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Murik O, Geffen O, Shotland Y, Fernandez-Pozo N, Ullrich KK, Walther D, Rensing SA, Treves H. Genomic imprints of unparalleled growth. THE NEW PHYTOLOGIST 2024; 241:1144-1160. [PMID: 38072860 DOI: 10.1111/nph.19444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 10/31/2023] [Indexed: 12/23/2023]
Abstract
Chlorella ohadii was isolated from desert biological soil crusts, one of the harshest habitats on Earth, and is emerging as an exciting new green model for studying growth, photosynthesis and metabolism under a wide range of conditions. Here, we compared the genome of C. ohadii, the fastest growing alga on record, to that of other green algae, to reveal the genomic imprints empowering its unparalleled growth rate and resistance to various stressors, including extreme illumination. This included the genome of its close relative, but slower growing and photodamage sensitive, C. sorokiniana UTEX 1663. A larger number of ribosome-encoding genes, high intron abundance, increased codon bias and unique genes potentially involved in metabolic flexibility and resistance to photodamage are all consistent with the faster growth of C. ohadii. Some of these characteristics highlight general trends in Chlorophyta and Chlorella spp. evolution, and others open new broad avenues for mechanistic exploration of their relationship with growth. This work entails a unique case study for the genomic adaptations and costs of exceptionally fast growth and sheds light on the genomic signatures of fast growth in photosynthetic cells. It also provides an important resource for future studies leveraging the unique properties of C. ohadii for photosynthesis and stress response research alongside their utilization for synthetic biology and biotechnology aims.
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Affiliation(s)
- Omer Murik
- Department of Plant and Environmental Sciences, Hebrew University of Jerusalem, 91904, Jerusalem, Israel
- Medical Genetics Institute, Shaare Zedek Medical Center, 93722, Jerusalem, Israel
| | - Or Geffen
- School of Plant Sciences and Food Security, Tel-Aviv University, 39040, Tel-Aviv, Israel
| | - Yoram Shotland
- Chemical Engineering, Shamoon College of Engineering, 84100, Beer-Sheva, Israel
| | - Noe Fernandez-Pozo
- Plant Cell Biology, Department of Biology, University of Marburg, 35037, Marburg, Germany
| | - Kristian Karsten Ullrich
- Plant Cell Biology, Department of Biology, University of Marburg, 35037, Marburg, Germany
- Max-Planck Institute for Evolutionary Biology, 24306, Plön, Germany
| | - Dirk Walther
- Max-Planck Institute for Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Stefan Andreas Rensing
- Plant Cell Biology, Department of Biology, University of Marburg, 35037, Marburg, Germany
- Center for Biological Signaling Studies (BIOSS), University of Freiburg, 79098, Freiburg, Germany
| | - Haim Treves
- School of Plant Sciences and Food Security, Tel-Aviv University, 39040, Tel-Aviv, Israel
- Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, 67663, Kaiserslautern, Germany
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Lebedev V. Impact of Intron and Retransformation on Transgene Expression in Leaf and Fruit Tissues of Field-Grown Pear Trees. Int J Mol Sci 2023; 24:12883. [PMID: 37629068 PMCID: PMC10454629 DOI: 10.3390/ijms241612883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/26/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
Stable and high expression of introduced genes is a prerequisite for using transgenic trees. Transgene stacking enables combining several valuable traits, but repeated transformation increases the risk of unintended effects. This work studied the stability and intron-mediated enhancement of uidA gene expression in leaves and different anatomical parts of pear fruits during field trials over 14 years. The stability of reporter and herbicide resistance transgenes in retransformed pear plants, as well as possible unintended effects using high-throughput phenotyping tools, were also investigated. The activity of β-glucuronidase (GUS) varied depending on the year, but silencing did not occur. The uidA gene was expressed to a maximum in seeds, slightly less in the peel and peduncles, and much less in the pulp of pear fruits. The intron in the uidA gene stably increased expression in leaves and fruits by approximately twofold. Retransformants with the bar gene showed long-term herbicide resistance and exhibited no consistent changes in leaf size and shape. The transgenic pear was used as rootstock and scion, but grafted plants showed no transport of the GUS protein through the graft in the greenhouse and field. This longest field trial of transgenic fruit trees demonstrates stable expression under varying environmental conditions, the expression-enhancing effect of intron and the absence of unintended effects in single- and double-transformed woody plants.
