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Florez-Rueda AM, Miguel CM, Figueiredo DD. Comparative transcriptomics of seed nourishing tissues: uncovering conserved and divergent pathways in seed plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 119:1134-1157. [PMID: 38709819 DOI: 10.1111/tpj.16786] [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: 10/13/2023] [Revised: 04/04/2024] [Accepted: 04/12/2024] [Indexed: 05/08/2024]
Abstract
The evolutionary and ecological success of spermatophytes is intrinsically linked to the seed habit, which provides a protective environment for the initial development of the new generation. This environment includes an ephemeral nourishing tissue that supports embryo growth. In gymnosperms this tissue originates from the asexual proliferation of the maternal megagametophyte, while in angiosperms it is a product of fertilization, and is called the endosperm. The emergence of these nourishing tissues is of profound evolutionary value, and they are also food staples for most of the world's population. Here, using Orthofinder to infer orthologue genes among newly generated and previously published datasets, we provide a comparative transcriptomic analysis of seed nourishing tissues from species of several angiosperm clades, including those of early diverging lineages, as well as of one gymnosperm. Our results show that, although the structure and composition of seed nourishing tissues has seen significant divergence along evolution, there are signatures that are conserved throughout the phylogeny. Conversely, we identified processes that are specific to species within the clades studied, and thus illustrate their functional divergence. With this, we aimed to provide a foundation for future studies on the evolutionary history of seed nourishing structures, as well as a resource for gene discovery in future functional studies.
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Affiliation(s)
- Ana Marcela Florez-Rueda
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, Am Mühlenberg 1, 14476, Potsdam, Germany
- University of Potsdam, Karl-Liebknechts-Str. 24-25, Haus 26, 14476, Potsdam, Germany
| | - Célia M Miguel
- Faculty of Sciences, Biosystems and Integrative Sciences Institute (BioISI), University of Lisbon, Lisboa, Portugal
| | - Duarte D Figueiredo
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, Am Mühlenberg 1, 14476, Potsdam, Germany
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2
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Cordeiro D, Canhoto J, Correia S. Regulatory non-coding RNAs: Emerging roles during plant cell reprogramming and in vitro regeneration. FRONTIERS IN PLANT SCIENCE 2022; 13:1049631. [PMID: 36438127 PMCID: PMC9684189 DOI: 10.3389/fpls.2022.1049631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 10/25/2022] [Indexed: 06/16/2023]
Abstract
Plant regeneration is a well-known capacity of plants occurring either in vivo or in vitro. This potential is the basis for plant micropropagation and genetic transformation as well as a useful system to analyse different aspects of plant development. Recent studies have proven that RNA species with no protein-coding capacity are key regulators of cellular function and essential for cell reprogramming. In this review, the current knowledge on the role of several ncRNAs in plant regeneration processes is summarized, with a focus on cell fate reprogramming. Moreover, the involvement/impact of microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and small-interfering RNAs (siRNAs) in the regulatory networks of cell dedifferentiation, proliferation and differentiation is also analysed. A deeper understanding of plant ncRNAs in somatic cell reprogramming will allow a better modulation of in vitro regeneration processes such as organogenesis and somatic embryogenesis.
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3
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Xu XP, Cao QY, Guan QX, Mohammadi MA, Di Cai R, Chen XH, Zhang ZH, Chen YK, Xuhan X, Lin YL, Lai ZX. Genome-wide identification of miRNAs and targets associated with cell wall biosynthesis: Differential roles of dlo-miR397a and dlo-miR408-3p during early somatic embryogenesis in longan. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 323:111372. [PMID: 35863557 DOI: 10.1016/j.plantsci.2022.111372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Revised: 06/12/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
The dynamic alterations in cell wall (CW) biosynthesis play an essential role in physiological isolation during the plant somatic embryogenesis (SE). However, the mechanisms underlying the functions of cell wall-associated miRNAs (CW-miRNA) remain poorly understood in plant SE. Here, we have identified 36 distinct candidate miRNAs associated with CW biosynthesis from longan third-generation genome as well as miRNA transcriptome, and modified RLM-RACE validated four distinct miRNA, which specifically targeted four CW-related genes. More importantly, we found that the dlo-miR397a-antagomir significantly enhanced DlLAC7 expression and improved laccase activity. Interestingly, inhibition of dlo-miR397a increased CW lignin deposition and promoted the tightening of protodermal cell by miRNA-mimic technology during early SE. Moreover, overexpression of dlo-miR408-3p (dlo-miR408-3p-agomir) markedly decreased DlLAC12 expression. dlo-miR408-3p-agomir activated rapid cell division, thus promoting the globular embryo (GE) development, which might be due to high DNA synthesis activity in protoepidermal cells, rather than affecting lignin synthesis. The subcellular location also indicated that both DlLAC7 and DlLAC12 proteins were primarily localized in CW and regulated CW biosynthesis. Overall, our findings provided new insight on the molecular regulatory networks comprising various miRNAs associated with cell wall, and established that dlo-miR397a and dlo-miR408-3p played differential roles during early SE in longan. The findings also shed some light on the potential role of miRNA target DlLAC regulating in vivo embryonic development of plant.
