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Hu J, Zhu T, Yao C, Hao C, Yan H, Pu Z, Ma W, Gao B, Gao H, Kong L, Zhang H, Wang J. PaMYB11 promotes suberin deposition in Norway spruce embryogenic tissue during cryopreservation: A novel resistance mechanism against osmosis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 119:2199-2216. [PMID: 38990506 DOI: 10.1111/tpj.16912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 06/13/2024] [Accepted: 06/18/2024] [Indexed: 07/12/2024]
Abstract
The osmotic resistance mechanism has been extensively studied in whole plants or plant tissues. However, little is known about it in embryogenic tissue (ET) which is widely used in plant-based biotechnological systems. Suberin, a cell wall aliphatic and aromatic heteropolymer, plays a critical role in plant cells against osmosis stress. The suberin regulatory biosynthesis has rarely been studied in gymnosperms. Here, PaMYB11, a subgroup 11 R2R3-MYB transcription factor, plays a key role in the osmotic resistance of Norway spruce (Picea abies) ETs during cryoprotectant pretreatment. Thus, RNA-seq, histological, and analytical chemical analyses are performed on the stable transformations of PaMYB11-OE and PaMYB11-SRDX in Norway spruce ETs. DAP-seq, Y1H, and LUC are further combined to explore the PaMYB11 targets. Activation of PaMYB11 is necessary and sufficient for suberin lamellae deposition on Norway spruce embryogenic cell walls, which plays a decisive role in ET survival under osmotic stress. Transcriptome analysis shows that PaMYB11 enhances suberin lamellae monomer synthesis by promoting very long-chain fatty acid (VLCFA) synthesis. PaPOP, PaADH1, and PaTET8L, the first two (PaADH1 and PaPOP, included) involved in VLCFA synthesis, are proved to be the direct targets of PaMYB11. Our study identified a novel osmotic response directed by PaMYB11 in Norway spruce ET, which provides a new understanding of the resistance mechanism against osmosis in gymnosperms.
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Affiliation(s)
- Jiwen Hu
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Tianqing Zhu
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, 100091, China
| | - Chengcheng Yao
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Chunhui Hao
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Huiling Yan
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Ziyan Pu
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Wenjun Ma
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
| | - Benwang Gao
- Management Office of Three Gorges Botanical Garden, Yichang, Hubei, 443111, China
| | - Han Gao
- Management Office of Three Gorges Botanical Garden, Yichang, Hubei, 443111, China
| | - Lisheng Kong
- Department of Biology, Centre for Forest Biology, University of Victoria, Victoria, British Columbia, V8P 5C2, Canada
| | - Hanguo Zhang
- State Key Laboratory of Tree Genetics and Breeding (Northeast Forestry University), Harbin, 150040, China
| | - Junhui Wang
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, 100091, China
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Hazubska-Przybył T, Wawrzyniak MK, Obarska A, Salaj T. Cryopreservation of Abies alba × A. numidica and Pinus nigra embryogenic tissues by stepwise dehydration method. PLANT METHODS 2024; 20:10. [PMID: 38233881 PMCID: PMC10795426 DOI: 10.1186/s13007-023-01131-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 12/23/2023] [Indexed: 01/19/2024]
Abstract
BACKGROUND Cryopreservation makes it possible to preserve plant biodiversity for thousands of years in ex situ storage. The stepwise dehydration method is a simple and versatile cryopreservation technique based on the vitrification phenomenon. However, the commonly used dimethyl sulfoxide (DMSO) in this cryopreservation technique is considered harmful for plant material, thus alternative methods are needed to be applied. RESULTS In this study, the possibility of cryopreservation of embryogenic tissues (ETs) of Abies alba x A. numidica and Pinus nigra was investigated. Before freezing, ETs were partially dehydrated in the presence of increasing concentrations of sucrose (from 0.25 to 1.0 M) for 7 days, followed by desiccation of the tissues over silica gel for 2 and 2.5 h, respectively. After these pretreatments, the plant material was frozen in liquid nitrogen (LN; -196 °C). For both coniferous trees the ET survival rate was high and reached 84.4% for A. alba x A. numidica (28 days) and 86.7% for P. nigra (35 days) after recovery of the tissues from liquid nitrogen (LN). The regenerated tissue of A. alba x A. numidica was characterized by more intense growth after storage in LN compared to tissue that had not been cryopreserved (control). The tissue of this tree also undertook relatively rapid growth after thawing from LN. In turn, the ET growth of P. nigra was significantly lower after thawing compared to the other treatment. CONCLUSIONS The present study demonstrated, that the stepwise dehydration method could be successfully applied to the cryostorage of ETs of both studied trees. To the best of our knowledge, this is the first report on ET cryopreservation based on this method for Abies and Pinus genus representatives, which may be the alternative way for efficient, long-term preservation of germplasm in LN.
