1
|
Zou LH, Zhu B, Chen Y, Lu Y, Ramkrishnan M, Xu C, Zhou X, Ding Y, Cho J, Zhou M. Genetic and epigenetic reprogramming in response to internal and external cues by induced transposon mobilization in Moso bamboo. THE NEW PHYTOLOGIST 2024. [PMID: 39238152 DOI: 10.1111/nph.20107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2024] [Accepted: 08/21/2024] [Indexed: 09/07/2024]
Abstract
Long terminal repeat retroelements (LTR-REs) have profound effects on DNA methylation and gene regulation. Despite the vast abundance of LTR-REs in the genome of Moso bamboo (Phyllostachys edulis), an industrial crop in underdeveloped countries, their precise implication of the LTR-RE mobility in stress response and development remains unknown. We investigated the RNA and DNA products of LTR-REs in Moso bamboo under various developmental stages and stressful conditions. Surprisingly, our analyses identified thousands of active LTR-REs, particularly those located near genes involved in stress response and developmental regulation. These genes adjacent to active LTR-REs exhibited an increased expression under stress and are associated with reduced DNA methylation that is likely affected by the induced LTR-REs. Moreover, the analyses of simultaneous mapping of insertions and DNA methylation showed that the LTR-REs effectively alter the epigenetic status of the genomic regions where they inserted, and concomitantly their transcriptional competence which might impact the stress resilience and growth of the host. Our work unveils the unusually strong LTR-RE mobility in Moso bamboo and its close association with (epi)genetic changes, which supports the co-evolution of the parasitic DNAs and host genome in attaining stress tolerance and developmental robustness.
Collapse
Affiliation(s)
- Long-Hai Zou
- State Key Laboratory of Subtropical Silviculture, Bamboo Industry Institute, Zhejiang A&F University, Hangzhou, Zhejiang, 311300, China
| | - Bailiang Zhu
- State Key Laboratory of Subtropical Silviculture, Bamboo Industry Institute, Zhejiang A&F University, Hangzhou, Zhejiang, 311300, China
| | - Yaxin Chen
- State Key Laboratory of Subtropical Silviculture, Bamboo Industry Institute, Zhejiang A&F University, Hangzhou, Zhejiang, 311300, China
| | - Yaping Lu
- State Key Laboratory of Subtropical Silviculture, Bamboo Industry Institute, Zhejiang A&F University, Hangzhou, Zhejiang, 311300, China
| | - Muthusamy Ramkrishnan
- State Key Laboratory of Tree Genetics and Breeding, Co-Innovation Center for Sustainable Forestry in Southern China, Bamboo Research Institute, Key Laboratory of National Forestry and Grassland Administration on Subtropical Forest Biodiversity Conservation, College of Biology and the Environment, Nanjing Forestry University, Nanjing, Jiangsu, 210037, China
| | - Chao Xu
- State Key Laboratory of Subtropical Silviculture, Bamboo Industry Institute, Zhejiang A&F University, Hangzhou, Zhejiang, 311300, China
| | - Xiaohong Zhou
- State Key Laboratory of Subtropical Silviculture, Bamboo Industry Institute, Zhejiang A&F University, Hangzhou, Zhejiang, 311300, China
| | - Yiqian Ding
- State Key Laboratory of Subtropical Silviculture, Bamboo Industry Institute, Zhejiang A&F University, Hangzhou, Zhejiang, 311300, China
| | - Jungnam Cho
- Department of Biosciences, Durham University, Durham, DH1 3LE, UK
| | - Mingbing Zhou
- State Key Laboratory of Subtropical Silviculture, Bamboo Industry Institute, Zhejiang A&F University, Hangzhou, Zhejiang, 311300, China
| |
Collapse
|
2
|
Lee S, Park YS, Rhee JH, Chu H, Frost JM, Choi Y. Insights into plant regeneration: cellular pathways and DNA methylation dynamics. PLANT CELL REPORTS 2024; 43:120. [PMID: 38634973 PMCID: PMC11026228 DOI: 10.1007/s00299-024-03216-9] [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: 02/26/2024] [Accepted: 04/08/2024] [Indexed: 04/19/2024]
Abstract
Plants, known for their immobility, employ various mechanisms against stress and damage. A prominent feature is the formation of callus tissue-a cellular growth phenomenon that remains insufficiently explored, despite its distinctive cellular plasticity compared to vertebrates. Callus formation involves dedifferentiated cells, with a subset attaining pluripotency. Calluses exhibit an extraordinary capacity to reinitiate cellular division and undergo structural transformations, generating de novo shoots and roots, thereby developing into regenerated plants-a testament to the heightened developmental plasticity inherent in plants. In this way, plant regeneration through clonal propagation is a widely employed technique for vegetative reproduction. Thus, exploration of the biological components involved in regaining pluripotency contributes to the foundation upon which methods of somatic plant propagation can be advanced. This review provides an overview of the cellular pathway involved in callus and subsequent de novo shoot formation from already differentiated plant tissue, highlighting key genes critical to this process. In addition, it explores the intricate realm of epigenetic regulatory processes, emphasizing the nuanced dynamics of DNA methylation that contribute to plant regeneration. Finally, we briefly discuss somaclonal variation, examining its relation to DNA methylation, and investigating the heritability of epigenomic changes in crops.
Collapse
Affiliation(s)
- Seunga Lee
- Department of Biological Sciences, Seoul National University, Seoul, Korea
- Research Center for Plant Plasticity, Seoul National University, Seoul, Korea
| | - Young Seo Park
- Department of Biological Sciences, Seoul National University, Seoul, Korea
| | - Ji Hoon Rhee
- Department of Biological Sciences, Seoul National University, Seoul, Korea
- Research Center for Plant Plasticity, Seoul National University, Seoul, Korea
| | - Hyojeong Chu
- Department of Biological Sciences, Seoul National University, Seoul, Korea
- Research Center for Plant Plasticity, Seoul National University, Seoul, Korea
- The Research Institute of Basic Sciences, Seoul National University, Seoul, Korea
| | - Jennifer M Frost
- Genomics and Child Health, The Blizard Institute, Queen Mary University of London, London, UK
| | - Yeonhee Choi
- Department of Biological Sciences, Seoul National University, Seoul, Korea.
- Research Center for Plant Plasticity, Seoul National University, Seoul, Korea.
| |
Collapse
|
3
|
Xu X, Chen M, Chen T, Ni X, Fang Z, Fang Y, Zhang L, Zhang X, Huang J. Ultra-high static magnetic field induces a change in the spectrum but not frequency of DNA spontaneous mutations in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2023; 14:1305069. [PMID: 38126008 PMCID: PMC10731980 DOI: 10.3389/fpls.2023.1305069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 11/20/2023] [Indexed: 12/23/2023]
Abstract
Biological effects of magnetic fields have been extensively studied in plants, microorganisms and animals, and applications of magnetic fields in regulation of plant growth and phytoprotection is a promising field in sustainable agriculture. However, the effect of magnetic fields especially ultra-high static magnetic field (UHSMF) on genomic stability is largely unclear. Here, we investigated the mutagenicity of 24.5, 30.5 and 33.0 T UHSMFs with the gradient of 150, 95 and 0 T/m, respectively, via whole genome sequencing. Our results showed that 1 h exposure of Arabidopsis dried seeds to UHSMFs has no significant effect on the average rate of DNA mutations including single nucleotide variations and InDels (insertions and deletions) in comparison with the control, but 33.0 T and 24.5 T treatments lead to a significant change in the rate of nucleotide transitions and InDels longer than 3 bp, respectively, suggesting that both strength and gradient of UHSMF impact molecular spectrum of DNA mutations. We also found that the decreased transition rate in UHSMF groups is correlated with the upstream flanking sequences of G and C mutation sites. Furthermore, the germination rate of seeds exposed to 24.5 T SMF with -150 T/m gradient showed a significant decrease at 24 hours after sowing. Overall, our data lay a basis for precisely assessing the potential risk of UHSMF on DNA stability, and for elucidating molecular mechanism underlying gradient SMF-regulated biological processes in the future.
Collapse
Affiliation(s)
- Xiang Xu
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Mengjiao Chen
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Tianli Chen
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Xinda Ni
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Zhicai Fang
- Heye Health Industrial Research Institute of Heye Health Technology Co., Ltd., Huzhou, China
| | - Yanwen Fang
- Heye Health Industrial Research Institute of Heye Health Technology Co., Ltd., Huzhou, China
| | - Lei Zhang
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Xin Zhang
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Jirong Huang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| |
Collapse
|
4
|
Wibowo AT, Antunez-Sanchez J, Dawson A, Price J, Meehan C, Wrightsman T, Collenberg M, Bezrukov I, Becker C, Benhamed M, Weigel D, Gutierrez-Marcos J. Predictable and stable epimutations induced during clonal plant propagation with embryonic transcription factor. PLoS Genet 2022; 18:e1010479. [PMID: 36383565 PMCID: PMC9731469 DOI: 10.1371/journal.pgen.1010479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 12/08/2022] [Accepted: 10/15/2022] [Indexed: 11/17/2022] Open
Abstract
Clonal propagation is frequently used in commercial plant breeding and biotechnology programs because it minimizes genetic variation, yet it is not uncommon to observe clonal plants with stable phenotypic changes, a phenomenon known as somaclonal variation. Several studies have linked epigenetic modifications induced during regeneration with this newly acquired phenotypic variation. However, the factors that determine the extent of somaclonal variation and the molecular changes underpinning this process remain poorly understood. To address this gap in our knowledge, we compared clonally propagated Arabidopsis thaliana plants derived from somatic embryogenesis using two different embryonic transcription factors- RWP-RK DOMAIN-CONTAINING 4 (RKD4) or LEAFY COTYLEDON2 (LEC2) and from two epigenetically distinct founder tissues. We found that both the epi(genetic) status of the explant and the regeneration protocol employed play critical roles in shaping the molecular and phenotypic landscape of clonal plants. Phenotypic variation in regenerated plants can be largely explained by the inheritance of tissue-specific DNA methylation imprints, which are associated with specific transcriptional and metabolic changes in sexual progeny of clonal plants. For instance, regenerants were particularly affected by the inheritance of root-specific epigenetic imprints, which were associated with an increased accumulation of salicylic acid in leaves and accelerated plant senescence. Collectively, our data reveal specific pathways underpinning the phenotypic and molecular variation that arise and accumulate in clonal plant populations.