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Affiliation(s)
- Xiao Ping Xu
- Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China; Institute of Biotechnology, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian 350003, China
| | - Qing Ying Cao
- Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Qing Xu Guan
- Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Mohammad Aqa Mohammadi
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Rou Di Cai
- Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Xiao Hui Chen
- Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Zi Hao Zhang
- Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Yu Kun Chen
- Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Xu Xuhan
- Institut de la Recherche Interdisciplinaire de Toulouse, IRIT-ARI, 31300 Toulouse, France
| | - Yu Ling Lin
- Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China.
| | - Zhong Xiong Lai
- Institute of Horticultural Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China.
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MicroRNA-mediated post-transcriptional regulation of Pinus pinaster response and resistance to pinewood nematode. Sci Rep 2022; 12:5160. [PMID: 35338210 PMCID: PMC8956650 DOI: 10.1038/s41598-022-09163-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 03/15/2022] [Indexed: 11/16/2022] Open
Abstract
Pine wilt disease (PWD), caused by the parasitic nematode Bursaphelenchus xylophilus, or pinewood nematode (PWN), is a serious threat to pine forests in Europe. Pinus pinaster is highly susceptible to the disease and it is currently the most affected European pine species. In this work, we investigated the role of small RNAs (sRNAs) in regulating P. pinaster–PWN interaction in an early stage of infection. After performing an artificial PWN inoculation assay, we have identified 105 plant microRNAs (miRNAs) responsive to PWN. Based on their predicted targets, part of these miRNAs was associated with roles in jasmonate-response pathway, ROS detoxification, and terpenoid biosynthesis. Furthermore, by comparing resistant and susceptible plants, eight miRNAs with putative functions in plant defence and resistance to PWN have been identified. Finally, we explored the possibility of bidirectional trans-kingdom RNA silencing, identifying several P. pinaster genes putatively targeted by PWN miRNAs, which was supported by degradome analysis. Targets for P. pinaster miRNAs were also predicted in PWN, suggesting a role for trans-kingdom miRNA transfer and gene silencing both in PWN parasitism as in P. pinaster resistance to PWD. Our results provide new insights into previously unexplored roles of sRNA post-transcriptional regulation in P. pinaster response and resistance to PWN.
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Alves A, Confraria A, Lopes S, Costa B, Perdiguero P, Milhinhos A, Baena-González E, Correia S, Miguel CM. miR160 Interacts in vivo With Pinus pinaster AUXIN RESPONSE FACTOR 18 Target Site and Negatively Regulates Its Expression During Conifer Somatic Embryo Development. FRONTIERS IN PLANT SCIENCE 2022; 13:857611. [PMID: 35371172 PMCID: PMC8965291 DOI: 10.3389/fpls.2022.857611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 02/21/2022] [Indexed: 06/14/2023]
Abstract
MicroRNAs (miRNAs) are key regulators of several plant developmental processes including embryogenesis. Most miRNA families are conserved across major groups of plant species, but their regulatory roles have been studied mainly in model species like Arabidopsis and other angiosperms. In gymnosperms, miRNA-dependent regulation has been less studied since functional approaches in these species are often difficult to establish. Given the fundamental roles of auxin signaling in somatic embryogenesis (SE) induction and embryo development, we investigated a previously predicted interaction between miR160 and a putative target encoding AUXIN RESPONSE FACTOR 18 in Pinus pinaster (PpARF18) embryonic tissues. Phylogenetic analysis of AUXIN RESPONSE FACTOR 18 (ARF18) from Pinus pinaster and Picea abies, used here as a model system of conifer embryogenesis, showed their close relatedness to AUXIN RESPONSE FACTOR (ARF) genes known to be targeted by miR160 in other species, including Arabidopsis ARF10 and ARF16. By using a luciferase (LUC) reporter system for miRNA activity in Arabidopsis protoplasts, we have confirmed that P. pinaster miR160 (ppi-miR160) interacts in vivo with PpARF18 target site. When the primary miR160 from P. pinaster was overexpressed in protoplasts under non-limiting levels of ARGONAUTE1, a significant increase of miR160 target cleavage activity was observed. In contrast, co-expression of the primary miRNA and the target mimic MIM160 led to a decrease of miR160 activity. Our results further support that this interaction is functional during consecutive stages of SE in the conifer model P. abies. Expression analyses conducted in five stages of development, from proembryogenic masses (PEMs) to the mature embryo, show that conifer ARF18 is negatively regulated by miR160 toward the fully developed mature embryo when miR160 reached its highest expression level. This study reports the first in vivo validation of a predicted target site of a conifer miRNA supporting the conservation of miR160 interaction with ARF targets in gymnosperms. The approach used here should be useful for future characterization of miRNA functions in conifer embryogenesis.
