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Hassani SB, Trontin JF, Raschke J, Zoglauer K, Rupps A. Constitutive Overexpression of a Conifer WOX2 Homolog Affects Somatic Embryo Development in Pinus pinaster and Promotes Somatic Embryogenesis and Organogenesis in Arabidopsis Seedlings. FRONTIERS IN PLANT SCIENCE 2022; 13:838421. [PMID: 35360299 PMCID: PMC8960953 DOI: 10.3389/fpls.2022.838421] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
Although full sequence data of several embryogenesis-related genes are available in conifers, their functions are still poorly understood. In this study, we focused on the transcription factor WUSCHEL-related HOMEOBOX 2 (WOX2), which is involved in determination of the apical domain during early embryogenesis, and is required for initiation of the stem cell program in the embryogenic shoot meristem of Arabidopsis. We studied the effects of constitutive overexpression of Pinus pinaster WOX2 (PpWOX2) by Agrobacterium-mediated transformation of P. pinaster somatic embryos and Arabidopsis seedlings. Overexpression of PpWOX2 during proliferation and maturation of somatic embryos of P. pinaster led to alterations in the quantity and quality of cotyledonary embryos. In addition, transgenic somatic seedlings of P. pinaster showed non-embryogenic callus formation in the region of roots and subsequently inhibited root growth. Overexpression of PpWOX2 in Arabidopsis promoted somatic embryogenesis and organogenesis in a part of the transgenic seedlings of the first and second generations. A concomitant increased expression of endogenous embryogenesis-related genes such as AtLEC1 was detected in transgenic plants of the first generation. Various plant phenotypes observed from single overexpressing transgenic lines of the second generation suggest some significant interactions between PpWOX2 and AtWOX2. As an explanation, functional redundancy in the WOX family is suggested for seed plants. Our results demonstrate that the constitutive high expression of PpWOX2 in Arabidopsis and P. pinaster affected embryogenesis-related traits. These findings further support some evolutionary conserved roles of this gene in embryo development of seed plants and have practical implications toward somatic embryogenesis induction in conifers.
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Affiliation(s)
- Seyedeh Batool Hassani
- Department of Plant Systematics and Evolution, Institute of Biology, Humboldt-Universität zu Berlin, Berlin, Germany
| | | | - Juliane Raschke
- Department of Plant Systematics and Evolution, Institute of Biology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Kurt Zoglauer
- Department of Plant Systematics and Evolution, Institute of Biology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Andrea Rupps
- Department of Plant Systematics and Evolution, Institute of Biology, Humboldt-Universität zu Berlin, Berlin, Germany
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Nunes S, Santos C, Moutinho-Pereira J, Correia C, Oliveira H, Ferreira de Oliveira JM, Pereira VT, Almeida T, Marum L, Dias MC. Physiological characterization and true-to-typeness evaluation of in vitro and ex vitro seedlings of Pinus elliottii: A contribution to breeding programs. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2016; 107:222-227. [PMID: 27314516 DOI: 10.1016/j.plaphy.2016.05.039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 05/30/2016] [Accepted: 05/30/2016] [Indexed: 06/06/2023]
Abstract
Pinus elliottii var. elliottii is a pine species with enormous economic value particularly for timber and resin industries, and is subject of high pressure for genetic improvement and cloning elite genotypes. We have recently developed a robust micropropagation protocol for this species. Plantlets performance needs to be evaluated to validate this protocol for further mass propagation. Micropropagated plantlets and seed-derived plants with similar age and shoot length were compared regarding photosynthesis, carbohydrates and pigments content, water status, DNA content and cell cycle dynamics. Micropropagated plantlets had an overall physiological performance similar to seed-derived plants. In particular, except for the transpiration rate (E), CO2 assimilation rate (A) and total soluble sugars (TSS) content, no major differences between plantlets and seedlings in terms of relative water content (RWC), chlorophyll a fluorescence and pigments content were found. Genetic fidelity analyses support that the micropropagation protocol neither induce DNA content changes nor alterations in cell cycle dynamics.
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Affiliation(s)
- Sandra Nunes
- KLÓN - Innovative Technologies from Cloning, S.A., Cantanhede, Portugal
| | - Conceição Santos
- Department of Biology & GreenUP, CITAB UP, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal.
| | - José Moutinho-Pereira
- Department of Biology and Environment, Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, 5000-801, Vila Real, Portugal
| | - Carlos Correia
- Centre for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193, Aveiro, Portugal
| | - Helena Oliveira
- Centre for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193, Aveiro, Portugal; Department of Chemistry and CICECO, University of Aveiro, 3810-193, Aveiro, Portugal
| | - José Miguel Ferreira de Oliveira
- Department of Biology & GreenUP, CITAB UP, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal; Centre for Environmental and Marine Studies (CESAM), University of Aveiro, 3810-193, Aveiro, Portugal
| | | | - Tânia Almeida
- KLÓN - Innovative Technologies from Cloning, S.A., Cantanhede, Portugal
| | - Liliana Marum
- KLÓN - Innovative Technologies from Cloning, S.A., Cantanhede, Portugal
| | - Maria Celeste Dias
- Centre for Functional Ecology (CEF), Department of Life Science, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal; Department of Chemistry and QOPNA, University of Aveiro, 3810-193, Aveiro, Portugal
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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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