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Bueno N, Cuesta C, Centeno ML, Ordás RJ, Alvarez JM. In Vitro Plant Regeneration in Conifers: The Role of WOX and KNOX Gene Families. Genes (Basel) 2021; 12:genes12030438. [PMID: 33808690 PMCID: PMC8003479 DOI: 10.3390/genes12030438] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/12/2021] [Accepted: 03/17/2021] [Indexed: 11/16/2022] Open
Abstract
Conifers are a group of woody plants with an enormous economic and ecological importance. Breeding programs are necessary to select superior varieties for planting, but they have many limitations due to the biological characteristics of conifers. Somatic embryogenesis (SE) and de novo organogenesis (DNO) from in vitro cultured tissues are two ways of plant mass propagation that help to overcome this problem. Although both processes are difficult to achieve in conifers, they offer advantages like a great efficiency, the possibilities to cryopreserve the embryogenic lines, and the ability of multiplying adult trees (the main bottleneck in conifer cloning) through DNO. Moreover, SE and DNO represent appropriate experimental systems to study the molecular bases of developmental processes in conifers such as embryogenesis and shoot apical meristem (SAM) establishment. Some of the key genes regulating these processes belong to the WOX and KNOX homeobox gene families, whose function has been widely described in Arabidopsis thaliana. The sequences and roles of these genes in conifers are similar to those found in angiosperms, but some particularities exist, like the presence of WOXX, a gene that putatively participates in the establishment of SAM in somatic embryos and plantlets of Pinus pinaster.
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Affiliation(s)
- Natalia Bueno
- Plant Physiology, Biotechnology Institute of Asturias (IUBA), Department of Organisms and Systems Biology, University of Oviedo, ES-33071 Oviedo, Spain; (N.B.); (C.C.); (R.J.O.)
| | - Candela Cuesta
- Plant Physiology, Biotechnology Institute of Asturias (IUBA), Department of Organisms and Systems Biology, University of Oviedo, ES-33071 Oviedo, Spain; (N.B.); (C.C.); (R.J.O.)
| | - María Luz Centeno
- Plant Physiology, Department of Engineering and Agricultural Sciences, University of León, ES-24071 León, Spain;
| | - Ricardo J. Ordás
- Plant Physiology, Biotechnology Institute of Asturias (IUBA), Department of Organisms and Systems Biology, University of Oviedo, ES-33071 Oviedo, Spain; (N.B.); (C.C.); (R.J.O.)
| | - José M. Alvarez
- Plant Physiology, Biotechnology Institute of Asturias (IUBA), Department of Organisms and Systems Biology, University of Oviedo, ES-33071 Oviedo, Spain; (N.B.); (C.C.); (R.J.O.)
- Correspondence:
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Bueno N, Alvarez JM, Ordás RJ. Characterization of the KNOTTED1-LIKE HOMEOBOX (KNOX) gene family in Pinus pinaster Ait. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2020; 301:110691. [PMID: 33218649 DOI: 10.1016/j.plantsci.2020.110691] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/21/2020] [Accepted: 09/23/2020] [Indexed: 05/27/2023]
Abstract
KNOTTED1-LIKE HOMEOBOX (KNOX) genes are a family of plant-specific homeobox transcription factors with important roles in plant development that have been classified into two subfamilies with differential expression domains and functions. Studies in angiosperms have shown that class I members are related to the maintenance of meristem homeostasis and leaf development, whereas class II members promote differentiation of tissues and organs. However, little is known about its diversification and function in gymnosperms. By combining PCR-based detection and transcriptome data analysis, we identified four class I and two class II KNOX genes in Pinus pinaster. Expression analyses showed that class I members were mainly expressed in meristematic regions and differentiating tissues, with practically no expression in lateral organs, whereas expression of class II members was restricted to lateral organs. Furthermore, overexpression of P. pinaster KNOX genes in Arabidopsis thaliana caused similar phenotypic effects to those described for their angiosperms counterparts. This is the first time to our knowledge that functional analyses of class II members are reported in a conifer species. These results suggest a high conservation of the KNOX gene family throughout seed plants, as the functional differentiation of both subfamilies observed in angiosperms might be partially conserved in gymnosperms.