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Affiliation(s)
- Teresa Hazubska-Przybył
- Department of Developmental Biology, Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035, Kórnik, Poland.
| | - Mikołaj Krzysztof Wawrzyniak
- Department of Developmental Biology, Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035, Kórnik, Poland
| | - Agata Obarska
- Department of Developmental Biology, Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035, Kórnik, Poland
| | - Terezia Salaj
- Institute of Plant Genetics and Biotechnology Plant Science and Biodiversity Centre Slovak Academy of Sciences, Akademicka 2, P.O. Box 39A, Nitra, 950-07, Slovakia
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Ballesteros D, Martínez MT, Sánchez-Romero C, Montalbán IA, Sales E, Moncaleán P, Arrillaga I, Corredoira E. Current status of the cryopreservation of embryogenic material of woody species. FRONTIERS IN PLANT SCIENCE 2024; 14:1337152. [PMID: 38298606 PMCID: PMC10828030 DOI: 10.3389/fpls.2023.1337152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Accepted: 12/28/2023] [Indexed: 02/02/2024]
Abstract
Cryopreservation, or the storage at liquid nitrogen temperatures (-196°C), of embryogenic cells or somatic embryos allows their long-term conservation without loss of their embryogenic capacity. During the last decade, protocols for cryopreservation of embryogenic material of woody species have been increasing in number and importance. However, despite the large experimental evidence proved in thousands of embryogenic lines, the application for the large-scale conservation of embryogenic material in cryobanks is still limited. Cryopreservation facilitates the management of embryogenic lines, reducing costs and time spent on their maintenance, thus limiting the risk of the appearance of somaclonal variation or contamination. Somatic embryogenesis in combination with cryopreservation is especially useful to preserve the juvenility of lines while the corresponding clones are being field-tested. Hence, when tree performance has been evaluated, selected varieties can be propagated from the cryostock. The traditional method of slow cooling or techniques based on vitrification are mostly applied procedures. For example, slow cooling methods are widely applied to conserve embryogenic lines of conifers. Desiccation based procedures, although simpler, have been applied in a smaller number of species. Genetic stability of the cryopreserved material is supported by multiloci PCR-derived markers in most of the assayed species, whereas DNA methylation status assays showed that cryopreservation might induce some changes that were also observed after prolonged subculture of the embryogenic lines. This article reviews the cryopreservation of embryogenic cultures in conifers, fruit species, deciduous forest species and palms, including a description of the different cryopreservation procedures and the analysis of their genetic stability after storage in liquid nitrogen.