Collapse
Affiliation(s)
- Anjar Tri Wibowo
- School of Life Science, University of Warwick, Coventry, United Kingdom
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tubingen, Germany
- Department of Biology, Faculty of Science and Technology, Airlangga University, Surabaya City, East Java, Indonesia
| | | | - Alexander Dawson
- School of Life Science, University of Warwick, Coventry, United Kingdom
| | - Jonathan Price
- School of Life Science, University of Warwick, Coventry, United Kingdom
| | - Cathal Meehan
- School of Life Science, University of Warwick, Coventry, United Kingdom
| | - Travis Wrightsman
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tubingen, Germany
| | - Maximillian Collenberg
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tubingen, Germany
| | - Ilja Bezrukov
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tubingen, Germany
| | - Claude Becker
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tubingen, Germany
- Ludwig-Maximilians-University of Munich, Faculty of Biology, Biocenter, Martinsried, Germany
| | - Moussa Benhamed
- Université Paris-Saclay, Centre National de la Recherche Scientifique, Institut National De La Recherche Agronomique, University of Évry, Institute of Plant Sciences Paris-Saclay (IPS2), Orsay, France
| | - Detlef Weigel
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tubingen, Germany
- * E-mail: (DW); (JGM)
| | - Jose Gutierrez-Marcos
- School of Life Science, University of Warwick, Coventry, United Kingdom
- * E-mail: (DW); (JGM)
| |
Collapse
|
5
|
Genomic Variation Underlying the Breeding Selection of Quinoa Varieties Longli-4 and CA3-1 in China. Int J Mol Sci 2022; 23:ijms232214030. [PMID: 36430511 PMCID: PMC9693436 DOI: 10.3390/ijms232214030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/05/2022] [Accepted: 11/06/2022] [Indexed: 11/16/2022] Open
Abstract
Quinoa (Chenopodium quinoa) is a well-known climate-resilient crop and has been introduced into multiple marginal lands across the world, including China, to improve food security and/or balanced nutrient supplies. Conventional breeding has been widely applied in the selection and breeding of quinoa varieties in China since 1980s; however, few studies have been implemented on the genetic variances among different varieties developed by diversity breeding objectives. In this study, the phenotypic and genetic differences between two varieties (Longli-4 and CA3-1) from China were systematically analyzed. A total of 407,651 and 2,731,411 single nucleotide polymorphisms (SNPs) and 212,724 and 587,935 small insertion and deletion (INDELs) were detected for Longli-4 and CA3-1, respectively, when compared with the reference genome of PI614886. The SNPs/INDELs were unevenly distributed across each chromosome for both varieties. There were 143,996 SNPs and 83,410 INDELs shared between Longli-4 and CA3-1, accounting for 4% of the total variances. The variation was then screened based on the SNP effects. There were 818 and 73 genes with the variety-specific non-synonymous and stop-gain variation in Longli-4, whereas there were 13,701 and 733 genes in CA3-1. Specifically, 3501 genes with the non-synonymous variation and 74 genes with the stop-gain variation were found in both Longli-4 and CA3-1. These results suggest that convergent selection occurred during the different breeding processes. A set of candidate genes related to agronomic traits and domestication were further selected to detect the genetic divergence in detail in the two varieties. Only one domestication gene was identified having Longli-4-specific stop-gain variation. Twelve candidate genes related to betalain (1), flowering (4), seed size (2), domestication (1), and saponin (4) were identified having CA3-1-specific stop-gain variation. Interestingly, one seed size gene homologous of CKX1 (cytokinin oxidase/dehydrogenase 1) had the stop-gain variation in both varieties. This research will therefore provide guidance for the molecular-assisted breeding in quinoa.
Collapse
|
6
|
Hou BH, Tsai YH, Chiang MH, Tsao SM, Huang SH, Chao CP, Chen HM. Cultivar-specific markers, mutations, and chimerisim of Cavendish banana somaclonal variants resistant to Fusarium oxysporum f. sp. cubense tropical race 4. BMC Genomics 2022; 23:470. [PMID: 35752751 PMCID: PMC9233791 DOI: 10.1186/s12864-022-08692-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Abstract
Background The selection of tissue culture–derived somaclonal variants of Giant Cavendish banana (Musa spp., Cavendish sub-group AAA) by the Taiwan Banana Research Institute (TBRI) has resulted in several cultivars resistant to Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4), a destructive fungus threatening global banana production. However, the mutations in these somaclonal variants have not yet been determined. We performed an RNA-sequencing (RNA-seq) analysis of three TBRI Foc TR4–resistant cultivars: ‘Tai-Chiao No. 5’ (TC5), ‘Tai-Chiao No. 7’ (TC7), and ‘Formosana’ (FM), as well as their susceptible progenitor ‘Pei-Chiao’ (PC), to investigate the sequence variations among them and develop cultivar-specific markers. Results A group of single-nucleotide variants (SNVs) specific to one cultivar were identified from the analysis of RNA-seq data and validated using Sanger sequencing from genomic DNA. Several SNVs were further converted into cleaved amplified polymorphic sequence (CAPS) markers or derived CAPS markers that could identify the three Foc TR4–resistant cultivars among 6 local and 5 international Cavendish cultivars. Compared with PC, the three resistant cultivars showed a loss or alteration of heterozygosity in some chromosomal regions, which appears to be a consequence of single-copy chromosomal deletions. Notably, TC7 and FM shared a common deletion region on chromosome 5; however, different TC7 tissues displayed varying degrees of allele ratios in this region, suggesting the presence of chimerism in TC7. Conclusions This work demonstrates that reliable SNV markers of tissue culture–derived and propagated banana cultivars with a triploid genome can be developed through RNA-seq data analysis. Moreover, the analysis of sequence heterozygosity can uncover chromosomal deletions and chimerism in banana somaclonal variants. The markers obtained from this study will assist with the identification of TBRI Cavendish somaclonal variants for the quality control of tissue culture propagation, and the protection of breeders’ rights. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08692-5.
Collapse
Affiliation(s)
- Bo-Han Hou
- Agricultural Biotechnology Research Center, Academia Sinica, 11529, Taipei, Taiwan
| | - Yi-Heng Tsai
- Agricultural Biotechnology Research Center, Academia Sinica, 11529, Taipei, Taiwan
| | - Ming-Hau Chiang
- Agricultural Biotechnology Research Center, Academia Sinica, 11529, Taipei, Taiwan
| | - Shu-Ming Tsao
- Agricultural Biotechnology Research Center, Academia Sinica, 11529, Taipei, Taiwan
| | | | - Chih-Ping Chao
- Taiwan Banana Research Institute, 90442, Pingtung, Taiwan
| | - Ho-Ming Chen
- Agricultural Biotechnology Research Center, Academia Sinica, 11529, Taipei, Taiwan.
| |
Collapse
|
7
|
Pawełkowicz ME, Skarzyńska A, Koter MD, Turek S, Pląder W. miRNA Profiling and Its Role in Multi-Omics Regulatory Networks Connected with Somaclonal Variation in Cucumber ( Cucumis sativus L.). Int J Mol Sci 2022; 23:ijms23084317. [PMID: 35457133 PMCID: PMC9031375 DOI: 10.3390/ijms23084317] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/10/2022] [Accepted: 04/11/2022] [Indexed: 01/27/2023] Open
Abstract
The role of miRNAs in connection with the phenomenon of somaclonal variation, which occurs during plant in vitro culture, remains uncertain. This study aims to investigate the possible role of miRNAs in multi-omics regulatory pathways in cucumber somaclonal lines. For this purpose, we performed sRNA sequencing (sRNA-seq) from cucumber fruit samples identified 8, 10 and 44 miRNAs that are differentially expressed between somaclones (S1, S2, S3 lines) and the reference B10 line of Cucumis sativus. For miRNA identification, we use ShortStack software designed to filter miRNAs from sRNAs according to specific program criteria. The identification of predicted in-silico targets revealed 2,886 mRNAs encoded by 644 genes. The functional annotation of miRNA's target genes and gene ontology classification revealed their association with metabolic processes, response to stress, multicellular organism development, biosynthetic process and catalytic activity. We checked with bioinformatic analyses for possible interactions at the level of target proteins, differentially expressed genes (DEGs) and genes affected by genomic polymorphisms. We assume that miRNAs can indirectly influence molecular networks and play a role in many different regulatory pathways, leading to somaclonal variation. This regulation is supposed to occur through the process of the target gene cleavage or translation inhibition, which in turn affects the proteome, as we have shown in the example of molecular networks. This is a new approach combining levels from DNA-seq through mRNA-seq, sRNA-seq and in silico PPI in the area of plants' somaclonal variation.