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Affiliation(s)
- Ana Alves
- Faculty of Sciences, BioISI—Biosystems and Integrative Sciences Institute, University of Lisbon, Lisbon, Portugal
| | - Ana Confraria
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- GREEN-IT Bioresources for Sustainability, ITQB NOVA, Oeiras, Portugal
| | - Susana Lopes
- Faculty of Sciences, BioISI—Biosystems and Integrative Sciences Institute, University of Lisbon, Lisbon, Portugal
- GREEN-IT Bioresources for Sustainability, ITQB NOVA, Oeiras, Portugal
| | - Bruno Costa
- Faculty of Sciences, BioISI—Biosystems and Integrative Sciences Institute, University of Lisbon, Lisbon, Portugal
- INESC-ID, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
| | - Pedro Perdiguero
- Department of Genetics, Physiology and Microbiology, Faculty of Biological Sciences, Complutense University of Madrid (UCM), Madrid, Spain
| | - Ana Milhinhos
- Faculty of Sciences, BioISI—Biosystems and Integrative Sciences Institute, University of Lisbon, Lisbon, Portugal
- GREEN-IT Bioresources for Sustainability, ITQB NOVA, Oeiras, Portugal
| | - Elena Baena-González
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- GREEN-IT Bioresources for Sustainability, ITQB NOVA, Oeiras, Portugal
| | - Sandra Correia
- Department of Life Sciences, Centre for Functional Ecology, University of Coimbra, Coimbra, Portugal
| | - Célia M. Miguel
- Faculty of Sciences, BioISI—Biosystems and Integrative Sciences Institute, University of Lisbon, Lisbon, Portugal
- Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
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miR172 Regulates WUS during Somatic Embryogenesis in Arabidopsis via AP2. Cells 2022; 11:cells11040718. [PMID: 35203367 PMCID: PMC8869827 DOI: 10.3390/cells11040718] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 02/11/2022] [Accepted: 02/15/2022] [Indexed: 02/04/2023] Open
Abstract
In plants, the embryogenic transition of somatic cells requires the reprogramming of the cell transcriptome, which is under the control of genetic and epigenetic factors. Correspondingly, the extensive modulation of genes encoding transcription factors and miRNAs has been indicated as controlling the induction of somatic embryogenesis in Arabidopsis and other plants. Among the MIRNAs that have a differential expression during somatic embryogenesis, members of the MIRNA172 gene family have been identified, which implies a role of miR172 in controlling the embryogenic transition in Arabidopsis. In the present study, we found a disturbed expression of both MIRNA172 and candidate miR172-target genes, including AP2, TOE1, TOE2, TOE3, SMZ and SNZ, that negatively affected the embryogenic response of transgenic explants. Next, we examined the role of AP2 in the miR172-mediated mechanism that controls the embryogenic response. We found some evidence that by controlling AP2, miR172 might repress the WUS that has an important function in embryogenic induction. We showed that the mechanism of the miR172-AP2-controlled repression of WUS involves histone acetylation. We observed the upregulation of the WUS transcripts in an embryogenic culture that was overexpressing AP2 and treated with trichostatin A (TSA), which is an inhibitor of HDAC histone deacetylases. The increased expression of the WUS gene in the embryogenic culture of the hdac mutants further confirmed the role of histone acetylation in WUS control during somatic embryogenesis. A chromatin-immunoprecipitation analysis provided evidence about the contribution of HDA6/19-mediated histone deacetylation to AP2-controlled WUS repression during embryogenic induction. The upstream regulatory elements of the miR172-AP2-WUS pathway might involve the miR156-controlled SPL9/SPL10, which control the level of mature miR172 in an embryogenic culture.
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Lamelas L, Valledor L, López-Hidalgo C, Cañal MJ, Meijón M. Nucleus and chloroplast: A necessary understanding to overcome heat stress in Pinus radiata. PLANT, CELL & ENVIRONMENT 2022; 45:446-458. [PMID: 34855991 DOI: 10.1111/pce.14238] [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: 08/09/2021] [Revised: 11/23/2021] [Accepted: 11/23/2021] [Indexed: 06/13/2023]
Abstract
The recovery and maintenance of plant homeostasis under stressful environments are complex processes involving organelle crosstalk for a coordinated cellular response. Here, we revealed through nuclear and chloroplast subcellular proteomics, biochemical cell profiles and targeted transcriptomics how chloroplasts and nuclei developed their responses under increased temperatures in a long-lived species (Pinus radiata). Parallel to photosynthetic impairment and reactive oxygen species production in the chloroplast, a DNA damage response was triggered in the nucleus followed by an altered chromatin conformation. In addition, in the nuclei, we found several proteins, such as HEMERA or WHIRLY, which change their locations from the chloroplasts to the nuclei carrying the stress message. Additionally, our data showed a deep rearrangement of RNA metabolism in both organelles, revealing microRNAs and AGO1 as potential regulators of the acclimation mechanisms. Altogether, our study highlights the synchronisation among the different stages required for thermotolerance acquisition in P. radiata, pointing out the role of chromatin conformation and posttranscriptional gene regulation in overcoming heat stress and assuring plant survival for the following years.