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Affiliation(s)
- Natalia Bueno
- Instituto Universitario de Biotecnología de Asturias (IUBA), Departamento de Biología de Organismos y Sistemas, Universidad de Oviedo, Spain
| | - José Manuel Alvarez
- Instituto Universitario de Biotecnología de Asturias (IUBA), Departamento de Biología de Organismos y Sistemas, Universidad de Oviedo, Spain.
| | - Ricardo J Ordás
- Instituto Universitario de Biotecnología de Asturias (IUBA), Departamento de Biología de Organismos y Sistemas, Universidad de Oviedo, Spain
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Alvarez JM, Bueno N, Cuesta C, Feito I, Ordás RJ. Hormonal and gene dynamics in de novo shoot meristem formation during adventitious caulogenesis in cotyledons of Pinus pinea. PLANT CELL REPORTS 2020; 39:527-541. [PMID: 31993729 PMCID: PMC7067738 DOI: 10.1007/s00299-020-02508-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 01/08/2020] [Indexed: 06/10/2023]
Abstract
KEY MESSAGE Several members of WOX and KNOX gene families and several plant growth regulators, basically cytokinins and auxins, play a key role during adventitious caulogenesis in the conifer Pinus pinea. Similar to Arabidopsis thaliana, Pinus pinea shoot organogenesis is a multistep process. However, there are key differences between both species, which may alter the underlying physiological and genetic programs. It is unknown if the genic expression models during angiosperm development may be applicable to conifers. In this work, an analysis of the endogenous content of different plant growth regulators and the expression of genes putatively involved in adventitious caulogenesis in P. pinea cotyledons was conducted. A multivariate analysis of both datasets was also realized through partial least squares regression and principal component analysis to obtain an integral vision of the mechanisms involved in caulogenesis in P. pinea. Analyses show that cotyledons cultured in the presence of benzyladenine during long times (2-6 days) cluster separately from the rest of the samples, suggesting that the benzyladenine increase observed during the first hours of culture is sufficient to trigger the caulogenic response through the activation of specific developmental programs. In particular, the most relevant factors involved in this process are the cytokinins trans-zeatin, dihydrozeatin, trans-zeatin riboside and isopentenyl adenosine; the auxin indoleacetic acid; and the genes PpWUS, PpWOX5, PpKN2, PpKN3 and PipiRR1. WUS is functional in pines and has an important role in caulogenesis. Interestingly, WOX5 also seems to participate in the process, although its specific role has not been determined.
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Affiliation(s)
- José M Alvarez
- Instituto Universitario de Biotecnología de Asturias, Departamento de Biología de Organismos y Sistemas, Universidad de Oviedo, Oviedo, Spain
| | - Natalia Bueno
- Instituto Universitario de Biotecnología de Asturias, Departamento de Biología de Organismos y Sistemas, Universidad de Oviedo, Oviedo, Spain
| | - Candela Cuesta
- Instituto Universitario de Biotecnología de Asturias, Departamento de Biología de Organismos y Sistemas, Universidad de Oviedo, Oviedo, Spain
| | - Isabel Feito
- Servicio Regional de Investigación Y Desarrollo Agroalimentario de Asturias (SERIDA), Villaviciosa, Spain
| | - Ricardo J Ordás
- Instituto Universitario de Biotecnología de Asturias, Departamento de Biología de Organismos y Sistemas, Universidad de Oviedo, Oviedo, Spain.