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Affiliation(s)
- Vadim Lebedev
- Branch of the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, 142290 Pushchino, Russia
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3
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Gramma V, Wahl V. RNA In Situ Hybridization on Plant Tissue Sections: Expression Analysis at Cellular Resolution. Methods Mol Biol 2023; 2686:331-350. [PMID: 37540368 DOI: 10.1007/978-1-0716-3299-4_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
RNA in situ hybridization offers a means to study the spatial expression of candidate genes by making use of specific, labelled RNA probes on thin tissue sections. Unlike other methods, such as promoter GUS fusions, for which all regulatory sequences should be available and transgenic plants have to be generated, RNA in situ hybridization allows specific and direct detection of even low abundant transcripts at cellular resolution. Although various protocols exist, the results published throughout the literature indicate a very obvious problem of the technique: each step has the potential to affect the outcome, that is, the signal strength, presence or absence of background, and visibility of individual cells. The protocol described here tries to avoid all these problems by addressing each step in detail and providing advice regarding critical steps for a distinct visualization of gene expression on intact tissue sections without any background.
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Affiliation(s)
| | - Vanessa Wahl
- Max Planck Institute of Plant Physiology, Potsdam, Germany.
- The James Hutton Institute, Dundee, UK.
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Wang J, Xi X, Zhao S, Wang X, Yao L, Feng J, Han R. Introns in the Naa50 gene act as strong enhancers of tissue-specific expression in Arabidopsis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 324:111422. [PMID: 35988583 DOI: 10.1016/j.plantsci.2022.111422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 07/30/2022] [Accepted: 08/14/2022] [Indexed: 06/15/2023]
Abstract
Naa50 is the catalytic subunit of N-terminal acetyltransferase complex E, which plays an important role in regulating plant development, endoplasmic reticulum stress and immune responses in Arabidopsis. In this study, the complete genomic sequence (but not the coding sequence) of Naa50 rescued the phenotype of Naa50 deletion mutants. Naa50 expression was noted in whole roots except for central root cap cells. The deletion of intron 1 resulted in a loss of Naa50 expression in the root meristem zone and in the epidermis, cortex and endodermis of the elongation zone and mature zone, while the deletion of intron 2 decreased Naa50 expression in the epidermis, cortex and endodermis of the root elongation zone and mature zone. The native Naa50 promoter together with introns 1 and 2 promotes the expression of Naa50 in sepal vascular bundles, filaments, pollen and stigmas; however, neither intron has positive effect on Naa50 expression in mature rosette leaves. The results of this study show that introns 1 and 2 in the Naa50 gene function as enhancers to promote the tissue-specific expression of Naa50.
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Affiliation(s)
- Jin Wang
- Higher Education Key Laboratory of Plant Molecular and Environment Stress Response (Shanxi Normal University) in Shanxi Province, Taiyuan 030000, Shanxi, China
| | - Xiaoyu Xi
- Higher Education Key Laboratory of Plant Molecular and Environment Stress Response (Shanxi Normal University) in Shanxi Province, Taiyuan 030000, Shanxi, China; College of Life Sciences, Shanxi Normal University, Taiyuan 030000, Shanxi, China
| | - Shifeng Zhao
- Higher Education Key Laboratory of Plant Molecular and Environment Stress Response (Shanxi Normal University) in Shanxi Province, Taiyuan 030000, Shanxi, China; College of Life Sciences, Shanxi Normal University, Taiyuan 030000, Shanxi, China
| | - Xiaolei Wang
- Higher Education Key Laboratory of Plant Molecular and Environment Stress Response (Shanxi Normal University) in Shanxi Province, Taiyuan 030000, Shanxi, China; College of Life Sciences, Shanxi Normal University, Taiyuan 030000, Shanxi, China
| | - Lixia Yao
- Higher Education Key Laboratory of Plant Molecular and Environment Stress Response (Shanxi Normal University) in Shanxi Province, Taiyuan 030000, Shanxi, China; College of Life Sciences, Shanxi Normal University, Taiyuan 030000, Shanxi, China
| | - Jinlin Feng
- Higher Education Key Laboratory of Plant Molecular and Environment Stress Response (Shanxi Normal University) in Shanxi Province, Taiyuan 030000, Shanxi, China; College of Life Sciences, Shanxi Normal University, Taiyuan 030000, Shanxi, China.