Collapse
|
8
|
Ren Y, He Z, Liu P, Traw B, Sun S, Tian D, Yang S, Jia Y, Wang L. Somatic Mutation Analysis in Salix suchowensis Reveals Early-Segregated Cell Lineages. Mol Biol Evol 2021; 38:5292-5308. [PMID: 34562099 PMCID: PMC8662653 DOI: 10.1093/molbev/msab286] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Long-lived plants face the challenge of ever-increasing mutational burden across their long lifespan. Early sequestration of meristematic stem cells is supposed to efficiently slow down this process, but direct measurement of somatic mutations that accompanies segregated cell lineages in plants is still rare. Here, we tracked somatic mutations in 33 leaves and 22 adventitious roots from 22 stem-cuttings across eight major branches of a shrub willow (Salix suchowensis). We found that most mutations propagated separately in leaves and roots, providing clear evidence for early segregation of underlying cell lineages. By combining lineage tracking with allele frequency analysis, our results revealed a set of mutations shared by distinct branches, but were exclusively present in leaves and not in roots. These mutations were likely propagated by rapidly dividing somatic cell lineages which survive several iterations of branching, distinct from the slowly dividing axillary stem cell lineages. Leaf is thus contributed by both slowly and rapidly dividing cell lineages, leading to varied fixation chances of propagated mutations. By contrast, each root likely arises from a single founder cell within the adventitious stem cell lineages. Our findings give straightforward evidence that early segregation of meristems slows down mutation accumulation in axillary meristems, implying a plant "germline" paralog to the germline of animals through convergent evolution.
Collapse
Affiliation(s)
- Yifan Ren
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Zhen He
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Pingyu Liu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Brian Traw
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Shucun Sun
- Department of Ecology, School of Life Science, Nanjing University, Nanjing, China
| | - Dacheng Tian
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Sihai Yang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| | - Yanxiao Jia
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China
| | - Long Wang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, China
| |
Collapse
|
9
|
The Underlying Nature of Epigenetic Variation: Origin, Establishment, and Regulatory Function of Plant Epialleles. Int J Mol Sci 2021; 22:ijms22168618. [PMID: 34445323 PMCID: PMC8395315 DOI: 10.3390/ijms22168618] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/03/2021] [Accepted: 08/08/2021] [Indexed: 11/17/2022] Open
Abstract
In plants, the gene expression and associated phenotypes can be modulated by dynamic changes in DNA methylation, occasionally being fixed in certain genomic loci and inherited stably as epialleles. Epiallelic variations in a population can occur as methylation changes at an individual cytosine position, methylation changes within a stretch of genomic regions, and chromatin changes in certain loci. Here, we focus on methylated regions, since it is unclear whether variations at individual methylated cytosines can serve any regulatory function, and the evidence for heritable chromatin changes independent of genetic changes is limited. While DNA methylation is known to affect and regulate wide arrays of plant phenotypes, most epialleles in the form of methylated regions have not been assigned any biological function. Here, we review how epialleles can be established in plants, serve a regulatory function, and are involved in adaptive processes. Recent studies suggest that most epialleles occur as byproducts of genetic variations, mainly from structural variants and Transposable Element (TE) activation. Nevertheless, epialleles that occur spontaneously independent of any genetic variations have also been described across different plant species. Here, we discuss how epialleles that are dependent and independent of genetic architecture are stabilized in the plant genome and how methylation can regulate a transcription relative to its genomic location.
Collapse
|
10
|
Bednarek PT, Pachota KA, Dynkowska WM, Machczyńska J, Orłowska R. Understanding In Vitro Tissue Culture-Induced Variation Phenomenon in Microspore System. Int J Mol Sci 2021; 22:7546. [PMID: 34299165 PMCID: PMC8304781 DOI: 10.3390/ijms22147546] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/24/2021] [Accepted: 07/08/2021] [Indexed: 12/13/2022] Open
Abstract
In vitro tissue culture plant regeneration is a complicated process that requires stressful conditions affecting the cell functioning at multiple levels, including signaling pathways, transcriptome functioning, the interaction between cellular organelles (retro-, anterograde), compounds methylation, biochemical cycles, and DNA mutations. Unfortunately, the network linking all these aspects is not well understood, and the available knowledge is not systemized. Moreover, some aspects of the phenomenon are poorly studied. The present review attempts to present a broad range of aspects involved in the tissue culture-induced variation and hopefully would stimulate further investigations allowing a better understanding of the phenomenon and the cell functioning.
Collapse
Affiliation(s)
- Piotr Tomasz Bednarek
- Plant Breeding and Acclimatization Institute—National Research Institute, Radzików, 05-870 Błonie, Poland; (K.A.P.); (W.M.D.); (J.M.); (R.O.)
| | | | | | | | | |
Collapse
|
11
|
Orłowska R, Pachota KA, Dynkowska WM, Niedziela A, Bednarek PT. Androgenic-Induced Transposable Elements Dependent Sequence Variation in Barley. Int J Mol Sci 2021; 22:ijms22136783. [PMID: 34202586 PMCID: PMC8268840 DOI: 10.3390/ijms22136783] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/14/2021] [Accepted: 06/22/2021] [Indexed: 01/10/2023] Open
Abstract
A plant genome usually encompasses different families of transposable elements (TEs) that may constitute up to 85% of nuclear DNA. Under stressful conditions, some of them may activate, leading to sequence variation. In vitro plant regeneration may induce either phenotypic or genetic and epigenetic changes. While DNA methylation alternations might be related, i.e., to the Yang cycle problems, DNA pattern changes, especially DNA demethylation, may activate TEs that could result in point mutations in DNA sequence changes. Thus, TEs have the highest input into sequence variation (SV). A set of barley regenerants were derived via in vitro anther culture. High Performance Liquid Chromatography (RP-HPLC), used to study the global DNA methylation of donor plants and their regenerants, showed that the level of DNA methylation increased in regenerants by 1.45% compared to the donors. The Methyl-Sensitive Transposon Display (MSTD) based on methylation-sensitive Amplified Fragment Length Polymorphism (metAFLP) approach demonstrated that, depending on the selected elements belonging to the TEs family analyzed, varying levels of sequence variation were evaluated. DNA sequence contexts may have a different impact on SV generated by distinct mobile elements belonged to various TE families. Based on the presented study, some of the selected mobile elements contribute differently to TE-related SV. The surrounding context of the TEs DNA sequence is possibly important here, and the study explained some part of SV related to those contexts.
Collapse
|
12
|
Skarzyńska A, Pawełkowicz M, Pląder W. Influence of transgenesis on genome variability in cucumber lines with a thaumatin II gene. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2021; 27:985-996. [PMID: 34092948 PMCID: PMC8139995 DOI: 10.1007/s12298-021-00990-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 03/25/2021] [Accepted: 04/04/2021] [Indexed: 06/01/2023]
Abstract
UNLABELLED The development of new plant varieties by genetic modification aims at improving their features or introducing new qualities. However, concerns about the unintended effects of transgenes and negative environmental impact of genetically modified plants are an obstacle for the use of these plants in crops. To analyze the impact of transgenesis on plant genomes, we analyze three cucumber transgenic lines with an introduced thaumatin II gene. After genomes sequencing, we analyzed the transgene insertion site and performed variant prediction. As a result, we obtained similar number of variants for all analyzed lines (average of 4307 polymorphisms), with high abundance in one region of chromosome 4. According to SnpEff analysis, the presence of genomic variants generally does not influence the genome functionality, as less than 2% of polymorphisms have high impact. Moreover, analysis indicates that these changes were more likely induced by in vitro culture than by the transgenesis itself. The insertion site analysis shows that the region of transgene integration could cause changes in gene expression, by gene disruption or loss of promoter region continuity. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s12298-021-00990-8.
Collapse
Affiliation(s)
- Agnieszka Skarzyńska
- Department of Plant Genetics, Breeding and Biotechnology, Institute of Biology, Warsaw University of Life Sciences, Warsaw, Poland
| | - Magdalena Pawełkowicz
- Department of Plant Genetics, Breeding and Biotechnology, Institute of Biology, Warsaw University of Life Sciences, Warsaw, Poland
| | - Wojciech Pląder
- Department of Plant Genetics, Breeding and Biotechnology, Institute of Biology, Warsaw University of Life Sciences, Warsaw, Poland
| |
Collapse
|
13
|
Kim SJ, Park JS, Shin YH, Park YD. Identification and Validation of Genetic Variations in Transgenic Chinese Cabbage Plants ( Brassica rapa ssp. pekinensis) by Next-Generation Sequencing. Genes (Basel) 2021; 12:genes12050621. [PMID: 33922022 PMCID: PMC8143544 DOI: 10.3390/genes12050621] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 01/24/2023] Open
Abstract
Transgenic plants are usually produced through tissue culture, which is an essential step in Agrobacterium-mediated plant transformation. However, genomic variations, termed somaclonal variations, have been detected in transgenic plants cultured in vitro. The occurrence of these variations should be as low as possible to secure the stability of transgenic crops. Determining the cause and mechanism of somaclonal variations in tissue culture-derived plants will help reduce the rate of variation and promote the stable expression of genes in transgenic plants. In order to determine the genetic variability in transgenic Chinese cabbage plants, we performed whole-genome resequencing and compared the sequencing data with the ‘CT001’ reference genome. The variation candidates that were expected to consistently occur in the transgenic lines were selected and validated. The single nucleotide polymorphism (SNP) and insertion and deletion (InDel) candidates were identified using the resequencing data and validated by reverse transcription (RT)-PCR analysis. The deduced amino acid sequences were used to determine whether the variations caused changes in the resulting polypeptide, and the annotations of the mutated genes were analyzed to predict the possible effects of the SNPs on gene function. In conclusion, we selected and validated the genetic variations identified in transgenic Chinese cabbage plants. Their genomes were expected to be affected by the process of Agrobacterium-mediated transformation. The findings of our study will provide a genetic basis for transgenic plant research.