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Dalman K, Wind JJ, Nemesio-Gorriz M, Hammerbacher A, Lundén K, Ezcurra I, Elfstrand M. Overexpression of PaNAC03, a stress induced NAC gene family transcription factor in Norway spruce leads to reduced flavonol biosynthesis and aberrant embryo development. BMC PLANT BIOLOGY 2017; 17:6. [PMID: 28061815 PMCID: PMC5219727 DOI: 10.1186/s12870-016-0952-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Accepted: 12/15/2016] [Indexed: 05/20/2023]
Abstract
BACKGROUND The NAC family of transcription factors is one of the largest gene families of transcription factors in plants and the conifer NAC gene family is at least as large, or possibly larger, as in Arabidopsis. These transcription factors control both developmental and stress induced processes in plants. Yet, conifer NACs controlling stress induced processes has received relatively little attention. This study investigates NAC family transcription factors involved in the responses to the pathogen Heterobasidion annosum (Fr.) Bref. sensu lato. RESULTS The phylogeny and domain structure in the NAC proteins can be used to organize functional specificities, several well characterized stress-related NAC proteins are found in III-3 in Arabidopsis (Jensen et al. Biochem J 426:183-196, 2010). The Norway spruce genome contain seven genes with similarity to subgroup III-3 NACs. Based on the expression pattern PaNAC03 was selected for detailed analyses. Norway spruce lines overexpressing PaNAC03 exhibited aberrant embryo development in response to maturation initiation and 482 misregulated genes were identified in proliferating cultures. Three key genes in the flavonoid biosynthesis pathway: a CHS, a F3'H and PaLAR3 were consistently down regulated in the overexpression lines. In accordance, the overexpression lines showed reduced levels of specific flavonoids, suggesting that PaNAC03 act as a repressor of this pathway, possibly by directly interacting with the promoter of the repressed genes. However, transactivation studies of PaNAC03 and PaLAR3 in Nicotiana benthamiana showed that PaNAC03 activated PaLAR3A, suggesting that PaNAC03 does not act as an independent negative regulator of flavan-3-ol production through direct interaction with the target flavonoid biosynthetic genes. CONCLUSIONS PaNAC03 and its orthologs form a sister group to well characterized stress-related angiosperm NAC genes and at least PaNAC03 is responsive to biotic stress and appear to act in the control of defence associated secondary metabolite production.
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Affiliation(s)
- Kerstin Dalman
- Department of Forest Mycology and Plant Pathology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Uppsala, Sweden
- Department of Chemistry and Biotechnology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Julia Johanna Wind
- KTH Biotechnology, Royal Institute of Technology, AlbaNova University Centre, Stockholm, Sweden
| | - Miguel Nemesio-Gorriz
- Department of Forest Mycology and Plant Pathology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Almuth Hammerbacher
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, Jena, Germany
- Department of Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Karl Lundén
- Department of Forest Mycology and Plant Pathology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ines Ezcurra
- KTH Biotechnology, Royal Institute of Technology, AlbaNova University Centre, Stockholm, Sweden
| | - Malin Elfstrand
- Department of Forest Mycology and Plant Pathology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Uppsala, Sweden
- Department of Forest Mycology and Plant Pathology, SLU, PO. Box 7026, Uppsala, 75007 Sweden
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Trontin JF, Klimaszewska K, Morel A, Hargreaves C, Lelu-Walter MA. Molecular Aspects of Conifer Zygotic and Somatic Embryo Development: A Review of Genome-Wide Approaches and Recent Insights. Methods Mol Biol 2016; 1359:167-207. [PMID: 26619863 DOI: 10.1007/978-1-4939-3061-6_8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Genome-wide profiling (transcriptomics, proteomics, metabolomics) is providing unprecedented opportunities to unravel the complexity of coordinated gene expression during embryo development in trees, especially conifer species harboring "giga-genome." This knowledge should be critical for the efficient delivery of improved varieties through seeds and/or somatic embryos in fluctuating markets and to cope with climate change. We reviewed "omics" as well as targeted gene expression studies during both somatic and zygotic embryo development in conifers and tentatively puzzled over the critical processes and genes involved at the specific developmental and transition stages. Current limitations to the interpretation of these large datasets are going to be lifted through the ongoing development of comprehensive genome resources in conifers. Nevertheless omics already confirmed that master regulators (e.g., transcription and epigenetic factors) play central roles. As in model angiosperms, the molecular regulation from early to late embryogenesis may mainly arise from spatiotemporal modulation of auxin-, gibberellin-, and abscisic acid-mediated responses. Omics also showed the potential for the development of tools to assess the progress of embryo development or to build genotype-independent, predictive models of embryogenesis-specific characteristics.