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Affiliation(s)
- Daniel Ballesteros
- Departamento de Botánica y Geología, Facultad de Farmacia, Universitat de València, Burjassot, Valencia, Spain
- Royal Botanic Gardens, Kew, Wakehurst Place, Haywards Heath, United Kingdom
| | - María Teresa Martínez
- Misión Biológica de Galicia (MBG-CSIC), Sede Santiago de Compostela, Santiago de Compostela, Spain
| | | | | | - Ester Sales
- Dpto. Ciencias Agrarias y del Medio natural, Instituto Universitario de Investigación en Ciencias Ambientales (IUCA), Universidad de Zaragoza, Escuela Politécnica Superior, Huesca, Spain
| | | | - Isabel Arrillaga
- Institut Biotec/Med, Dpto Biología Vegetal, Facultad de Farmacia, Universitat de València, Burjassot, Valencia, Spain
| | - Elena Corredoira
- Misión Biológica de Galicia (MBG-CSIC), Sede Santiago de Compostela, Santiago de Compostela, Spain
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Reeves C, Tikkinen M, Aronen T, Krajnakova J. Application of Cold Storage and Short In Vitro Germination for Somatic Embryos of Pinus radiata and P. sylvestris. PLANTS (BASEL, SWITZERLAND) 2023; 12:plants12112095. [PMID: 37299075 DOI: 10.3390/plants12112095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/11/2023] [Accepted: 05/17/2023] [Indexed: 06/12/2023]
Abstract
Somatic embryogenesis (SE) is an advanced vegetative propagation technology that, when used in combination with breeding and cryopreservation, offers the forest industry a powerful tool for the deployment of elite genotypes. Germination and acclimatization are critical and cost-intensive phases in the production of somatic plants. The efficient conversion of somatic embryos into robust plants is a necessity if a propagation protocol is to be successfully adopted by the industry. In this work, these late phases of the SE protocol of two pine species were investigated. A shortened germination protocol and more controlled acclimatization were investigated for Pinus radiata, testing embryos from 18 embryogenic cell lines. A more simplified protocol, including a cold storage phase, was also compared among 10 of these cell lines. A shortened germination period and more controlled protocols significantly improved the acclimatization of somatic embryos directly from the lab to the glasshouse. When results for all cell lines were pooled, there were significant improvements in all growth characteristics (shoot height, root length, root collar diameter, and root quadrant score). When the more simplified protocol involving cold storage was tested, improvements were seen in the root architecture. For Pinus sylvestris, the late phases of somatic embryogenesis were investigated on seven cell lines in a set of two trials (four to seven cell lines per trial). During the germination phase, a shortened and simplified in vitro period, a cold storage option and basal media were explored. Viable plants were obtained from all treatments. However, there is still the need to improve germination and related protocols together with growing regimes for Pinus sylvestris. The improvements to protocols presented here, particularly for Pinus radiata, result in greater survival and quality of somatic emblings, leading to reduced costs and increased confidence in the technology. Simplified protocols using a cold storage option show great promise and, with some further research, could lead to reductions in the cost of the technology.
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Affiliation(s)
- Cathie Reeves
- Scion, Te Papa Tipu Innovation Park, 49 Sala Street, Private Bag 3020, Rotorua 3046, New Zealand
| | - Mikko Tikkinen
- Natural Resources Institute Finland (Luke), FI-57200 Savonlinna, Finland
| | - Tuija Aronen
- Natural Resources Institute Finland (Luke), FI-57200 Savonlinna, Finland
| | - Jana Krajnakova
- Scion, Te Papa Tipu Innovation Park, 49 Sala Street, Private Bag 3020, Rotorua 3046, New Zealand
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Varis SA, Virta S, Montalbán IA, Aronen T. Reducing Pre- and Post-Treatments in Cryopreservation Protocol and Testing Storage at -80 °C for Norway Spruce Embryogenic Cultures. Int J Mol Sci 2022; 23:ijms232415516. [PMID: 36555157 PMCID: PMC9779070 DOI: 10.3390/ijms232415516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/25/2022] [Accepted: 12/03/2022] [Indexed: 12/13/2022] Open
Abstract
Somatic embryogenesis (SE) is considered the most effective method for vegetative propagation of Norway spruce (Picea abies L. Karst). For mass propagation, a storage method that is able to handle large quantities of embryogenic tissues (ETs) reliably and at a low cost is required. The aim of the present study was to compare freezing at -80 °C in a freezer to cryopreservation using liquid nitrogen (LN) as a method for storing Norway spruce ETs. The possibility of simplifying both the pre-treatment and thawing processes in cryopreservation was also studied. The addition of abscisic acid (ABA) to the pre-treatment media and using polyethylene glycol PEG4000 instead of PEG6000 in a cryoprotectant solution were tested. Both the pre-and post-treatments on semi-solid media could be simplified by reducing the number of media, without any loss of genotype or embryo production capacity of ETs. On the contrary, the storage of ETs in a freezer at -80 °C instead of using LN was not possible, and the addition of ABA to the pre-treatment media did not provide benefits but increased costs. The lower regeneration rate after using PEG4000 instead of PEG6000 in a cryoprotectant solution in cryovials was unexpected and unwanted. The simplified pre-and post-treatment protocol will remarkably reduce the workload and costs in the mass-cryopreservation of future forest regeneration materials and in thawing the samples for mass propagations, respectively.