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Affiliation(s)
- Laura Lamelas
- Plant Physiology, Department of Organisms and Systems Biology, University of Oviedo, Biotechnology Institute of Asturias, Oviedo, Asturias, Spain
| | - Luis Valledor
- Plant Physiology, Department of Organisms and Systems Biology, University of Oviedo, Biotechnology Institute of Asturias, Oviedo, Asturias, Spain
| | - Cristina López-Hidalgo
- Plant Physiology, Department of Organisms and Systems Biology, University of Oviedo, Biotechnology Institute of Asturias, Oviedo, Asturias, Spain
| | - María Jesús Cañal
- Plant Physiology, Department of Organisms and Systems Biology, University of Oviedo, Biotechnology Institute of Asturias, Oviedo, Asturias, Spain
| | - Mónica Meijón
- Plant Physiology, Department of Organisms and Systems Biology, University of Oviedo, Biotechnology Institute of Asturias, Oviedo, Asturias, Spain
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8
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Meijer A, De Meyer T, Vandepoele K, Kyndt T. Spatiotemporal expression profile of novel and known small RNAs throughout rice plant development focussing on seed tissues. BMC Genomics 2022; 23:44. [PMID: 35012466 PMCID: PMC8750796 DOI: 10.1186/s12864-021-08264-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/13/2021] [Indexed: 02/10/2023] Open
Abstract
Background Small RNAs (sRNAs) regulate numerous plant processes directly related to yield, such as disease resistance and plant growth. To exploit this yield-regulating potential of sRNAs, the sRNA profile of one of the world’s most important staple crops – rice – was investigated throughout plant development using next-generation sequencing. Results Root and leaves were investigated at both the vegetative and generative phase, and early-life sRNA expression was characterized in the embryo and endosperm. This led to the identification of 49,505 novel sRNAs and 5581 tRNA-derived sRNAs (tsRNAs). In all tissues, 24 nt small interfering RNAs (siRNAs) were highly expressed and associated with euchromatic, but not heterochromatic transposable elements. Twenty-one nt siRNAs deriving from genic regions in the endosperm were exceptionally highly expressed, mimicking previously reported expression levels of 24 nt siRNAs in younger endosperm samples. In rice embryos, sRNA content was highly diverse while tsRNAs were underrepresented, possibly due to snoRNA activity. Publicly available mRNA expression and DNA methylation profiles were used to identify putative siRNA targets in embryo and endosperm. These include multiple genes related to the plant hormones gibberellic acid and ethylene, and to seed phytoalexin and iron content. Conclusions This work introduces multiple sRNAs as potential regulators of rice yield and quality, identifying them as possible targets for the continuous search to optimize rice production. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-08264-z.
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Affiliation(s)
- Anikó Meijer
- Department of Biotechnology, Ghent University, Ghent, Belgium
| | - Tim De Meyer
- Department of Data Analysis and Mathematical Modelling, Ghent University, Ghent, Belgium
| | - Klaas Vandepoele
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium. .,VIB Center for Plant Systems Biology, Ghent, Belgium. .,Bioinformatics Institute Ghent, Ghent University, Ghent, Belgium.
| | - Tina Kyndt
- Department of Biotechnology, Ghent University, Ghent, Belgium.
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Yan J, Buer H, Wang YP, Zhula G, Bai YE. Transcriptomic Time-Series Analyses of Gene Expression Profile During Zygotic Embryo Development in Picea mongolica. Front Genet 2021; 12:738649. [PMID: 34659359 PMCID: PMC8513737 DOI: 10.3389/fgene.2021.738649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 09/01/2021] [Indexed: 11/13/2022] Open
Abstract
Zygotic embryogenesis is a critical process during seed development in gymnosperms. However, knowledge on the genome-wide transcriptional activation that guides this process in conifers is limited, especially in Picea mongolica. This tree species is endemic to semiarid habitats of Inner Mongolia in China. To extend what is known about the molecular events underpinning its zygotic embryogenesis, comparative transcriptomic analyses of gene expression in zygotic embryos were performed by RNA sequencing in P. mongolica. Our results showed that most changes in transcript levels occurred in the early embryonic pattering determination and formation of mature embryos. Transcripts related to embryogenic competence, cell division pattern, hormones, and stress response genes were identified during embryogenesis. Auxin is essential for early embryo patterning and pre-cotyledon embryonic formation. However, ABA is a major regulator of embryo maturation. Moreover, we found that methylation-related gene expression is associated with activation of early-stage embryos, late embryogenesis abundant proteins, and storage/energy-related genes with late and mature embryos. Furthermore, network analysis revealed stage-specific and multistage gene expression clusters during embryogenesis. WOX, MYB, AP2, and HLH transcription factors seem more relevant to embryogenesis in different stages. Our results provide large-scale and comprehensive transcriptome data for embryo development in P. mongolica. These data will lay a foundation for the protection and utilization of P. mongolica resources.