Collapse
Affiliation(s)
| | | | | | - Young-Doo Park
- Correspondence: ; Tel.: +82-10-3338-9344; Fax: +82-31-202-8395
| |
Collapse
|
14
|
Rajewski A, Carter-House D, Stajich J, Litt A. Datura genome reveals duplications of psychoactive alkaloid biosynthetic genes and high mutation rate following tissue culture. BMC Genomics 2021; 22:201. [PMID: 33752605 PMCID: PMC7986286 DOI: 10.1186/s12864-021-07489-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 02/26/2021] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Datura stramonium (Jimsonweed) is a medicinally and pharmaceutically important plant in the nightshade family (Solanaceae) known for its production of various toxic, hallucinogenic, and therapeutic tropane alkaloids. Recently, we published a tissue-culture based transformation protocol for D. stramonium that enables more thorough functional genomics studies of this plant. However, the tissue culture process can lead to undesirable phenotypic and genomic consequences independent of the transgene used. Here, we have assembled and annotated a draft genome of D. stramonium with a focus on tropane alkaloid biosynthetic genes. We then use mRNA sequencing and genome resequencing of transformants to characterize changes following tissue culture. RESULTS Our draft assembly conforms to the expected 2 gigabasepair haploid genome size of this plant and achieved a BUSCO score of 94.7% complete, single-copy genes. The repetitive content of the genome is 61%, with Gypsy-type retrotransposons accounting for half of this. Our gene annotation estimates the number of protein-coding genes at 52,149 and shows evidence of duplications in two key alkaloid biosynthetic genes, tropinone reductase I and hyoscyamine 6 β-hydroxylase. Following tissue culture, we detected only 186 differentially expressed genes, but were unable to correlate these changes in expression with either polymorphisms from resequencing or positional effects of transposons. CONCLUSIONS We have assembled, annotated, and characterized the first draft genome for this important model plant species. Using this resource, we show duplications of genes leading to the synthesis of the medicinally important alkaloid, scopolamine. Our results also demonstrate that following tissue culture, mutation rates of transformed plants are quite high (1.16 × 10- 3 mutations per site), but do not have a drastic impact on gene expression.
Collapse
Affiliation(s)
- Alex Rajewski
- Department of Botany and Plant Science, University of California, Riverside, California 92521 USA
| | - Derreck Carter-House
- Department of Microbiology and Plant Pathology, University of California, Riverside, California 92521 USA
| | - Jason Stajich
- Department of Microbiology and Plant Pathology, University of California, Riverside, California 92521 USA
| | - Amy Litt
- Department of Botany and Plant Science, University of California, Riverside, California 92521 USA
| |
Collapse
|
15
|
Tissue culture-induced DNA methylation in crop plants: a review. Mol Biol Rep 2021; 48:823-841. [PMID: 33394224 DOI: 10.1007/s11033-020-06062-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 12/03/2020] [Indexed: 12/15/2022]
Abstract
Plant tissue culture techniques have been extensively employed in commercial micropropagation to provide year-round production. Tissue culture regenerants are not always genotypically and phenotypically similar. Due to the changes in the tissue culture microenvironment, plant cells are exposed to additional stress which induces genetic and epigenetic instabilities in the regenerants. These changes lead to tissue culture-induced variations (TCIV) which are also known as somaclonal variations to categorically specify the inducing environment. TCIV includes molecular and phenotypic changes persuaded in the in vitro culture due to continuous sub-culturing and tissue culture-derived stress. Epigenetic variations such as altered DNA methylation pattern are induced due to the above-mentioned factors. Reportedly, alteration in DNA methylation pattern is much more frequent in the plant genome during the tissue culture process. DNA methylation plays an important role in gene expression and regulation of plant development. Variants originated in tissue culture process due to heritable methylation changes, can contribute to intra-species phenotypic variation. Several molecular techniques are available to detect DNA methylation at different stages of in vitro culture. Here, we review the aspects of TCIV with respect to DNA methylation and its effect on crop improvement programs. It is anticipated that a precise and comprehensive knowledge of molecular basis of in vitro-derived DNA methylation will help to design strategies to overcome the bottlenecks of micropropagation system and maintain the clonal fidelity of the regenerants.
Collapse
|
16
|
Belfield EJ, Brown C, Ding ZJ, Chapman L, Luo M, Hinde E, van Es SW, Johnson S, Ning Y, Zheng SJ, Mithani A, Harberd NP. Thermal stress accelerates Arabidopsis thaliana mutation rate. Genome Res 2020; 31:40-50. [PMID: 33334733 PMCID: PMC7849391 DOI: 10.1101/gr.259853.119] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 10/28/2020] [Indexed: 01/07/2023]
Abstract
Mutations are the source of both genetic diversity and mutational load. However, the effects of increasing environmental temperature on plant mutation rates and relative impact on specific mutational classes (e.g., insertion/deletion [indel] vs. single nucleotide variant [SNV]) are unknown. This topic is important because of the poorly defined effects of anthropogenic global temperature rise on biological systems. Here, we show the impact of temperature increase on Arabidopsis thaliana mutation, studying whole genome profiles of mutation accumulation (MA) lineages grown for 11 successive generations at 29°C. Whereas growth of A. thaliana at standard temperature (ST; 23°C) is associated with a mutation rate of 7 × 10−9 base substitutions per site per generation, growth at stressful high temperature (HT; 29°C) is highly mutagenic, increasing the mutation rate to 12 × 10−9. SNV frequency is approximately two- to threefold higher at HT than at ST, and HT-growth causes an ∼19- to 23-fold increase in indel frequency, resulting in a disproportionate increase in indels (vs. SNVs). Most HT-induced indels are 1–2 bp in size and particularly affect homopolymeric or dinucleotide A or T stretch regions of the genome. HT-induced indels occur disproportionately in nucleosome-free regions, suggesting that much HT-induced mutational damage occurs during cell-cycle phases when genomic DNA is packaged into nucleosomes. We conclude that stressful experimental temperature increases accelerate plant mutation rates and particularly accelerate the rate of indel mutation. Increasing environmental temperatures are thus likely to have significant mutagenic consequences for plants growing in the wild and may, in particular, add detrimentally to mutational load.
Collapse
Affiliation(s)
- Eric J Belfield
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| | - Carly Brown
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| | - Zhong Jie Ding
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom.,State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058 China
| | - Lottie Chapman
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom.,Faculty of Sciences, University of Geneva, Geneva 1211, Switzerland
| | - Mengqian Luo
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom.,Centre for Cell and Developmental Biology, State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Eleanor Hinde
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| | - Sam W van Es
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom.,Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, SE-901 87 Umeå, Sweden
| | - Sophie Johnson
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| | - Youzheng Ning
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom.,Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - Shao Jian Zheng
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058 China
| | - Aziz Mithani
- Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences (LUMS), DHA, Lahore 54792, Pakistan
| | - Nicholas P Harberd
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| |
Collapse
|
17
|
Evidence for the Accumulation of Nonsynonymous Mutations and Favorable Pleiotropic Alleles During Wheat Breeding. G3-GENES GENOMES GENETICS 2020; 10:4001-4011. [PMID: 32900902 PMCID: PMC7642940 DOI: 10.1534/g3.120.401269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Plant breeding leads to the genetic improvement of target traits by selecting a small number of genotypes from among typically large numbers of candidate genotypes after careful evaluation. In this study, we first investigated how mutations at conserved nucleotide sites normally viewed as deleterious, such as nonsynonymous sites, accumulated in a wheat, Triticum aestivum, breeding lineage. By comparing a 150 year old ancestral and modern cultivar, we found recent nucleotide polymorphisms altered amino acids and occurred within conserved genes at frequencies expected in the absence of purifying selection. Mutations that are deleterious in other contexts likely had very small or no effects on target traits within the breeding lineage. Second, we investigated if breeders selected alleles with favorable effects on some traits and unfavorable effects on others and used different alleles to compensate for the latter. An analysis of a segregating population derived from the ancestral and modern parents provided one example of this phenomenon. The recent cultivar contains the Rht-B1b green revolution semi-dwarfing allele and compensatory alleles that reduce its negative effects. However, improvements in traits other than plant height were due to pleiotropic loci with favorable effects on traits and to favorable loci with no detectable pleiotropic effects. Wheat breeding appears to tolerate mutations at conserved nucleotide sites and to only select for alleles with both favorable and unfavorable effects on traits in exceptional situations.