| | - Rong Han
- Higher Education Key Laboratory of Plant Molecular and Environment Stress Response (Shanxi Normal University) in Shanxi Province, Taiyuan 030000, Shanxi, China; College of Life Sciences, Shanxi Normal University, Taiyuan 030000, Shanxi, China.
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Pan W, Liu X, Li D, Zhang H. Establishment of an Efficient Genome Editing System in Lettuce Without Sacrificing Specificity. FRONTIERS IN PLANT SCIENCE 2022; 13:930592. [PMID: 35812897 PMCID: PMC9257259 DOI: 10.3389/fpls.2022.930592] [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: 04/28/2022] [Accepted: 05/23/2022] [Indexed: 06/15/2023]
Abstract
The efficiency of the CRISPR/Cas9 genome editing system remains limited in many crops. Utilizing strong promoters to boost the expression level of Cas9 are commonly used to improve the editing efficiency. However, these strategies also increase the risk of off-target mutation. Here, we developed a new strategy to utilize intron-mediated enhancement (IME)-assisted 35S promoter to drive Cas9 and sgRNA in a single transcript, which escalates the editing efficiency by moderately enhancing the expression of both Cas9 and sgRNA. In addition, we developed another strategy to enrich cells highly expressing Cas9/sgRNA by co-expressing the developmental regulator gene GRF5, which has been proved to ameliorate the transformation efficiency, and the transgenic plants from these cells also exhibited enhanced editing efficiency. This system elevated the genome editing efficiency from 14-28% to 54-81% on three targets tested in lettuce (Lactuca sativa) without increasing the off-target editing efficiency. Thus, we established a new genome editing system with highly improved on-target editing efficiency and without obvious increasement in off-target effects, which can be used to characterize genes of interest in lettuce and other crops.
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Affiliation(s)
- Wenbo Pan
- Peking University Institute of Advanced Agricultural Science, Weifang, China
- School of Advanced Agricultural Sciences, Peking University, Beijing, China
| | - Xue Liu
- National Engineering Research Center for Vegetables, Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Science, Beijing, China
- Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, China
| | - Dayong Li
- National Engineering Research Center for Vegetables, Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Science, Beijing, China
- Beijing Key Laboratory of Vegetable Germplasm Improvement, Beijing, China
| | - Huawei Zhang
- Peking University Institute of Advanced Agricultural Science, Weifang, China
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Schmitz RJ, Grotewold E, Stam M. Cis-regulatory sequences in plants: Their importance, discovery, and future challenges. THE PLANT CELL 2022; 34:718-741. [PMID: 34918159 PMCID: PMC8824567 DOI: 10.1093/plcell/koab281] [Citation(s) in RCA: 110] [Impact Index Per Article: 55.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 10/20/2021] [Indexed: 05/19/2023]
Abstract
The identification and characterization of cis-regulatory DNA sequences and how they function to coordinate responses to developmental and environmental cues is of paramount importance to plant biology. Key to these regulatory processes are cis-regulatory modules (CRMs), which include enhancers and silencers. Despite the extraordinary advances in high-quality sequence assemblies and genome annotations, the identification and understanding of CRMs, and how they regulate gene expression, lag significantly behind. This is especially true for their distinguishing characteristics and activity states. Here, we review the current knowledge on CRMs and breakthrough technologies enabling identification, characterization, and validation of CRMs; we compare the genomic distributions of CRMs with respect to their target genes between different plant species, and discuss the role of transposable elements harboring CRMs in the evolution of gene expression. This is an exciting time to study cis-regulomes in plants; however, significant existing challenges need to be overcome to fully understand and appreciate the role of CRMs in plant biology and in crop improvement.
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Affiliation(s)
- Robert J Schmitz
- Department of Genetics, University of Georgia, Athens, Georgia 30602, USA
| | - Erich Grotewold
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
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