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Affiliation(s)
- Jean-François Trontin
- FCBA, Pôle Biotechnologie et Sylviculture Avancée, Campus Forêt-Bois de Pierroton, 71 Route d'Arcachon, Cestas, 33610, France.
| | - Krystyna Klimaszewska
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., 10380, Stn. Sainte-Foy, QC, Canada, G1V 4C7
| | - Alexandre Morel
- INRA, UR 0588 Unité Amélioration, Génétique et Physiologie Forestières, 2163 Avenue de la Pomme de Pin, CS 4001, Ardon, Orléans Cedex 2, 45075, France
| | | | - Marie-Anne Lelu-Walter
- INRA, UR 0588 Unité Amélioration, Génétique et Physiologie Forestières, 2163 Avenue de la Pomme de Pin, CS 4001, Ardon, Orléans Cedex 2, 45075, France
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Alvarez JM, Sohlberg J, Engström P, Zhu T, Englund M, Moschou PN, von Arnold S. The WUSCHEL-RELATED HOMEOBOX 3 gene PaWOX3 regulates lateral organ formation in Norway spruce. THE NEW PHYTOLOGIST 2015; 208:1078-88. [PMID: 26115363 PMCID: PMC5034847 DOI: 10.1111/nph.13536] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 05/29/2015] [Indexed: 05/18/2023]
Abstract
In angiosperms, WUSCHEL-RELATED HOMEOBOX 3 (WOX3) genes are required for the recruitment of founder cells from the lateral domains of shoot meristems that form lateral regions of leaves. However, the regulation of the formation of lateral organs in gymnosperms remains unknown. By using somatic embryos of Norway spruce (Picea abies) we have studied the expression and function of PaWOX3 during embryo development. The mRNA abundance of PaWOX3 was determined by quantitative real-time PCR, and the spatial expression of PaWOX3 was analysed by histochemical β-glucuronidase (GUS) assays and in situ mRNA hybridization. To investigate the function of PaWOX3, we analysed how downregulation of PaWOX3 in RNA interference lines affected embryo development and morphology. PaWOX3 was highly expressed in mature embryos at the base of each cotyledon close to the junction between the cotyledons, and in the lateral margins of cotyledons and needles, separating them into an adaxial and an abaxial side. Downregulation of the expression of PaWOX3 caused defects in lateral margin outgrowth in cotyledons and needles, and reduced root elongation. Our data suggest that the WOX3 function in margin outgrowth in lateral organs is conserved among the seed plants, whereas its function in root elongation may be unique to gymnosperms.
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Affiliation(s)
- José M. Alvarez
- Department of Plant BiologyUppsala BioCenterSwedish University of Agricultural Sciences, and the Linnean Center for Plant BiologyPO Box 7080SE‐75007UppsalaSweden
| | - Joel Sohlberg
- Department of Plant BiologyUppsala BioCenterSwedish University of Agricultural Sciences, and the Linnean Center for Plant BiologyPO Box 7080SE‐75007UppsalaSweden
| | - Peter Engström
- Department of Organismal BiologyPhysiological BotanyUppsala University, and the Linnean Center for Plant BiologyPO Box 7080SE‐75007UppsalaSweden
| | - Tianqing Zhu
- Department of Plant BiologyUppsala BioCenterSwedish University of Agricultural Sciences, and the Linnean Center for Plant BiologyPO Box 7080SE‐75007UppsalaSweden
| | - Marie Englund
- Department of Organismal BiologyPhysiological BotanyUppsala University, and the Linnean Center for Plant BiologyPO Box 7080SE‐75007UppsalaSweden
| | - Panagiotis N. Moschou
- Department of Plant BiologyUppsala BioCenterSwedish University of Agricultural Sciences, and the Linnean Center for Plant BiologyPO Box 7080SE‐75007UppsalaSweden
| | - Sara von Arnold
- Department of Plant BiologyUppsala BioCenterSwedish University of Agricultural Sciences, and the Linnean Center for Plant BiologyPO Box 7080SE‐75007UppsalaSweden
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Rodríguez-Sanz H, Solís MT, López MF, Gómez-Cadenas A, Risueño MC, Testillano PS. Auxin Biosynthesis, Accumulation, Action and Transport are Involved in Stress-Induced Microspore Embryogenesis Initiation and Progression in Brassica napus. PLANT & CELL PHYSIOLOGY 2015; 56:1401-17. [PMID: 25907568 DOI: 10.1093/pcp/pcv058] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 04/07/2015] [Indexed: 05/17/2023]
Abstract