Collapse
|
18
|
Graham N, Patil GB, Bubeck DM, Dobert RC, Glenn KC, Gutsche AT, Kumar S, Lindbo JA, Maas L, May GD, Vega-Sanchez ME, Stupar RM, Morrell PL. Plant Genome Editing and the Relevance of Off-Target Changes. PLANT PHYSIOLOGY 2020; 183:1453-1471. [PMID: 32457089 PMCID: PMC7401131 DOI: 10.1104/pp.19.01194] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 05/07/2020] [Indexed: 05/12/2023]
Abstract
Site-directed nucleases (SDNs) used for targeted genome editing are powerful new tools to introduce precise genetic changes into plants. Like traditional approaches, such as conventional crossing and induced mutagenesis, genome editing aims to improve crop yield and nutrition. Next-generation sequencing studies demonstrate that across their genomes, populations of crop species typically carry millions of single nucleotide polymorphisms and many copy number and structural variants. Spontaneous mutations occur at rates of ∼10-8 to 10-9 per site per generation, while variation induced by chemical treatment or ionizing radiation results in higher mutation rates. In the context of SDNs, an off-target change or edit is an unintended, nonspecific mutation occurring at a site with sequence similarity to the targeted edit region. SDN-mediated off-target changes can contribute to a small number of additional genetic variants compared to those that occur naturally in breeding populations or are introduced by induced-mutagenesis methods. Recent studies show that using computational algorithms to design genome editing reagents can mitigate off-target edits in plants. Finally, crops are subject to strong selection to eliminate off-type plants through well-established multigenerational breeding, selection, and commercial variety development practices. Within this context, off-target edits in crops present no new safety concerns compared to other breeding practices. The current generation of genome editing technologies is already proving useful to develop new plant varieties with consumer and farmer benefits. Genome editing will likely undergo improved editing specificity along with new developments in SDN delivery and increasing genomic characterization, further improving reagent design and application.
Collapse
Affiliation(s)
- Nathaniel Graham
- Department of Genetics, Cell Biology and Development, University of Minnesota, St. Paul, Minnesota 55108
- Pairwise, Durham, North Carolina 27709
| | - Gunvant B Patil
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108
| | | | | | | | | | | | | | - Luis Maas
- Enza Zaden Research USA, San Juan Bautista, California 95045
| | | | | | - Robert M Stupar
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108
| | - Peter L Morrell
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108
| |
Collapse
|
19
|
Fang J, Wood AM, Chen Y, Yue J, Ming R. Genomic variation between PRSV resistant transgenic SunUp and its progenitor cultivar Sunset. BMC Genomics 2020; 21:398. [PMID: 32532215 PMCID: PMC7291442 DOI: 10.1186/s12864-020-06804-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 06/05/2020] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND The safety of genetically transformed plants remains a subject of scrutiny. Genomic variants in PRSV resistant transgenic papaya will provide evidence to rationally address such concerns. RESULTS In this study, a total of more than 74 million Illumina reads for progenitor 'Sunset' were mapped onto transgenic papaya 'SunUp' reference genome. 310,364 single nucleotide polymorphisms (SNPs) and 34,071 small Inserts/deletions (InDels) were detected between 'Sunset' and 'SunUp'. Those variations have an uneven distribution across nine chromosomes in papaya. Only 0.27% of mutations were predicted to be high-impact mutations. ATP-related categories were highly enriched among these high-impact genes. The SNP mutation rate was about 8.4 × 10- 4 per site, comparable with the rate induced by spontaneous mutation over numerous generations. The transition-to-transversion ratio was 1.439 and the predominant mutations were C/G to T/A transitions. A total of 3430 nuclear plastid DNA (NUPT) and 2764 nuclear mitochondrial DNA (NUMT) junction sites have been found in 'SunUp', which is proportionally higher than the predicted total NUPT and NUMT junction sites in 'Sunset' (3346 and 2745, respectively). Among all nuclear organelle DNA (norgDNA) junction sites, 96% of junction sites were shared by 'SunUp' and 'Sunset'. The average identity between 'SunUp' specific norgDNA and corresponding organelle genomes was higher than that of norgDNA shared by 'SunUp' and 'Sunset'. Six 'SunUp' organelle-like borders of transgenic insertions were nearly identical to corresponding sequences in organelle genomes (98.18 ~ 100%). None of the paired-end spans of mapped 'Sunset' reads were elongated by any 'SunUp' transformation plasmid derived inserts. Significant amounts of DNA were transferred from organelles to the nuclear genome during bombardment, including the six flanking sequences of the three transgenic insertions. CONCLUSIONS Comparative whole-genome analyses between 'SunUp' and 'Sunset' provide a reliable estimate of genome-wide variations and evidence of organelle-to-nucleus transfer of DNA associated with biolistic transformation.
Collapse
Affiliation(s)
- Jingping Fang
- The Public Service Platform for Industrialization Development Technology of Marine Biological Medicine and Product of State Oceanic Administration, Key Laboratory of Developmental and Neural Biology, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, Fujian, China.,Center of Engineering Technology Research for Microalgae Germplasm Improvement of Fujian, Southern Institute of Oceanography, Fujian Normal University, Fuzhou, 350117, Fujian, China.,FAFU and UIUC-SIB Joint Center for Genomics and Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China.,Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Andrew Michael Wood
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Youqiang Chen
- The Public Service Platform for Industrialization Development Technology of Marine Biological Medicine and Product of State Oceanic Administration, Key Laboratory of Developmental and Neural Biology, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, Fujian, China.,Center of Engineering Technology Research for Microalgae Germplasm Improvement of Fujian, Southern Institute of Oceanography, Fujian Normal University, Fuzhou, 350117, Fujian, China
| | - Jingjing Yue
- FAFU and UIUC-SIB Joint Center for Genomics and Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China
| | - Ray Ming
- FAFU and UIUC-SIB Joint Center for Genomics and Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China. .,Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
| |
Collapse
|
20
|
Park D, Choi IY, Kim NS. Detection of mPing mobilization in transgenic rice plants. Genes Genomics 2019; 42:47-54. [PMID: 31721104 DOI: 10.1007/s13258-019-00877-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/18/2019] [Indexed: 11/29/2022]
Abstract
BACKGROUND Various kinds of transposable elements (TEs) constitute high proportions of eukaryotic genomes. Although most of these TEs are not actively mobile, genome stress can induce mobilization of dormant TEs. Transgenic plants undergo tissue culture and subsequent whole-plant regeneration, which can cause genomic stress and in turn induce mobilization of inactive TEs. OBJECTIVES To investigate the activation of transposable elements on the genome wide of the GM plant. METHODS Transposon activities were analyzed in three transgenic rice plants carrying the insect resistance gene Cry1Ac and an herbicide resistance gene by the transposon display technique. These three transgenic plants were derived from a leading Korean rice variety, Illmi. RESULTS We detected seven mobile activities in the mPing element, which is a MITE family transposon. The identity of the novel fragments in the gel display was confirmed by checking TAA target site duplication via sequence analysis. The genomic integration sites were all on different chromosomes, and the integrations were specific to either one or two T1 transgenic lines, except for one common integration on chromosome 4. One integration was in the 5'-UTR of the Glycerol-3-phosphate acyltransferase 8 gene, two integrations were in introns of expressed genes, and the other four integrations were in intergenic regions. CONCLUSION Thus, novel mobilization of dormant TEs occurs in transgenic plants, which must be considered in the generation of genetically modified crops (GM crops).
Collapse
Affiliation(s)
- Doori Park
- Department of Agriculture and Life Industry, Kangwon National University, 1 Kangwondaehak-gil, Chuncheon-si, Gangwon-do, 24341, Republic of Korea
| | - Ik-Young Choi
- Department of Molecular Bioscience, Kangwon National University, 1 Kangwondaehak-gil, Chuncheon-si, Gangwon-do, 24341, Republic of Korea.
| | - Nam-Soo Kim
- Department of Agriculture and Life Industry, Kangwon National University, 1 Kangwondaehak-gil, Chuncheon-si, Gangwon-do, 24341, Republic of Korea.
| |
Collapse
|
21
|
Park JS, Park JH, Park YD. Construction of pseudomolecule sequences of Brassica rapa ssp. pekinensis inbred line CT001 and analysis of spontaneous mutations derived via sexual propagation. PLoS One 2019; 14:e0222283. [PMID: 31498838 PMCID: PMC6733507 DOI: 10.1371/journal.pone.0222283] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 08/26/2019] [Indexed: 01/27/2023] Open
Abstract
Chinese cabbage (Brassica rapa ssp. pekinensis) is a major crop that is widely cultivated, especially in Korea, Japan, and China. With the advent of next generation sequencing technology, the cost and time required for sequencing have decreased and the development of genome research accelerated. Genome sequencing of Chinese cabbage was completed in 2011 using the variety Chiifu-401-42, and since then the genome has been continuously updated. In the present study, we conducted whole-genome sequencing of Chinese cabbage inbred line CT001, a line widely used in traditional or molecular breeding, to improve the accuracy of genetic polymorphism analysis. The constructed CT001 pseudomolecule represented 85.4% (219.8 Mb) of the Chiifu reference genome, and a total of 38,567 gene models were annotated using RNA-Seq analysis. In addition, the spontaneous mutation rate of CT001 was estimated by resequencing DNA obtained from individual plants after sexual propagation for six generations to estimate the naturally occurring variations. The CT001 pseudomolecule constructed in this study will provide valuable resources for genomic studies on Chinese cabbage.