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Affiliation(s)
- Saila A. Varis
- Natural Resources Institute Finland (Luke), Vipusenkuja 5, FI-57200 Savonlinna, Finland
- Correspondence: (S.A.V.); (T.A.)
| | - Susanna Virta
- Natural Resources Institute Finland (Luke), Vipusenkuja 5, FI-57200 Savonlinna, Finland
| | | | - Tuija Aronen
- Natural Resources Institute Finland (Luke), Vipusenkuja 5, FI-57200 Savonlinna, Finland
- Correspondence: (S.A.V.); (T.A.)
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Välimäki S, Teyssier C, Tikkinen M, Delile A, Boizot N, Varis S, Lelu-Walter MA, Aronen T. Norway spruce somatic embryogenesis benefits from proliferation of embryogenic tissues on filter discs and cold storage of cotyledonary embryos. FRONTIERS IN PLANT SCIENCE 2022; 13:1031686. [PMID: 36388484 PMCID: PMC9647157 DOI: 10.3389/fpls.2022.1031686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/07/2022] [Indexed: 06/12/2023]
Abstract
Vegetative propagation opens opportunities for the multiplication of elite tree progeny for forest regeneration material. For conifers such as Norway spruce (Picea abies) the most efficient vegetative propagation method is seed multiplication through somatic embryogenesis. Efficient culture methods are needed for somatic embryogenesis to be commercially viable. Compared to culturing as clumps, filter disc cultures can improve the proliferation of embryogenic tissue (ET) due to more even spread and better developmental synchronization. In this study, ET proliferation on filter discs was compared to proliferation as clumps. The study comprised 28 genotypes in four trials. The benefits of adding a pre-maturation step and the selection of fresh ET for the subculture were evaluated. Pre-maturation on hormone-free media before maturation did not significantly improve embryo yield but improved greenhouse survival from 69% to 80%, although there was high variation between lines. Filter disc cultivation of ET did result in better growth than in clumps but was more dependent on ET selection and the amount of ET than the clump cultivation method. Filter proliferation also favors certain lines. Post-maturation storage can be used to change the storage compound composition of the produced mature embryos. The embryo storage compound profile was analyzed after post-maturation cold storage treatments of 0, 4, 8, 31, and 61 weeks and compared to that of the zygotic embryos. Cold storage made the storage compound profile of somatic embryos closer to that of zygotic embryos, especially regarding the raffinose family oligosaccharides and storage proteins. Sucrose, hexose, and starch content remained higher in somatic embryos even through cold storage. Prolonged storage appeared less beneficial for embryos, some of which then seemed to spontaneously enter the germination process.