Isolated microspores are reprogrammed in vitro by stress, becoming totipotent cells and producing embryos and plants via a process known as microspore embryogenesis. Despite the abundance of data on auxin involvement in plant development and embryogenesis, no data are available regarding the dynamics of auxin concentration, cellular localization and the expression of biosynthesis genes during microspore embryogenesis. This work involved the analysis of auxin concentration and cellular accumulation; expression of TAA1 and NIT2 encoding enzymes of two auxin biosynthetic pathways; expression of the PIN1-like efflux carrier; and the effects of inhibition of auxin transport and action by N-1-naphthylphthalamic acid (NPA) and α-(p-chlorophenoxy) isobutyric acid (PCIB) during Brassica napus microspore embryogenesis. The results indicated de novo auxin synthesis after stress-induced microspore reprogramming and embryogenesis initiation, accompanying the first cell divisions. The progressive increase of auxin concentration during progression of embryogenesis correlated with the expression patterns of TAA1 and NIT2 genes of auxin biosynthetic pathways. Auxin was evenly distributed in early embryos, whereas in heart/torpedo embryos auxin was accumulated in apical and basal embryo regions. Auxin efflux carrier PIN1-like gene expression was induced in early multicellular embryos and increased at the globular/torpedo embryo stages. Inhibition of polar auxin transport (PAT) and action, by NPA and PCIB, impaired embryo development, indicating that PAT and auxin action are required for microspore embryo progression. NPA also modified auxin embryo accumulation patterns. These findings indicate that endogenous auxin biosynthesis, action and polar transport are required in stress-induced microspore reprogramming, embryogenesis initiation and progression.
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Affiliation(s)
- Héctor Rodríguez-Sanz
- Pollen Biotechnology of Crop Plants group, Centro de Investigaciones Biológicas (CIB) CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - María-Teresa Solís
- Pollen Biotechnology of Crop Plants group, Centro de Investigaciones Biológicas (CIB) CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - María-Fernanda López
- Departamento de Ciencias Agrarias y del Medio Natural, Universidad Jaume I, Campus Riu Sec, 12071, Castellón, Spain
| | - Aurelio Gómez-Cadenas
- Departamento de Ciencias Agrarias y del Medio Natural, Universidad Jaume I, Campus Riu Sec, 12071, Castellón, Spain
| | - María C Risueño
- Pollen Biotechnology of Crop Plants group, Centro de Investigaciones Biológicas (CIB) CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Pilar S Testillano
- Pollen Biotechnology of Crop Plants group, Centro de Investigaciones Biológicas (CIB) CSIC, Ramiro de Maeztu 9, 28040 Madrid, Spain
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Garcia-Mendiguren O, Montalbán IA, Stewart D, Moncaleán P, Klimaszewska K, Rutledge RG. Gene expression profiling of shoot-derived calli from adult radiata pine and zygotic embryo-derived embryonal masses. PLoS One 2015; 10:e0128679. [PMID: 26039876 PMCID: PMC4454686 DOI: 10.1371/journal.pone.0128679] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 04/29/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Although somatic embryogenesis has an unprecedented potential for large-scale clonal propagation of conifers, the ability to efficiently induce the embryonal cultures required for somatic embryo production has long been a challenge. Furthermore, because early stage zygotic embryos remain the only responsive explants for pines, it is not possible to clone individual trees from vegetative explants at a commercial scale. This is of particular interest for adult trees because many elite characteristics only become apparent following sexual maturation. FINDINGS Shoot explants collected from adult radiata pine trees were cultured on four induction media differing in plant growth regulator composition, either directly after collection or from in vitro-generated axillary shoots. Six callus lines were selected for microscopic examination, which failed to reveal any embryonal masses (EM). qPCR expression profiling of five of these lines indicated that explant type influenced the absolute level of gene expression, but not the type of genes that were expressed. The analysis, which also included three EM lines induced from immature zygotic embryos, encompassed five categories of genes reflective of metabolic, mitotic and meristematic activity, along with putative markers of embryogenicity. Culture medium was found to have no significant impact on gene expression, although differences specific to the explant's origin were apparent. Expression of transcriptional factors associated with vegetative meristems further suggested that all of the callus lines possessed a substantive vegetative character. Most notable, however, was that they all also expressed a putative embryogenic marker (LEC1). CONCLUSIONS While limited in scope, these results illustrate the utility of expression profiling for characterizing tissues in culture. For example, although the biological significance of LEC1 expression is unclear, it does present the possibility that these callus lines possess some level of embryogenic character. Additionally, expression of vegetative meristem markers is consistent with their vegetative origin, as are differences in expression patterns as compared with EM.