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Affiliation(s)
- Jia Yan
- Institute of Forest Tree Genetic Breeding, Forestry College, Inner Mongolia Agricultural University, Hohhot, China.,Life Science of College, Inner Mongolia University, Hohhot, China
| | - Ha Buer
- Institute of Forest Tree Genetic Breeding, Forestry College, Inner Mongolia Agricultural University, Hohhot, China
| | - Ya Ping Wang
- Institute of Forest Tree Genetic Breeding, Forestry College, Inner Mongolia Agricultural University, Hohhot, China
| | - Gegen Zhula
- Institute of Forest Tree Genetic Breeding, Forestry College, Inner Mongolia Agricultural University, Hohhot, China
| | - Yu E Bai
- Institute of Forest Tree Genetic Breeding, Forestry College, Inner Mongolia Agricultural University, Hohhot, China
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Zhang Y, Yang J, Zhu L, Xue J, Hu H, Cui J, Xu J. Identification of microRNAs and their target genes related to needle discoloration of evergreen tree Chinese cedar (Cryptomeria fortunei) in cold winters. PLANTA 2021; 254:31. [PMID: 34283297 DOI: 10.1007/s00425-021-03685-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 07/12/2021] [Indexed: 06/13/2023]
Abstract
Comparative analysis of miRNAs and their gene targets between the evergreen and yellowish-brown Cryptomeria fortunei phenotypes in cold winters suggests a possible role of miRNA-regulated pathways in needle color. Cryptomeria fortunei (Chinese cedar) is a conifer tree of considerable economic, ornamental and ecological importance. Despite the evergreen nature of C. fortunei, most needles turn yellowish- or reddish-brown in winter. The roles of microRNAs (miRNAs) in regulating pigment biosynthesis in color-leafed plants have been widely investigated. However, whether or not an miRNA-mediated staged discoloration mechanism exists in evergreen C. fortunei is currently unknown. In this study, we deciphered the microRNAs landscape in overwintering C. fortunei needles using high-throughput sequencing. A total of 517 known and 212 novel miRNA mature/star sequences, including 233 differentially expressed miRNAs, were identified. Based on integrated transcriptome and miRNA analysis, 2702 target unigenes of the miRNAs were predicted and these targets were significantly enriched in pigment-related biosynthesis pathways. A miRNA-target pigment biosynthesis regulatory network was then constructed, and its module miRNA (ath-miR858b, aly-miR858-3p, cme-miR828 and novel33_mature)-MYBs (v-myb avian myeloblastosis viral oncogene homolog) appeared to be a key factor regulating needle discoloration in C. fortunei. These miRNA-MYBs were further confirmed by degradome sequencing. Overall, these findings provide new insight into the posttranscriptional regulatory mechanism of leaf/needle discoloration in gymnosperms and may contribute to the miRNA-mediated genetic improvement of evergreen C. fortunei needles.
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Affiliation(s)
- Yingting Zhang
- Key Laboratory of Forest Genetics and Biotechnology of Ministry of Education, Nanjing Forestry University, Nanjing, 210037, China
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China
- College of Forestry, Nanjing Forestry University, Nanjing, 210037, China
| | - Junjie Yang
- Key Laboratory of Forest Genetics and Biotechnology of Ministry of Education, Nanjing Forestry University, Nanjing, 210037, China
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China
- College of Forestry, Nanjing Forestry University, Nanjing, 210037, China
| | - Lijuan Zhu
- Key Laboratory of Forest Genetics and Biotechnology of Ministry of Education, Nanjing Forestry University, Nanjing, 210037, China
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China
- College of Forestry, Nanjing Forestry University, Nanjing, 210037, China
| | - Jinyu Xue
- Key Laboratory of Forest Genetics and Biotechnology of Ministry of Education, Nanjing Forestry University, Nanjing, 210037, China
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China
- College of Forestry, Nanjing Forestry University, Nanjing, 210037, China
| | - Hailiang Hu
- Key Laboratory of Forest Genetics and Biotechnology of Ministry of Education, Nanjing Forestry University, Nanjing, 210037, China
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China
- College of Forestry, Nanjing Forestry University, Nanjing, 210037, China
| | - Jiebing Cui
- Key Laboratory of Forest Genetics and Biotechnology of Ministry of Education, Nanjing Forestry University, Nanjing, 210037, China
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China
- College of Forestry, Nanjing Forestry University, Nanjing, 210037, China
| | - Jin Xu
- Key Laboratory of Forest Genetics and Biotechnology of Ministry of Education, Nanjing Forestry University, Nanjing, 210037, China.
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China.
- College of Forestry, Nanjing Forestry University, Nanjing, 210037, China.