Collapse
Affiliation(s)
- Jee-Soo Park
- Department of Horticultural Biotechnology, Kyung Hee University, Yongin, Korea
| | - Ji-Hyun Park
- Department of Horticultural Biotechnology, Kyung Hee University, Yongin, Korea
| | - Young-Doo Park
- Department of Horticultural Biotechnology, Kyung Hee University, Yongin, Korea
- * E-mail:
| |
Collapse
|
22
|
Permyakova NV, Sidorchuk YV, Marenkova TV, Khozeeva SA, Kuznetsov VV, Zagorskaya AA, Rozov SM, Deineko EV. CRISPR/Cas9-mediated gfp gene inactivation in Arabidopsis suspension cells. Mol Biol Rep 2019; 46:5735-5743. [PMID: 31392536 DOI: 10.1007/s11033-019-05007-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 07/30/2019] [Indexed: 12/26/2022]
Abstract
Targeted genome editing using CRISPR/Cas9 is a promising technology successfully verified in various plant species; however, it has hardly been used in plant cell suspension cultures. Here, we describe a successful knockout of a green fluorescent protein (gfp) reporter gene in Arabidopsis cell culture. We transformed seven transgenic suspension cell lines carrying one to three gfp gene copies with a binary vector containing genes coding for Cas9 and guide RNAs targeting the gfp gene. We detected the site-specific mutations by restriction analysis of a gfp amplicon. DNA sequencing of the PCR products confirmed high diversity of insertion-deletion mutations in the cell lines after the editing. We also analyzed gfp mRNA expression by real-time PCR and observed a decrease in gfp transcription after the target site modification. We can conclude that the CRISPR/Cas9 system can be successfully used for introducing site-specific mutations into the genome of cultured suspension cells of Arabidopsis.
Collapse
Affiliation(s)
- Natalya V Permyakova
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, pr. Lavrentieva 10, Novosibirsk, Russia, 630090.
| | - Yury V Sidorchuk
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, pr. Lavrentieva 10, Novosibirsk, Russia, 630090
| | - Tatyana V Marenkova
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, pr. Lavrentieva 10, Novosibirsk, Russia, 630090
| | - Sofya A Khozeeva
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, pr. Lavrentieva 10, Novosibirsk, Russia, 630090
| | - Vitaly V Kuznetsov
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, pr. Lavrentieva 10, Novosibirsk, Russia, 630090
| | - Alla A Zagorskaya
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, pr. Lavrentieva 10, Novosibirsk, Russia, 630090
| | - Sergei M Rozov
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, pr. Lavrentieva 10, Novosibirsk, Russia, 630090
| | - Elena V Deineko
- Federal Research Center Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, pr. Lavrentieva 10, Novosibirsk, Russia, 630090
| |
Collapse
|
23
|
Kok EJ, Glandorf DC, Prins TW, Visser RG. Food and environmental safety assessment of new plant varieties after the European Court decision: Process-triggered or product-based? Trends Food Sci Technol 2019. [DOI: 10.1016/j.tifs.2019.03.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
|
24
|
Li J, Manghwar H, Sun L, Wang P, Wang G, Sheng H, Zhang J, Liu H, Qin L, Rui H, Li B, Lindsey K, Daniell H, Jin S, Zhang X. Whole genome sequencing reveals rare off-target mutations and considerable inherent genetic or/and somaclonal variations in CRISPR/Cas9-edited cotton plants. PLANT BIOTECHNOLOGY JOURNAL 2019; 17:858-868. [PMID: 30291759 PMCID: PMC6587709 DOI: 10.1111/pbi.13020] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 09/27/2018] [Accepted: 10/01/2018] [Indexed: 05/19/2023]
Abstract
The CRISPR/Cas9 system has been extensively applied for crop improvement. However, our understanding of Cas9 specificity is very limited in Cas9-edited plants. To identify on- and off-target mutation in an edited crop, we described whole genome sequencing (WGS) of 14 Cas9-edited cotton plants targeted to three genes, and three negative (Ne) control and three wild-type (WT) plants. In total, 4188-6404 unique single-nucleotide polymorphisms (SNPs) and 312-745 insertions/deletions (indels) were detected in 14 Cas9-edited plants compared to WT, negative and cotton reference genome sequences. Since the majority of these variations lack a protospacer-adjacent motif (PAM), we demonstrated that the most variations following Cas9-edited are due either to somaclonal variation or/and pre-existing/inherent variation from maternal plants, but not off-target effects. Of a total of 4413 potential off-target sites (allowing ≤5 mismatches within the 20-bp sgRNA and 3-bp PAM sequences), the WGS data revealed that only four are bona fide off-target indel mutations, validated by Sanger sequencing. Moreover, inherent genetic variation of WT can generate novel off-target sites and destroy PAMs, which suggested great care should be taken to design sgRNA for the minimizing of off-target effect. These findings suggested that CRISPR/Cas9 system is highly specific for cotton plants.
Collapse
Affiliation(s)
- Jianying Li
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubeiChina
| | - Hakim Manghwar
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubeiChina
| | - Lin Sun
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubeiChina
| | - Pengcheng Wang
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubeiChina
| | - Guanying Wang
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubeiChina
| | - Hanyan Sheng
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubeiChina
| | - Jie Zhang
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubeiChina
| | - Hao Liu
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubeiChina
- Agricultural Bioinformatics Key Laboratory of Hubei ProvinceCollege of InformaticsHuazhong Agricultural UniversityWuhanHubeiChina
| | - Lei Qin
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubeiChina
| | - Hangping Rui
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubeiChina
| | - Bo Li
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubeiChina
| | | | - Henry Daniell
- Department of BiochemistrySchool of Dental MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Shuangxia Jin
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubeiChina
| | - Xianlong Zhang
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanHubeiChina
| |
Collapse
|
25
|
Park D, Park SH, Kim YS, Choi BS, Kim JK, Kim NS, Choi IY. NGS sequencing reveals that many of the genetic variations in transgenic rice plants match the variations found in natural rice population. Genes Genomics 2018; 41:213-222. [PMID: 30406575 DOI: 10.1007/s13258-018-0754-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 10/15/2018] [Indexed: 11/27/2022]
Abstract
BACKGROUND As the transformation process can induce mutations in host plants, molecular characterization of the associated genomic changes is important not only for practical food safety but also for understanding the fundamental theories of genome evolution. OBJECTIVES To investigate a population-scale comparative study of the genome-wide spectrum of sequence variants in the transgenic genome with the variations present in 3000 rice varieties. RESULTS On average, we identified 19,273 SNPs (including Indels) per transgenic line in which 10,729 SNPs were at the identical locations in the three transgenic rice plants. We found that these variations were predominantly present in specific regions in chromosomes 8 and 10. Majority (88%) of the identified variations were detected at the same genomic locations as those in natural rice population, implying that the transgenic induced mutations had a tendency to be common alleles. CONCLUSION Genomic variations in transgenic rice plants frequently occurred at the same sites as the major alleles found in the natural rice population, which implies that the sequence variations occur within the limits of a biological system to ensure survival.
Collapse
Affiliation(s)
- Doori Park
- Department of Molecular Bioscience, Kangwon National University, Chuncheon, South Korea
| | - Su-Hyun Park
- Graduate School of International Agricultural Technology and Crop Biotech Institute/GreenBio Science and Technology, Seoul National University, Pyeongchang, South Korea
- Laboratory of Plant Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Youn Shic Kim
- Graduate School of International Agricultural Technology and Crop Biotech Institute/GreenBio Science and Technology, Seoul National University, Pyeongchang, South Korea
| | | | - Ju-Kon Kim
- Graduate School of International Agricultural Technology and Crop Biotech Institute/GreenBio Science and Technology, Seoul National University, Pyeongchang, South Korea.
| | - Nam-Soo Kim
- Department of Molecular Bioscience, Kangwon National University, Chuncheon, South Korea.
- Institute of Bioscience and Biomedical Sciences, Kangwon National University, Chuncheon, South Korea.
| | - Ik-Young Choi
- Department of Agriculture and Life Industry, Kangwon National University, Chuncheon, South Korea.
| |
Collapse
|
26
|
Partial maintenance of organ-specific epigenetic marks during plant asexual reproduction leads to heritable phenotypic variation. Proc Natl Acad Sci U S A 2018; 115:E9145-E9152. [PMID: 30201727 PMCID: PMC6166847 DOI: 10.1073/pnas.1805371115] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
While clonally propagated individuals should share identical genomes, there is often substantial phenotypic variation among them. Both genetic and epigenetic modifications induced during regeneration have been associated with this phenomenon. Here we investigated the fate of the epigenome after asexual propagation by generating clonal individuals from differentiated somatic cells through the manipulation of a zygotic transcription factor. We found that phenotypic novelty in clonal progeny was linked to epigenetic imprints that reflect the organ used for regeneration. Some of these organ-specific imprints can be maintained during the cloning process and subsequent rounds of meiosis. Our findings are fundamental for understanding the significance of epigenetic variability arising from asexual reproduction and have significant implications for future biotechnological applications. Plants differ from animals in their capability to easily regenerate fertile adult individuals from terminally differentiated cells. This unique developmental plasticity is commonly observed in nature, where many species can reproduce asexually through the ectopic initiation of organogenic or embryogenic developmental programs. While organ-specific epigenetic marks are not passed on during sexual reproduction, the fate of epigenetic marks during asexual reproduction and the implications for clonal progeny remain unclear. Here we report that organ-specific epigenetic imprints in Arabidopsis thaliana can be partially maintained during asexual propagation from somatic cells in which a zygotic program is artificially induced. The altered marks are inherited even over multiple rounds of sexual reproduction, becoming fixed in hybrids and resulting in heritable molecular and physiological phenotypes that depend on the identity of the founder tissue. Consequently, clonal plants display distinct interactions with beneficial and pathogenic microorganisms. Our results demonstrate how novel phenotypic variation in plants can be unlocked through altered inheritance of epigenetic marks upon asexual propagation.