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Affiliation(s)
| | - I. A. Montalbán
- Neiker-Tecnalia, Campus Agroalimentario de Arkaute, Vitoria-Gazteiz, Spain
| | - D. Stewart
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Québec, Canada
| | - P. Moncaleán
- Neiker-Tecnalia, Campus Agroalimentario de Arkaute, Vitoria-Gazteiz, Spain
- * E-mail: (RGR); (PM)
| | - K. Klimaszewska
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Québec, Canada
| | - R. G. Rutledge
- Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, Québec, Canada
- * E-mail: (RGR); (PM)
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Zhu T, Moschou PN, Alvarez JM, Sohlberg JJ, von Arnold S. Wuschel-related homeobox 8/9 is important for proper embryo patterning in the gymnosperm Norway spruce. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:6543-52. [PMID: 25205582 PMCID: PMC4246185 DOI: 10.1093/jxb/eru371] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Proper embryo development is crucial as that is when the primary body axes are established. In Arabidopsis, AtWOX8 and AtWOX9, members of the Wuschel-related homeobox (WOX) gene family, are critical for embryo development. In Norway spruce, PaWOX8/9, which is expressed in embryos, is the homologue of AtWOX8 and AtWOX9. In this work, it is shown that the transcript abundance of PaWOX8/9 is high during early and late embryogeny and that it decreases when the maturation phase starts. To address the function of PaWOX8/9 during embryo development, RNAi lines were established to down-regulate the transcript level of PaWOX8/9, using both constitutive and inducible promoters. Embryos in the PaWOX8/9 RNAi lines show an aberrant morphology caused by disturbed orientation of the cell division plane at the basal part of the embryonal mass during early and late embryogeny. In addition, the transcript level of several key cell-cycle-regulating genes, for example, PaE2FAB-like and PaCYCLIN B-like, are affected in the PaWOX8/9 RNAi lines. Taken together, our results suggest that PaWOX8/9 may perform an evolutionarily conserved function as a regulator of the establishment of the apical-basal embryo pattern.
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Affiliation(s)
- Tianqing Zhu
- Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Center of Plant Biology in Uppsala, PO-Box 7080, SE-75007 Uppsala, Sweden
| | - Panagiotis N Moschou
- Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Center of Plant Biology in Uppsala, PO-Box 7080, SE-75007 Uppsala, Sweden
| | - José M Alvarez
- Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Center of Plant Biology in Uppsala, PO-Box 7080, SE-75007 Uppsala, Sweden
| | - Joel J Sohlberg
- Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Center of Plant Biology in Uppsala, PO-Box 7080, SE-75007 Uppsala, Sweden
| | - Sara von Arnold
- Swedish University of Agricultural Sciences, Department of Plant Biology, Uppsala BioCenter, Linnean Center of Plant Biology in Uppsala, PO-Box 7080, SE-75007 Uppsala, Sweden
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Smertenko A, Bozhkov PV. Somatic embryogenesis: life and death processes during apical-basal patterning. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:1343-60. [PMID: 24622953 DOI: 10.1093/jxb/eru005] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Somatic embryogenesis (SE) is a process of differentiation of cells into a plant bypassing the fusion of gametes. As such, it represents a very powerful tool in biotechnology for propagation of species with a long reproductive cycle or low seed set and production of genetically modified plants with improved traits. SE is also a versatile model to study cellular and molecular mechanisms of plant embryo patterning. The morphology and molecular regulation of SE resemble those of zygotic embryogenesis and begin with establishment of apical-basal asymmetry. The apical domain, the embryo proper, proliferates and eventually gives rise to the plantlet, while the basal part, the embryo suspensor, is terminally differentiated and gradually removed via vacuolar programmed cell death (PCD). This PCD is essential for normal development of the apical domain. Emerging evidence demonstrates that signalling events in the apical and basal domains share homologous components. Here we provide an overview of the main pathways controlling the life and death events during SE.