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11
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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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Alves A, Cordeiro D, Correia S, Miguel C. Small Non-Coding RNAs at the Crossroads of Regulatory Pathways Controlling Somatic Embryogenesis in Seed Plants. PLANTS (BASEL, SWITZERLAND) 2021; 10:504. [PMID: 33803088 PMCID: PMC8001652 DOI: 10.3390/plants10030504] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 02/26/2021] [Accepted: 03/01/2021] [Indexed: 11/25/2022]
Abstract
Small non-coding RNAs (sncRNAs) are molecules with important regulatory functions during development and environmental responses across all groups of terrestrial plants. In seed plants, the development of a mature embryo from the zygote follows a synchronized cell division sequence, and growth and differentiation events regulated by highly regulated gene expression. However, given the distinct features of the initial stages of embryogenesis in gymnosperms and angiosperms, it is relevant to investigate to what extent such differences emerge from differential regulation mediated by sncRNAs. Within these, the microRNAs (miRNAs) are the best characterized class, and while many miRNAs are conserved and significantly represented across angiosperms and other seed plants during embryogenesis, some miRNA families are specific to some plant lineages. Being a model to study zygotic embryogenesis and a relevant biotechnological tool, we systematized the current knowledge on the presence and characterization of miRNAs in somatic embryogenesis (SE) of seed plants, pinpointing the miRNAs that have been reported to be associated with SE in angiosperm and gymnosperm species. We start by conducting an overview of sncRNA expression profiles in the embryonic tissues of seed plants. We then highlight the miRNAs described as being involved in the different stages of the SE process, from its induction to the full maturation of the somatic embryos, adding references to zygotic embryogenesis when relevant, as a contribution towards a better understanding of miRNA-mediated regulation of SE.
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Affiliation(s)
- Ana Alves
- BioISI—Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, 1749-016 Lisboa, Portugal;
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, 2780-157 Oeiras, Portugal
| | - Daniela Cordeiro
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal; (D.C.); (S.C.)
| | - Sandra Correia
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal; (D.C.); (S.C.)
| | - Célia Miguel
- BioISI—Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisboa, 1749-016 Lisboa, Portugal;
- iBET, Instituto de Biologia Experimental e Tecnológica, Apartado 12, 2781-901 Oeiras, Portugal
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Perdiguero P, Rodrigues AS, Chaves I, Costa B, Alves A, de María N, Vélez MD, Díaz-Sala C, Cervera MT, Miguel CM. Comprehensive analysis of the isomiRome in the vegetative organs of the conifer Pinus pinaster under contrasting water availability. PLANT, CELL & ENVIRONMENT 2021; 44:706-728. [PMID: 33314160 DOI: 10.1111/pce.13976] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 11/30/2020] [Indexed: 06/12/2023]
Abstract
An increasing number of microRNAs (miRNAs) and miRNA-related sequences produced during miRNA biogenesis, comprising the isomiRome, have been recently highlighted in different species as critical mediators of environmental stress responses. Conifers have some of the largest known genomes but an extensive characterization of the isomiRome from any conifer species has been lacking. We provide here a comprehensive overview of the Pinus pinaster isomiRome expressed in roots, stem and needles under well-watered and drought conditions. From the 13,441 unique small RNA sequences identified, 2,980 were annotated as canonical miRNAs or miRNA* and the remaining were classified as isomiRNA or miRNA-like sequences. A survey of their expression patterns highlighted roots as the most responsive organ under drought, where specific sequences of which a 24-nt novel miRNA stood out, were strongly down-regulated. Given the putative roles of the miRNA-targeted transcripts validated specifically in root tissues, some of the miRNAs, conserved and novel, are shortlisted as potential regulators of drought response. These results provide a valuable resource for comparative studies between gymnosperms and angiosperms. Furthermore, it evidences high transferability of the isomiRome between pine species being a useful basis for further molecular regulation and physiological studies, and especially those focused on adaptation to drought conditions.
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Affiliation(s)
- Pedro Perdiguero
- iBET, Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
- Centro de Investigación en Sanidad Animal (CISA-INIA), Madrid, Spain
| | - Andreia Santos Rodrigues
- iBET, Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Inês Chaves
- iBET, Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Bruno Costa
- iBET, Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
- BioISI-Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Ana Alves
- BioISI-Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Nuria de María
- Departamento de Ecología y Genética Forestal, INIA-CIFOR, Madrid, Spain
- Unidad Mixta de Genómica y Ecofisiología Forestal, INIA/UPM, Madrid, Spain
| | - María Dolores Vélez
- Departamento de Ecología y Genética Forestal, INIA-CIFOR, Madrid, Spain
- Unidad Mixta de Genómica y Ecofisiología Forestal, INIA/UPM, Madrid, Spain
| | - Carmen Díaz-Sala
- Departamento de Ciencias de la Vida, Universidad de Alcalá, Madrid, Spain
| | - María Teresa Cervera
- Departamento de Ecología y Genética Forestal, INIA-CIFOR, Madrid, Spain
- Unidad Mixta de Genómica y Ecofisiología Forestal, INIA/UPM, Madrid, Spain
| | - Célia Maria Miguel
- iBET, Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal
- BioISI-Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
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Cao H, Zhang X, Ruan Y, Zhang L, Cui Z, Li X, Jia B. miRNA expression profiling and zeatin dynamic changes in a new model system of in vivo indirect regeneration of tomato. PLoS One 2020; 15:e0237690. [PMID: 33332392 PMCID: PMC7745965 DOI: 10.1371/journal.pone.0237690] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/27/2020] [Indexed: 01/15/2023] Open
Abstract
Callus formation and adventitious shoot differentiation could be observed on the cut surface of completely decapitated tomato plants. We propose that this process can be used as a model system to investigate the mechanisms that regulate indirect regeneration of higher plants without the addition of exogenous hormones. This study analyzed the patterns of trans-zeatin and miRNA expression during in vivo regeneration of tomato. Analysis of trans-zeatin revealed that the hormone cytokinin played an important role in in vivo regeneration of tomato. Among 183 miRNAs and 1168 predicted target genes sequences identified, 93 miRNAs and 505 potential targets were selected based on differential expression levels for further characterization. Expression patterns of six miRNAs, including sly-miR166, sly-miR167, sly-miR396, sly-miR397, novel 156, and novel 128, were further validated by qRT-PCR. We speculate that sly-miR156, sly-miR160, sly-miR166, and sly-miR397 play major roles in callus formation of tomato during in vivo regeneration by regulating cytokinin, IAA, and laccase levels. Overall, our microRNA sequence and target analyses of callus formation during in vivo regeneration of tomato provide novel insights into the regulation of regeneration in higher plants.