Collapse
|
27
|
Michno JM, Stupar RM. The importance of genotype identity, genetic heterogeneity, and bioinformatic handling for properly assessing genomic variation in transgenic plants. BMC Biotechnol 2018; 18:38. [PMID: 29859067 PMCID: PMC5984819 DOI: 10.1186/s12896-018-0447-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 05/18/2018] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The advent of -omics technologies has enabled the resolution of fine molecular differences among individuals within a species. DNA sequence variations, such as single nucleotide polymorphisms or small deletions, can be tabulated for many kinds of genotype comparisons. However, experimental designs and analytical approaches are replete with ways to overestimate the level of variation present within a given sample. Analytical pipelines that do not apply proper thresholds nor assess reproducibility among samples are susceptible to calling false-positive variants. Furthermore, issues with sample genotype identity or failing to account for heterogeneity in reference genotypes may lead to misinterpretations of standing variants as polymorphisms derived de novo. RESULTS A recent publication that featured the analysis of RNA-sequencing data in three transgenic soybean event series appeared to overestimate the number of sequence variants identified in plants that were exposed to a tissue culture based transformation process. We reanalyzed these data with a stringent set of criteria and demonstrate three different factors that lead to variant overestimation, including issues related to the genetic identity of the background genotype, unaccounted genetic heterogeneity in the reference genome, and insufficient bioinformatics filtering. CONCLUSIONS This study serves as a cautionary tale to users of genomic and transcriptomic data that wish to assess the molecular variation attributable to tissue culture and transformation processes. Moreover, accounting for the factors that lead to sequence variant overestimation is equally applicable to samples derived from other germplasm sources, including chemical or irradiation mutagenesis and genome engineering (e.g., CRISPR) processes.
Collapse
Affiliation(s)
- Jean-Michel Michno
- Bioinformatics and Computational Biology Program, University of Minnesota, Minneapolis, MN USA
- Department of Agronomy and Plant Genetics, University of Minnesota, 1991 Upper Buford Circle, 411 Borlaug Hall, Saint Paul, MN 55108 USA
| | - Robert M. Stupar
- Bioinformatics and Computational Biology Program, University of Minnesota, Minneapolis, MN USA
- Department of Agronomy and Plant Genetics, University of Minnesota, 1991 Upper Buford Circle, 411 Borlaug Hall, Saint Paul, MN 55108 USA
| |
Collapse
|
28
|
Coronel CJ, González AI, Ruiz ML, Polanco C. Analysis of somaclonal variation in transgenic and regenerated plants of Arabidopsis thaliana using methylation related metAFLP and TMD markers. PLANT CELL REPORTS 2018; 37:137-152. [PMID: 29038910 DOI: 10.1007/s00299-017-2217-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/04/2017] [Indexed: 05/14/2023]
Abstract
We provide evidence that nucleotide sequence and methylation status changes occur in the Arabidopsis genome during in vitro tissue culture at a frequency high enough to represent an important source of variation. Somaclonal variation is a general consequence of the tissue culture process that has to be analyzed specifically when regenerated plants are obtained in any plant species. Currently, there are few studies about the variability comprising sequence changes and methylation status at the DNA level, generated by the culture of A. thaliana cells and tissues. In this work, two types of highly reproducible molecular markers, modified methylation sensitive AFLP (metAFLP) and transposon methylation display (TMD) have been used for the first time in this species to analyze the nucleotide and cytosine methylation changes induced by transformation and tissue culture protocols. We found significantly higher average methylation values (7.5%) in regenerated and transgenic plants when compared to values obtained from seed derived plants (3.2%) and that the main component of the somaclonal variation present in Arabidopsis clonal plants is genetic rather than epigenetic. However, we have found that the Arabidopsis regenerated and transgenic plants had a higher number of non-fully methylated sites flanking transposable elements than the control plants, and therefore, their mobilization can be facilitated. These data provide further evidence that changes in nucleotide sequence and methylation status occur in the Arabidopsis genome during in vitro tissue culture frequently enough to be an important source of variation in this species.
Collapse
Affiliation(s)
- Carlos J Coronel
- Área de Genética, Facultad de Ciencias Biológicas y Ambientales, Universidad de León, 24071, León, Spain
| | - Ana I González
- Área de Genética, Facultad de Ciencias Biológicas y Ambientales, Universidad de León, 24071, León, Spain
| | - María L Ruiz
- Área de Genética, Facultad de Ciencias Biológicas y Ambientales, Universidad de León, 24071, León, Spain
| | - Carlos Polanco
- Área de Genética, Facultad de Ciencias Biológicas y Ambientales, Universidad de León, 24071, León, Spain.
| |
Collapse
|
29
|
Belfield EJ, Ding ZJ, Jamieson FJC, Visscher AM, Zheng SJ, Mithani A, Harberd NP. DNA mismatch repair preferentially protects genes from mutation. Genome Res 2017; 28:66-74. [PMID: 29233924 PMCID: PMC5749183 DOI: 10.1101/gr.219303.116] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 11/20/2017] [Indexed: 01/11/2023]
Abstract
Mutation is the source of genetic variation and fuels biological evolution. Many mutations first arise as DNA replication errors. These errors subsequently evade correction by cellular DNA repair, for example, by the well-known DNA mismatch repair (MMR) mechanism. Here, we determine the genome-wide effects of MMR on mutation. We first identify almost 9000 mutations accumulated over five generations in eight MMR-deficient mutation accumulation (MA) lines of the model plant species, Arabidopsis thaliana. We then show that MMR deficiency greatly increases the frequency of both smaller-scale insertions and deletions (indels) and of single-nucleotide variant (SNV) mutations. Most indels involve A or T nucleotides and occur preferentially in homopolymeric (poly A or poly T) genomic stretches. In addition, we find that the likelihood of occurrence of indels in homopolymeric stretches is strongly related to stretch length, and that this relationship causes ultrahigh localized mutation rates in specific homopolymeric stretch regions. For SNVs, we show that MMR deficiency both increases their frequency and changes their molecular mutational spectrum, causing further enhancement of the GC to AT bias characteristic of organisms with normal MMR function. Our final genome-wide analyses show that MMR deficiency disproportionately increases the numbers of SNVs in genes, rather than in nongenic regions of the genome. This latter observation indicates that MMR preferentially protects genes from mutation and has important consequences for understanding the evolution of genomes during both natural selection and human tumor growth.
Collapse
Affiliation(s)
- Eric J Belfield
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| | - Zhong Jie Ding
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Fiona J C Jamieson
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| | - Anne M Visscher
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom.,Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew, Wakehurst Place, Ardingly, West Sussex RH17 6TN, United Kingdom
| | - Shao Jian Zheng
- State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Aziz Mithani
- Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences (LUMS), DHA, Lahore 54792, Pakistan
| | - Nicholas P Harberd
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| |
Collapse
|
30
|
Díaz-Castillo C. Transcriptome dynamics along axolotl regenerative development are consistent with an extensive reduction in gene expression heterogeneity in dedifferentiated cells. PeerJ 2017; 5:e4004. [PMID: 29134148 PMCID: PMC5678507 DOI: 10.7717/peerj.4004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 10/18/2017] [Indexed: 12/13/2022] Open
Abstract
Although in recent years the study of gene expression variation in the absence of genetic or environmental cues or gene expression heterogeneity has intensified considerably, many basic and applied biological fields still remain unaware of how useful the study of gene expression heterogeneity patterns might be for the characterization of biological systems and/or processes. Largely based on the modulator effect chromatin compaction has for gene expression heterogeneity and the extensive changes in chromatin compaction known to occur for specialized cells that are naturally or artificially induced to revert to less specialized states or dedifferentiate, I recently hypothesized that processes that concur with cell dedifferentiation would show an extensive reduction in gene expression heterogeneity. The confirmation of the existence of such trend could be of wide interest because of the biomedical and biotechnological relevance of cell dedifferentiation-based processes, i.e., regenerative development, cancer, human induced pluripotent stem cells, or plant somatic embryogenesis. Here, I report the first empirical evidence consistent with the existence of an extensive reduction in gene expression heterogeneity for processes that concur with cell dedifferentiation by analyzing transcriptome dynamics along forearm regenerative development in Ambystoma mexicanum or axolotl. Also, I briefly discuss on the utility of the study of gene expression heterogeneity dynamics might have for the characterization of cell dedifferentiation-based processes, and the engineering of tools that afforded better monitoring and modulating such processes. Finally, I reflect on how a transitional reduction in gene expression heterogeneity for dedifferentiated cells can promote a long-term increase in phenotypic heterogeneity following cell dedifferentiation with potential adverse effects for biomedical and biotechnological applications.