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Affiliation(s)
- Andrei Smertenko
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA
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11
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The Life and Death Signalling Underlying Cell Fate Determination During Somatic Embryogenesis. PLANT CELL MONOGRAPHS 2014. [DOI: 10.1007/978-3-642-41787-0_5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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de Vega-Bartol JJ, Simões M, Lorenz WW, Rodrigues AS, Alba R, Dean JFD, Miguel CM. Transcriptomic analysis highlights epigenetic and transcriptional regulation during zygotic embryo development of Pinus pinaster. BMC PLANT BIOLOGY 2013; 13:123. [PMID: 23987738 PMCID: PMC3844413 DOI: 10.1186/1471-2229-13-123] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Accepted: 08/24/2013] [Indexed: 05/18/2023]
Abstract
BACKGROUND It is during embryogenesis that the plant body plan is established and the meristems responsible for all post-embryonic growth are specified. The molecular mechanisms governing conifer embryogenesis are still largely unknown. Their elucidation may contribute valuable information to clarify if the distinct features of embryo development in angiosperms and gymnosperms result from differential gene regulation. To address this issue, we have performed the first transcriptomic analysis of zygotic embryo development in a conifer species (Pinus pinaster) focusing our study in particular on regulatory genes playing important roles during plant embryo development, namely epigenetic regulators and transcription factors. RESULTS Microarray analysis of P. pinaster zygotic embryogenesis was performed at five periods of embryo development from early developing to mature embryos. Our results show that most changes in transcript levels occurred in the first and the last embryo stage-to-stage transitions, namely early to pre-cotyledonary embryo and cotyledonary to mature embryo. An analysis of functional categories for genes that were differentially expressed through embryogenesis highlighted several epigenetic regulation mechanisms. While putative orthologs of transcripts associated with mechanisms that target transposable elements and repetitive sequences were strongly expressed in early embryogenesis, PRC2-mediated repression of genes seemed more relevant during late embryogenesis. On the other hand, functions related to sRNA pathways appeared differentially regulated across all stages of embryo development with a prevalence of miRNA functions in mid to late embryogenesis. Identification of putative transcription factor genes differentially regulated between consecutive embryo stages was strongly suggestive of the relevance of auxin responses and regulation of auxin carriers during early embryogenesis. Such responses could be involved in establishing embryo patterning. Later in development, transcripts with homology to genes acting on modulation of auxin flow and determination of adaxial-abaxial polarity were up-regulated, as were putative orthologs of genes required for meristem formation and function as well as establishment of organ boundaries. Comparative analysis with A. thaliana embryogenesis also highlighted genes involved in auxin-mediated responses, as well as epigenetic regulation, indicating highly correlated transcript profiles between the two species. CONCLUSIONS This is the first report of a time-course transcriptomic analysis of zygotic embryogenesis in a conifer. Taken together our results show that epigenetic regulation and transcriptional control related to auxin transport and response are critical during early to mid stages of pine embryogenesis and that important events during embryogenesis seem to be coordinated by putative orthologs of major developmental regulators in angiosperms.
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Affiliation(s)
- José J de Vega-Bartol
- iBET - Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2780-901 Oeiras, Portugal
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Marta Simões
- iBET - Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2780-901 Oeiras, Portugal
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - W Walter Lorenz
- Warnell School of Forestry and Natural Resources, The University of Georgia, Athens, GA 30602, USA
| | - Andreia S Rodrigues
- iBET - Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2780-901 Oeiras, Portugal
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Rob Alba
- Monsanto Company, Mailstop CC4, 700 Chesterfield Parkway West, Chesterfield, MO 63017, USA
| | - Jeffrey F D Dean
- Warnell School of Forestry and Natural Resources, The University of Georgia, Athens, GA 30602, USA
| | - Célia M Miguel
- iBET - Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2780-901 Oeiras, Portugal
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
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Li SG, Li WF, Han SY, Yang WH, Qi LW. Stage-specific regulation of four HD-ZIP III transcription factors during polar pattern formation in Larix leptolepis somatic embryos. Gene 2013; 522:177-83. [DOI: 10.1016/j.gene.2013.03.117] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 03/08/2013] [Accepted: 03/22/2013] [Indexed: 12/01/2022]