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Affiliation(s)
- Sakari Välimäki
- Production Systems, Natural Resources Institute Finland (Luke), Savonlinna, Finland
| | - Caroline Teyssier
- Institut national de recherche pour Íagriculture, Íalimentation et Íenvironnement (INRAE), Office national des forê ts (ONF), BioForA, Orléans, France
| | - Mikko Tikkinen
- Production Systems, Natural Resources Institute Finland (Luke), Savonlinna, Finland
| | - Armelle Delile
- Institut national de recherche pour Íagriculture, Íalimentation et Íenvironnement (INRAE), Office national des forê ts (ONF), BioForA, Orléans, France
| | - Nathalie Boizot
- Institut national de recherche pour Íagriculture, Íalimentation et Íenvironnement (INRAE), Office national des forê ts (ONF), BioForA, Orléans, France
| | - Saila Varis
- Production Systems, Natural Resources Institute Finland (Luke), Savonlinna, Finland
| | - Marie-Anne Lelu-Walter
- Institut national de recherche pour Íagriculture, Íalimentation et Íenvironnement (INRAE), Office national des forê ts (ONF), BioForA, Orléans, France
| | - Tuija Aronen
- Production Systems, Natural Resources Institute Finland (Luke), Savonlinna, Finland
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Cryopreservation of Fraxinus mandshurica Rupr. by Using the Slow Cooling Method. FORESTS 2022. [DOI: 10.3390/f13050773] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Cryopreservation is an important method for the excellent long-term preservation of plant germplasm. This study explores an optimal cryopreservation technology for the embryogenic callus of Fraxinus mandshurica to effectively maintain its genetic stability and morphogenesis potential. The optimal cryopreservation conditions were assessed using the embryogenic callus of F. mandshurica as the material, and the slow cooling method was optimized for its cryopreservation. The results indicated that the preculture of embryogenic callus in 0.4 mol·L−1 sorbitol solution for 20 h at room temperature, followed by its cryoprotection in 7.5% dimethyl sulfoxide solution at 0 °C for 90 min, constituted the optimal material treatment method. The freezing tube was placed in a −80 °C refrigerator for 2 h and then quickly put into liquid nitrogen for frozen storage. During thawing, the cryopreservation tube was taken out from liquid nitrogen, directly placed in a water bath at 40 °C for 2 min, and used for culturing on the woody plant media + 0.1 mg·L−1 6-benzyladenine + 0.15 mg·L−1 2, 4-dichlorophenoxyacetic acid. After cryopreservation using the slow cooling method, the highest survival rate of callus cells was 80.82%. The fresh weight reached 1.93 g after 60-day recovery culture. The regeneration rate and the proliferation coefficient of the callus were 100% and 2.79, respectively. The differentiation rate was 56.83%, and the emergence rate was 23.59%. The results provide a scientific basis for the long-term preservation of F. mandshurica germplasm resources.
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Somatic Embryogenesis of Norway Spruce and Scots Pine: Possibility of Application in Modern Forestry. FORESTS 2022. [DOI: 10.3390/f13020155] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Somatic embryogenesis (SE) is an important method for the vegetative propagation of trees. SE is the developmental in vitro process in which embryos are produced from somatic cells. This method can be integrated with other biotechnological techniques, genomic breeding and cryopreservation, which enables commercial-scale sapling production of selected high-yielding genotypes in wood production combined with fast breeding cycles. The SE is potential tool to improve plant stock in comparison with seed orchards. It can be useful for ecologically and economically important species, such as Norway spruce (Picea abies L. Karst.) and Scots pine (Pinus sylvestris L.), ensuring stable production in the era of climate change and biodiversity crisis. In this review, we summarize the current state of research on problems associated with somatic embryogenesis in P. abies and P. sylvestris.
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Light Spectra during Somatic Embryogenesis of Norway Spruce—Impact on Growth, Embryo Productivity, and Embling Survival. FORESTS 2021. [DOI: 10.3390/f12030301] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
For Norway spruce (Picea abies (L.) Karst.) somatic embryogenesis (SE) culture conditions throughout the propagation process affect the final result. Many critical phases can be identified, and all of them cumulatively increase the production costs of SE plants if they cannot be controlled. In order to determine the best lighting protocol for each SE step, Norway spruce embryogenic tissue (ET) was proliferated, and somatic embryos were matured under different light wavelengths, wavelength combinations, and in the dark. Overall, using low-intensity LED lights during proliferation or at the end of maturation had little effect on the growth of ET, embryo productivity, or embryo survival; on the other hand, major negative effects could not be seen. This is beneficial from a practical point of view, indicating no need for lighting or protection of SE cultures from light during their handling in these steps of the propagation process. When somatic embryos were germinated under different spectra, significant differences in embling shoot and root growth, as well as in the survival of the emblings, were found. The best treatment varied between trials, and the genotype of the SE culture was found to have a stronger effect than the light spectrum, indicating that various light spectra and also intensity adjusted using pulse width modulation (PWM) can be successfully applied to the SE germination phase in Norway spruce.