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Affiliation(s)
- Huiying Cao
- College of Biological Science and Technology, Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang Key Laboratory of Maize Genomic Selection Breeding, Shenyang Agricultural University, Shenyang, China
| | - Xinyue Zhang
- College of Biological Science and Technology, Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang Key Laboratory of Maize Genomic Selection Breeding, Shenyang Agricultural University, Shenyang, China
| | - Yanye Ruan
- College of Biological Science and Technology, Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang Key Laboratory of Maize Genomic Selection Breeding, Shenyang Agricultural University, Shenyang, China
- * E-mail: (YR); (LZ)
| | - Lijun Zhang
- College of Biological Science and Technology, Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang Key Laboratory of Maize Genomic Selection Breeding, Shenyang Agricultural University, Shenyang, China
- * E-mail: (YR); (LZ)
| | - Zhenhai Cui
- College of Biological Science and Technology, Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang Key Laboratory of Maize Genomic Selection Breeding, Shenyang Agricultural University, Shenyang, China
| | - Xuxiao Li
- College of Biological Science and Technology, Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang Key Laboratory of Maize Genomic Selection Breeding, Shenyang Agricultural University, Shenyang, China
| | - Bing Jia
- College of Biological Science and Technology, Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang Key Laboratory of Maize Genomic Selection Breeding, Shenyang Agricultural University, Shenyang, China
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Wójcik AM. Research Tools for the Functional Genomics of Plant miRNAs During Zygotic and Somatic Embryogenesis. Int J Mol Sci 2020; 21:E4969. [PMID: 32674459 PMCID: PMC7420248 DOI: 10.3390/ijms21144969] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 12/12/2022] Open
Abstract
During early plant embryogenesis, some of the most fundamental decisions on fate and identity are taken making it a fascinating process to study. It is no surprise that higher plant embryogenesis was intensively analysed during the last century, while somatic embryogenesis is probably the most studied regeneration model. Encoded by the MIRNA, short, single-stranded, non-coding miRNAs, are commonly present in all Eukaryotic genomes and are involved in the regulation of the gene expression during the essential developmental processes such as plant morphogenesis, hormone signaling, and developmental phase transition. During the last few years dedicated to miRNAs, analytical methods and tools have been developed, which have afforded new opportunities in functional analyses of plant miRNAs, including (i) databases for in silico analysis; (ii) miRNAs detection and expression approaches; (iii) reporter and sensor lines for a spatio-temporal analysis of the miRNA-target interactions; (iv) in situ hybridisation protocols; (v) artificial miRNAs; (vi) MIM and STTM lines to inhibit miRNA activity, and (vii) the target genes resistant to miRNA. Here, we attempted to summarise the toolbox for functional analysis of miRNAs during plant embryogenesis. In addition to characterising the described tools/methods, examples of the applications have been presented.
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Affiliation(s)
- Anna Maria Wójcik
- University of Silesia in Katowice, Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, Jagiellonska 28, 40-032 Katowice, Poland
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Wójcikowska B, Wójcik AM, Gaj MD. Epigenetic Regulation of Auxin-Induced Somatic Embryogenesis in Plants. Int J Mol Sci 2020; 21:ijms21072307. [PMID: 32225116 PMCID: PMC7177879 DOI: 10.3390/ijms21072307] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 03/17/2020] [Accepted: 03/24/2020] [Indexed: 12/22/2022] Open
Abstract
Somatic embryogenesis (SE) that is induced in plant explants in response to auxin treatment is closely associated with an extensive genetic reprogramming of the cell transcriptome. The significant modulation of the gene transcription profiles during SE induction results from the epigenetic factors that fine-tune the gene expression towards embryogenic development. Among these factors, microRNA molecules (miRNAs) contribute to the post-transcriptional regulation of gene expression. In the past few years, several miRNAs that regulate the SE-involved transcription factors (TFs) have been identified, and most of them were involved in the auxin-related processes, including auxin metabolism and signaling. In addition to miRNAs, chemical modifications of DNA and chromatin, in particular the methylation of DNA and histones and histone acetylation, have been shown to shape the SE transcriptomes. In response to auxin, these epigenetic modifications regulate the chromatin structure, and hence essentially contribute to the control of gene expression during SE induction. In this paper, we describe the current state of knowledge with regard to the SE epigenome. The complex interactions within and between the epigenetic factors, the key SE TFs that have been revealed, and the relationships between the SE epigenome and auxin-related processes such as auxin perception, metabolism, and signaling are highlighted.