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14
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Zhao Y, Thammannagowda S, Staton M, Tang S, Xia X, Yin W, Liang H. An EST dataset for Metasequoia glyptostroboides buds: the first EST resource for molecular genomics studies in Metasequoia. PLANTA 2013; 237:755-770. [PMID: 23117391 DOI: 10.1007/s00425-012-1783-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 10/03/2012] [Indexed: 06/01/2023]
Abstract
The "living fossil" Metasequoia glyptostroboides Hu et Cheng, commonly known as dawn redwood or Chinese redwood, is the only living species in the genus and is valued for its essential oil and crude extracts that have great potential for anti-fungal activity. Despite its paleontological significance and economical value as a rare relict species, genomic resources of Metasequoia are very limited. In order to gain insight into the molecular mechanisms behind the formation of reproductive buds and the transition from vegetative phase to reproductive phase in Metasequoia, we performed sequencing of expressed sequence tags from Metasequoia vegetative buds and female buds. By using the 454 pyrosequencing technology, a total of 1,571,764 high-quality reads were generated, among which 733,128 were from vegetative buds and 775,636 were from female buds. These EST reads were clustered and assembled into 114,124 putative unique transcripts (PUTs) with an average length of 536 bp. The 97,565 PUTs that were at least 100 bp in length were functionally annotated by a similarity search against public databases and assigned with Gene Ontology (GO) terms. A total of 59 known floral gene families and 190 isotigs involved in hormone regulation were captured in the dataset. Furthermore, a set of PUTs differentially expressed in vegetative and reproductive buds, as well as SSR motifs and high confidence SNPs, were identified. This is the first large-scale expressed sequence tags ever generated in Metasequoia and the first evidence for floral genes in this critically endangered deciduous conifer species.
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Affiliation(s)
- Ying Zhao
- College of Biological Sciences and Biotechnology, Beijing Forestry University, No. 35 Tsinghua Eastern Road, Beijing, 100083, People's Republic of China
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15
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Larsson E, Sundström JF, Sitbon F, von Arnold S. Expression of PaNAC01, a Picea abies CUP-SHAPED COTYLEDON orthologue, is regulated by polar auxin transport and associated with differentiation of the shoot apical meristem and formation of separated cotyledons. ANNALS OF BOTANY 2012; 110:923-34. [PMID: 22778149 PMCID: PMC3423809 DOI: 10.1093/aob/mcs151] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 05/15/2012] [Indexed: 05/19/2023]
Abstract
BACKGROUND AND AIMS During embryo development in most gymnosperms, the establishment of the shoot apical meristem (SAM) occurs concomitantly with the formation of a crown of cotyledons surrounding the SAM. It has previously been shown that the differentiation of cotyledons in somatic embryos of Picea abies is dependent on polar auxin transport (PAT). In the angiosperm model plant, Arabidopsis thaliana, the establishment of cotyledonary boundaries and the embryonal SAM is dependent on PAT and the expression of the CUP-SHAPED COTYLEDON (CUC) genes, which belong to the large NAC gene family. The aim of this study was to characterize CUC-like genes in a gymnosperm, and to elucidate their expression during SAM and cotyledon differentiation, and in response to PAT. METHODS Sixteen Picea glauca NAC sequences were identified in GenBank and deployed to different clades within the NAC gene family using maximum parsimony analysis and Bayesian inference. Motifs conserved between angiosperms and gymnosperms were analysed using the motif discovery tool MEME. Expression profiles during embryo development were produced using quantitative real-time PCR. Protein conservation was analysed by introducing a P. abies CUC orthologue into the A. thaliana cuc1cuc2 double mutant. KEY RESULTS Two full-length CUC-like cDNAs denoted PaNAC01 and PaNAC02 were cloned from P. abies. PaNAC01, but not PaNAC02, harbours previously characterized functional motifs in CUC1 and CUC2. The expression profile of PaNAC01 showed that the gene is PAT regulated and associated with SAM differentiation and cotyledon formation. Furthermore, PaNAC01 could functionally substitute for CUC2 in the A. thaliana cuc1cuc2 double mutant. CONCLUSIONS The results show that CUC-like genes with distinct signature motifs existed before the separation of angiosperms and gymnosperms approx. 300 million years ago, and suggest a conserved function between PaNAC01 and CUC1/CUC2.
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Affiliation(s)
- Emma Larsson
- Department of Plant Biology and Forest Genetics, Linnean Centre of Plant Biology in Uppsala, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala, Sweden.
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