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Aronen T, Virta S, Varis S. Telomere Length in Norway Spruce during Somatic Embryogenesis and Cryopreservation. PLANTS 2021; 10:plants10020416. [PMID: 33672393 PMCID: PMC7926734 DOI: 10.3390/plants10020416] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 02/10/2021] [Accepted: 02/18/2021] [Indexed: 11/30/2022]
Abstract
Telomeres i.e., termini of the eukaryotic chromosomes protect chromosomes during DNA replication. Shortening of telomeres, either due to stress or ageing is related to replicative cellular senescence. There is little information on the effect of biotechnological methods, such as tissue culture via somatic embryogenesis (SE) or cryopreservation on plant telomeres, even if these techniques are widely applied. The aim of the present study was to examine telomeres of Norway spruce (Picea abies (L.) Karst.) during SE initiation, proliferation, embryo maturation, and cryopreservation to reveal potential ageing or stress-related effects that could explain variation observed at SE process. Altogether, 33 genotypes from 25 families were studied. SE initiation containing several stress factors cause telomere shortening in Norway spruce. Following initiation, the telomere length of the embryogenic tissues (ETs) and embryos produced remains unchanged up to one year of culture, with remarkable genotypic variation. Being prolonged in vitro culture can, however, shorten the telomeres and should be avoided. This is achieved by successful cryopreservation treatment preserving telomere length. Somatic embryo production capacity of the ETs was observed to vary a lot not only among the genotypes, but also from one timepoint to another. No connection between embryo production and telomere length was found, so this variation remains unexplained.
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Root Rot Resistance Locus PaLAR3 Is Delivered by Somatic Embryogenesis (SE) Pipeline in Norway Spruce (Picea abies (L.) Karst.). FORESTS 2021. [DOI: 10.3390/f12020193] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Research Highlights: The Norway spruce somatic embryogenesis (SE) pipeline is suitable for multiplication of material with root rot resistance traits. Background and Objectives: Heterobasidion root rot is the economically most severe forest pathogen in Europe, reducing the benefit of planting elite forest material. In this study, the SE-propagation ability of elite Norway spruce material carrying root rot resistance traits was studied. Materials and Methods: We analyzed the presence of the root rot resistance locus PaLAR3B among 80 Finnish progeny-tested Norway spruce plus-trees used for SE-plant production as well as in 241 SE lines (genotypes) derived from them. Seven full-sib families with lines having either AA, AB, or BB genotype for PaLAR3 locus were further studied for their SE-plant propagation ability. Results: The results indicate that 47.5% of the studied elite trees carry the PaLAR3B allele (45% are heterozygous and 2.5% homozygous). The resistance allele was present among the SE lines as expected based on Mendelian segregation and did not interfere with somatic embryo production capacity. All embryos from PaLAR3 genotypes germinated well and emblings were viable in the end of first growing season. However, in three families, PaLAR3B homo- or heterozygotes had 23.2% to 32.1% lower viability compared to their respective hetero- or PaLAR3A homozygotes. Conclusions: There is no trade-off between root rot resistance locus PaLAR3B and somatic embryo production ability, but the allele may interfere with Norway spruce embling establishment.
