicas, Dirección General de Investigación Científica y Tecnológica, Universidad Nacional de Asunción, San Lorenzo, Paraguay
| | - Antonio Archidona-Yuste
- Department of Biochemistry and Molecular Biology, Agrifood Campus of International Excellence, University of Córdoba, Córdoba, Spain
- Instituto de Agricultura Sostenible, Consejo Superior de Investigaciones Científicas, Campus de Excelencia Internacional Agroalimentario, Córdoba, Spain
| | - Nieves Abril
- Department of Biochemistry and Molecular Biology, Agrifood Campus of International Excellence, University of Córdoba, Córdoba, Spain
| | - Antonio M. Gil-Serrano
- Departamento de Química Orgánica, Facultad de Química, Universidad de Sevilla, Seville, Spain
| | - Mónica Meijón
- Plant Physiology Lab, Department of Organisms and Systems Biology, Faculty of Biology, University of Oviedo, Oviedo, Spain
| | - Jesús V. Jorrín-Novo
- Department of Biochemistry and Molecular Biology, Agrifood Campus of International Excellence, University of Córdoba, Córdoba, Spain
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17
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Singh SP, Phartyal SS, Rosbakh S. Tree seed traits' response to monsoon climate and altitude in Indian subcontinent with particular reference to the Himalayas. Ecol Evol 2017; 7:7408-7419. [PMID: 28944026 PMCID: PMC5606906 DOI: 10.1002/ece3.3181] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 05/11/2017] [Accepted: 05/26/2017] [Indexed: 11/08/2022] Open
Abstract
Seed traits are related to several ecological attributes of a plant species, including its distribution. While the storage physiology of desiccation-sensitive seeds has drawn considerable attention, their ecology has remained sidelined, particularly how the strong seasonality of precipitation in monsoonal climate affects their temporal and spatial distribution. We compiled data on seed mass, seed desiccation behavior, seed shedding, and germination periodicity in relation to monsoon and altitude for 198 native tree species of Indian Himalayas and adjoining plains to find out (1) the adaptive significance of seed mass and seed desiccation behavior in relation to monsoon and (2) the pattern of change in seed mass in relation to altitude, habitat moisture, and succession. The tree species fall into three categories with respect to seed shedding and germination periodicities: (1) species in which both seed shedding and germination are synchronized with monsoon, referred to as monsoon-synchronized (MS, 46 species); (2) species in which seed germination is synchronized with monsoon, but seeds are shed several months before monsoon, referred to as partially monsoon-synchronized (PMS, 112 species); and (3) species in which both shedding and germination occur outside of monsoon months, referred to as monsoon-desynchronized (MD, 39 species). The seed mass of MS species (1,718 mg/seed) was greater than that of PMS (627 mg/seed) and MD (1,144 mg/seed). Of the 40 species with desiccation-sensitive seeds, 45% belong to the MS category, almost similar (approx. 47%) to woody plants with desiccation-sensitive seeds in evergreen rain forests. Seed mass differed significantly as per seed desiccation behavior and successional stage. No relationship of seed mass was found with altitude alone and on the basis of seed desiccation behavior. However, seed mass trend along the altitude differed among monsoon synchronization strategies. Based on our findings, we conclude that in the predicted climate change (warming and uncertain precipitation pattern) scenario, a delay or prolonged break-spell of monsoon may adversely affect the regeneration ecology of desiccation-sensitive seed-bearing species dominant over large forest areas of monsoonal climate.
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Affiliation(s)
- Surendra P. Singh
- Central Himalayan Environment Association (CHEA)06 Waldorf CompoundNainitalUttarakhandIndia
| | - Shyam S. Phartyal
- Department of Forestry and Natural ResourceHNB Garhwal UniversitySrinagar‐GarhwalUttarakhandIndia
| | - Sergey Rosbakh
- Chair of Ecology and Conservation BiologyUniversity of RegensburgRegensburgGermany
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18
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Pritchard H, Nadarajan J, Ballesteros D, Thammasiri K, Prasongsom S, Malik S, Chaudhury R, Kim HH, Lin L, Li WQ, Yang XY, Popova E. Cryobiotechnology of tropical seeds – scale, scope and hope. ACTA HORTICULTURAE 2017:37-48. [DOI: 10.17660/actahortic.2017.1167.6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
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19
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Obroucheva N, Sinkevich I, Lityagina S. Physiological aspects of seed recalcitrance: a case study on the tree Aesculus hippocastanum. TREE PHYSIOLOGY 2016; 36:1127-1150. [PMID: 27259638 DOI: 10.1093/treephys/tpw037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 04/03/2016] [Indexed: 06/05/2023]
Abstract
Recalcitrant seeds are typical of some tropical and subtropical trees. Their post-shedding life activity proceeds in humid air and wet litter. They are desiccation sensitive and, for this reason, have a short life span and need some special procedures for cryopreservation. This review is devoted to the post-shedding life strategy of recalcitrant seeds, which includes the maintenance of high hydration status, metabolic readiness and ability to rapidly germinate before desiccation-induced damage exerts a lethal effect. The main physiological aspects of recalcitrant seeds are considered starting from mature seeds, followed during dormancy if occurs and resulting in germination. The collected data embrace the metabolic processes in embryonic axes and whole seeds. The up-to-date results are integrated covering the main metabolic processes, namely water status and transport, protein and carbohydrate metabolism, antioxidant defense, axis-cotyledon relations, hormonal control and germination. Among the representatives of various taxa, the seeds of which exhibit recalcitrance, attention was given to horse chestnut seeds as one of most studied recalcitrants.
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Affiliation(s)
- Natalie Obroucheva
- Institute of Plant Physiology of Russian Academy of Sciences, Botanicheskaya str. 35, Moscow 127276, Russia
| | - Irina Sinkevich
- Institute of Plant Physiology of Russian Academy of Sciences, Botanicheskaya str. 35, Moscow 127276, Russia
| | - Snejana Lityagina
- Institute of Plant Physiology of Russian Academy of Sciences, Botanicheskaya str. 35, Moscow 127276, Russia
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20
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Walters C. Orthodoxy, recalcitrance and in-between: describing variation in seed storage characteristics using threshold responses to water loss. PLANTA 2015; 242:397-406. [PMID: 25985842 DOI: 10.1007/s00425-015-2312-6] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 04/20/2015] [Indexed: 05/15/2023]
Abstract
Discrete categories of seed physiology can be explained through a unified concept of the structural and molecular mobility responses within cells to drying. Tolerance of desiccation is typically described by a threshold or low water content limit to survival. This convention provides fairly good distinction between orthodox and recalcitrant seeds, which show thresholds of less than about 0.07 and greater than about 0.2 g H2O g DW(-1), respectively. Threshold water contents, however, are not direct measures of the intensity of water stress tolerated by seeds, nor are they measures of cell response to water stress. More direct criteria, that accommodate both spatial and temporal effects of water loss, are required to explain variation of desiccation tolerance and longevity in seeds from diverse genetic backgrounds and growth conditions. This essay presents the argument that changes in cellular volume directly quantify primary responses to desiccating stress in a context that also links damage, as cellular constituents compress, and protection, as compressed molecules form stabilizing structure. During desiccation, fluid cytoplasm solidifies, and the newly formed spatial relationships among molecules determine whether and how long viability is maintained. The diversity of seed behaviors suggests complexity and opportunity to discover molecules and mechanisms that regulate survival and perception of time in cells that lack metabolic function.
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Affiliation(s)
- Christina Walters
- USDA-ARS, National Center for Genetic Resources Preservation, 1111 South Mason Street, Fort Collins, CO, 80521, USA,
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