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Wójcik AM, Wójcikowska B, Gaj MD. Current Perspectives on the Auxin-Mediated Genetic Network that Controls the Induction of Somatic Embryogenesis in Plants. Int J Mol Sci 2020; 21:E1333. [PMID: 32079138 PMCID: PMC7072907 DOI: 10.3390/ijms21041333] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 02/07/2020] [Accepted: 02/14/2020] [Indexed: 12/22/2022] Open
Abstract
Auxin contributes to almost every aspect of plant development and metabolism as well as the transport and signalling of auxin-shaped plant growth and morphogenesis in response to endo- and exogenous signals including stress conditions. Consistently with the common belief that auxin is a central trigger of developmental changes in plants, the auxin treatment of explants was reported to be an indispensable inducer of somatic embryogenesis (SE) in a large number of plant species. Treating in vitro-cultured tissue with auxins (primarily 2,4-dichlorophenoxyacetic acid, which is a synthetic auxin-like plant growth regulator) results in the extensive reprogramming of the somatic cell transcriptome, which involves the modulation of numerous SE-associated transcription factor genes (TFs). A number of SE-modulated TFs that control auxin metabolism and signalling have been identified, and conversely, the regulators of the auxin-signalling pathway seem to control the SE-involved TFs. In turn, the different expression of the genes encoding the core components of the auxin-signalling pathway, the AUXIN/INDOLE-3-ACETIC ACIDs (Aux/IAAs) and AUXIN RESPONSE FACTORs (ARFs), was demonstrated to accompany SE induction. Thus, the extensive crosstalk between the hormones, in particular, auxin and the TFs, was revealed to play a central role in the SE-regulatory network. Accordingly, LEAFY COTYLEDON (LEC1 and LEC2), BABY BOOM (BBM), AGAMOUS-LIKE15 (AGL15) and WUSCHEL (WUS) were found to constitute the central part of the complex regulatory network that directs the somatic plant cell towards embryogenic development in response to auxin. The revealing picture shows a high degree of complexity of the regulatory relationships between the TFs of the SE-regulatory network, which involve direct and indirect interactions and regulatory feedback loops. This review examines the recent advances in studies on the auxin-controlled genetic network, which is involved in the mechanism of SE induction and focuses on the complex regulatory relationships between the down- and up-stream targets of the SE-regulatory TFs. In particular, the outcomes from investigations on Arabidopsis, which became a model plant in research on genetic control of SE, are presented.
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Nakamura M, Köhler C, Hennig L. Tissue-specific transposon-associated small RNAs in the gymnosperm tree, Norway spruce. BMC Genomics 2019; 20:997. [PMID: 31856707 PMCID: PMC6923980 DOI: 10.1186/s12864-019-6385-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 12/11/2019] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Small RNAs (sRNAs) are regulatory molecules impacting on gene expression and transposon activity. MicroRNAs (miRNAs) are responsible for tissue-specific and environmentally-induced gene repression. Short interfering RNAs (siRNA) are constitutively involved in transposon silencing across different type of tissues. The male gametophyte in angiosperms has a unique set of sRNAs compared to vegetative tissues, including phased siRNAs from intergenic or genic regions, or epigenetically activated siRNAs. This is contrasted by a lack of knowledge about the sRNA profile of the male gametophyte of gymnosperms. RESULTS Here, we isolated mature pollen from male cones of Norway spruce and investigated its sRNA profiles. While 21-nt sRNAs is the major size class of sRNAs in needles, in pollen 21-nt and 24-nt sRNAs are the most abundant size classes. Although the 24-nt sRNAs were exclusively derived from TEs in pollen, both 21-nt and 24-nt sRNAs were associated with TEs. We also investigated sRNAs from somatic embryonic callus, which has been reported to contain 24-nt sRNAs. Our data show that the 24-nt sRNA profiles are tissue-specific and differ between pollen and cell culture. CONCLUSION Our data reveal that gymnosperm pollen, like angiosperm pollen, has a unique sRNA profile, differing from vegetative leaf tissue. Thus, our results reveal that angiosperm and gymnosperm pollen produce new size classes not present in vegetative tissues; while in angiosperm pollen 21-nt sRNAs are generated, in the gymnosperm Norway spruce 24-nt sRNAs are generated. The tissue-specific production of distinct TE-derived sRNAs in angiosperms and gymnosperms provides insights into the diversification process of sRNAs in TE silencing pathways between the two groups of seed plants.
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Affiliation(s)
- Miyuki Nakamura
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden.
| | - Claudia Köhler
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Lars Hennig
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
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