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Välimäki S, Hazubska-Przybył T, Ratajczak E, Tikkinen M, Varis S, Aronen T. Somatic Embryo Yield and Quality From Norway Spruce Embryogenic Tissue Proliferated in Suspension Culture. FRONTIERS IN PLANT SCIENCE 2021; 12:791549. [PMID: 34987536 PMCID: PMC8721220 DOI: 10.3389/fpls.2021.791549] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 11/23/2021] [Indexed: 05/06/2023]
Abstract
Somatic embryogenesis is being piloted for the commercial production of genetically improved Norway spruce (Picea abies L. Karst) forest regeneration material in Finland. The main challenge to making the process commercially relevant is the dependence on time-consuming and highly skilled manual labor. Automation and scaling up are needed to improve cost-effectiveness. Moving from the proliferation of embryogenic tissue on semisolid media to suspension cultures could improve process scalability. In a series of four experiments (overall, with 20 cell lines, 4-9 per experiment), the suitability of proliferation in suspension culture for Norway spruce somatic embryogenesis was evaluated based on the growth rate, indicators of stress conditions, good-quality cotyledonary embryo yield, and embling survival in a greenhouse. The proliferation rate in suspension was found equal to on semisolid media, but with a remarkable genotypic variation. Embryogenic tissue matured directly without pre-treatments from suspension onto semisolid media produced lower numbers of good-quality embryos than tissue matured from semisolid media. Rinsing the suspension-grown tissue with hormone-free liquid media before maturation improved embryo yield, bringing it closer to that of semisolid-grown tissue. Decreasing 6-benzylaminopurine and 2,4-dichlorophenoxyacetic acid concentrations in suspension proliferation media to 0.5 or 0.1 times those in semisolid media did not affect tissue growth and did not improve embryo production. The hydrogen peroxide (H2O2) content and guaiacol peroxidase activity were elevated in suspension cultures compared with semisolid medium, which had the same plant growth regulator content. In one experiment out of four, the greenhouse survival of germinants was lower when proliferation was carried out in full strength suspension than on semisolid media; in other experiments the survival rates were equal.
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Affiliation(s)
- Sakari Välimäki
- Natural Resources Institute Finland (Luke), Savonlinna, Finland
- *Correspondence: Sakari Välimäki
| | | | | | - Mikko Tikkinen
- Natural Resources Institute Finland (Luke), Savonlinna, Finland
| | - Saila Varis
- Natural Resources Institute Finland (Luke), Savonlinna, Finland
| | - Tuija Aronen
- Natural Resources Institute Finland (Luke), Savonlinna, Finland
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Varis S, Klimaszewska K, Aronen T. Somatic Embryogenesis and Plant Regeneration From Primordial Shoot Explants of Picea abies (L.) H. Karst. Somatic Trees. FRONTIERS IN PLANT SCIENCE 2018; 9:1551. [PMID: 30405679 PMCID: PMC6207908 DOI: 10.3389/fpls.2018.01551] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 10/03/2018] [Indexed: 05/24/2023]
Abstract
The recalcitrance of adult conifer tissues has prevented vegetative propagation of trees with known and desired characteristics. Somatic embryogenesis (SE) initiation protocol, recently developed for white spruce (Picea glauca, Klimaszewska et al., 2011), was applied in order to examine the feasibility, frequency and timing of SE induction from primordial shoots (PS) of Norway spruce (P. abies). In total, 39 genotypes were screened from 2015 to 2017 using 4-6 years old trees of SE origin as explant donors. Two genotypes responded: 11Pa3794 produced six proliferating embryonal mass (EM) sublines and 11Pa4066 produced 23 EM sublines. SE initiations occurred at the beginning of April, when the temperature sum (d.d.) started to accumulate, and at the end of October or beginning of November when the chilling unit (ch.u.) sum was over 500. EM sublines from both genotypes contained numerous early somatic embryos as detected by acetocarmine staining. The sublines of 11Pa4066 produced the mean of 78.6 ± 12.8 cotyledonary somatic embryos /g FW, but 11Pa3794 produced only a few cotyledonary somatic embryos that were able to germinate. The original EM lines (from which the trees were regenerated) had produced the same number of somatic embryos in 2011 maturations, which was approximately 120 somatic embryos /g FW. Microsatellite analyses conducted with both responsive genotypes confirmed the genetic stability of the EM sublines compared with the donor trees growing in the field. SE protocol developed for white spruce PS explants was also suitable for PS of Norway spruce if the explants were in the responsive developmental stage.
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Affiliation(s)
- Saila Varis
- Natural Resources Institute Finland (Luke), Savonlinna, Finland
| | - Krystyna Klimaszewska
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Quebec, QC, Canada
| | - Tuija Aronen
- Natural Resources Institute Finland (Luke), Savonlinna, Finland
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Development of Somatic Embryo Maturation and Growing Techniques of Norway Spruce Emblings towards Large-Scale Field Testing. FORESTS 2018. [DOI: 10.3390/f9060325] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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