Collapse
|
31
|
Li S, Zheng YC, Cui HR, Fu HW, Shu QY, Huang JZ. Frequency and type of inheritable mutations induced by γ rays in rice as revealed by whole genome sequencing. J Zhejiang Univ Sci B 2017; 17:905-915. [PMID: 27921396 DOI: 10.1631/jzus.b1600125] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mutation breeding is based on the induction of genetic variations; hence knowledge of the frequency and type of induced mutations is of paramount importance for the design and implementation of a mutation breeding program. Although γ ray irradiation has been widely used since the 1960s in the breeding of about 200 economically important plant species, molecular elucidation of its genetic effects has so far been achieved largely by analysis of target genes or genomic regions. In the present study, the whole genomes of six γ-irradiated M2 rice plants were sequenced; a total of 144-188 million high-quality (Q>20) reads were generated for each M2 plant, resulting in genome coverage of >45 times for each plant. Single base substitution (SBS) and short insertion/deletion (Indel) mutations were detected at the average frequency of 7.5×10-6-9.8×10-6 in the six M2 rice plants (SBS being about 4 times more frequent than Indels). Structural and copy number variations, though less frequent than SBS and Indel, were also identified and validated. The mutations were scattered in all genomic regions across 12 rice chromosomes without apparent hotspots. The present study is the first genome-wide single-nucleotide resolution study on the feature and frequency of γ irradiation-induced mutations in a seed propagated crop; the findings are of practical importance for mutation breeding of rice and other crop species.
Collapse
Affiliation(s)
- Shan Li
- National Key Laboratory of Rice Biology, Institute of Crop Sciences, Zhejiang University, Hangzhou 310058, China.,Institute of Nuclear Agricultural Sciences, Zhejiang University, Hangzhou 310029, China
| | - Yun-Chao Zheng
- National Key Laboratory of Rice Biology, Institute of Crop Sciences, Zhejiang University, Hangzhou 310058, China.,Hubei Collaborative Innovation Center for Grain Industry, Jingzhou 434025, China
| | - Hai-Rui Cui
- Institute of Nuclear Agricultural Sciences, Zhejiang University, Hangzhou 310029, China
| | - Hao-Wei Fu
- Jiaxing Academy of Agricultural Sciences, Jiaxing 314016, China
| | - Qing-Yao Shu
- National Key Laboratory of Rice Biology, Institute of Crop Sciences, Zhejiang University, Hangzhou 310058, China.,Hubei Collaborative Innovation Center for Grain Industry, Jingzhou 434025, China
| | - Jian-Zhong Huang
- National Key Laboratory of Rice Biology, Institute of Crop Sciences, Zhejiang University, Hangzhou 310058, China.,Institute of Nuclear Agricultural Sciences, Zhejiang University, Hangzhou 310029, China
| |
Collapse
|
32
|
Dolgikh YI, Solov’yova AI, Tereshonok DV. Variability of DNA markers in Arabidopsis thaliana cultured cells under standard growing conditions and under the influence of stressors. BIOL BULL+ 2017. [DOI: 10.1134/s1062359017020042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
33
|
Schouten HJ, Vande Geest H, Papadimitriou S, Bemer M, Schaart JG, Smulders MJM, Perez GS, Schijlen E. Re-sequencing transgenic plants revealed rearrangements at T-DNA inserts, and integration of a short T-DNA fragment, but no increase of small mutations elsewhere. PLANT CELL REPORTS 2017; 36:493-504. [PMID: 28155116 PMCID: PMC5316556 DOI: 10.1007/s00299-017-2098-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 01/02/2017] [Indexed: 05/05/2023]
Abstract
KEY MESSAGE Transformation resulted in deletions and translocations at T-DNA inserts, but not in genome-wide small mutations. A tiny T-DNA splinter was detected that probably would remain undetected by conventional techniques. We investigated to which extent Agrobacterium tumefaciens-mediated transformation is mutagenic, on top of inserting T-DNA. To prevent mutations due to in vitro propagation, we applied floral dip transformation of Arabidopsis thaliana. We re-sequenced the genomes of five primary transformants, and compared these to genomic sequences derived from a pool of four wild-type plants. By genome-wide comparisons, we identified ten small mutations in the genomes of the five transgenic plants, not correlated to the positions or number of T-DNA inserts. This mutation frequency is within the range of spontaneous mutations occurring during seed propagation in A. thaliana, as determined earlier. In addition, we detected small as well as large deletions specifically at the T-DNA insert sites. Furthermore, we detected partial T-DNA inserts, one of these a tiny 50-bp fragment originating from a central part of the T-DNA construct used, inserted into the plant genome without flanking other T-DNA. Because of its small size, we named this fragment a T-DNA splinter. As far as we know this is the first report of such a small T-DNA fragment insert in absence of any T-DNA border sequence. Finally, we found evidence for translocations from other chromosomes, flanking T-DNA inserts. In this study, we showed that next-generation sequencing (NGS) is a highly sensitive approach to detect T-DNA inserts in transgenic plants.
Collapse
Affiliation(s)
- Henk J Schouten
- Plant Breeding, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
| | - Henri Vande Geest
- Business Unit Bioscience, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Sofia Papadimitriou
- Business Unit Bioscience, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Marian Bemer
- Business Unit Bioscience, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Jan G Schaart
- Plant Breeding, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Marinus J M Smulders
- Plant Breeding, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Gabino Sanchez Perez
- Business Unit Bioscience, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| | - Elio Schijlen
- Business Unit Bioscience, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands
| |
Collapse
|
34
|
Masuta Y, Nozawa K, Takagi H, Yaegashi H, Tanaka K, Ito T, Saito H, Kobayashi H, Matsunaga W, Masuda S, Kato A, Ito H. Inducible Transposition of a Heat-Activated Retrotransposon in Tissue Culture. PLANT & CELL PHYSIOLOGY 2017; 58:375-384. [PMID: 28013279 DOI: 10.1093/pcp/pcw202] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 11/14/2016] [Indexed: 06/06/2023]
Abstract
A transposition of a heat-activated retrotransposon named ONSEN required compromise of a small RNA-mediated epigenetic regulation that includes RNA-directed DNA methylation (RdDM) machinery after heat treatment. In the current study, we analyzed the transcriptional and transpositional activation of ONSEN to better understand the underlying molecular mechanism involved in the maintenance and/or induction of transposon activation in plant tissue culture. We found the transposition of heat-primed ONSEN during tissue culture independently of RdDM mutation. The heat activation of ONSEN transcripts was not significantly up-regulated in tissue culture compared with that in heat-stressed seedlings, indicating that the transposition of ONSEN was regulated independently of the transcript level. RdDM-related genes were up-regulated by heat stress in both tissue culture and seedlings. The level of DNA methylation of ONSEN did not show any change in tissue culture, and the amount of ONSEN-derived small RNAs was not affected by heat stress. The results indicated that the transposition of ONSEN was regulated by an alternative mechanism in addition to the RdDM-mediated epigenetic regulation in tissue culture. We applied the tissue culture-induced transposition of ONSEN to Japanese radish, an important breeding species of the family Brassicaceae. Several new insertions were detected in a regenerated plant derived from heat-stressed tissues and its self-fertilized progeny, revealing the possibility of molecular breeding without genetic modification.
Collapse
Affiliation(s)
- Yukari Masuta
- Faculty of Science, Hokkaido University, Sappor, Japan
| | - Kosuke Nozawa
- Faculty of Science, Hokkaido University, Sappor, Japan
| | | | | | - Keisuke Tanaka
- NODAI Genome Research Center, Tokyo University of Agriculture, Tokyo, Japan
| | - Tasuku Ito
- Center for Ecological Research, Kyoto University, Otsu, Japan
| | - Hideyuki Saito
- Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Hisato Kobayashi
- NODAI Genome Research Center, Tokyo University of Agriculture, Tokyo, Japan
| | | | - Seiji Masuda
- Faculty of Science, Hokkaido University, Sappor, Japan
| | - Atsushi Kato
- Faculty of Science, Hokkaido University, Sappor, Japan
| | - Hidetaka Ito
- Faculty of Science, Hokkaido University, Sappor, Japan
| |
Collapse
|
35
|
Anderson JE, Michno JM, Kono TJY, Stec AO, Campbell BW, Curtin SJ, Stupar RM. Genomic variation and DNA repair associated with soybean transgenesis: a comparison to cultivars and mutagenized plants. BMC Biotechnol 2016; 16:41. [PMID: 27176220 PMCID: PMC4866027 DOI: 10.1186/s12896-016-0271-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 05/04/2016] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The safety of mutagenized and genetically transformed plants remains a subject of scrutiny. Data gathered and communicated on the phenotypic and molecular variation induced by gene transfer technologies will provide a scientific-based means to rationally address such concerns. In this study, genomic structural variation (e.g. large deletions and duplications) and single nucleotide polymorphism rates were assessed among a sample of soybean cultivars, fast neutron-derived mutants, and five genetically transformed plants developed through Agrobacterium based transformation methods. RESULTS On average, the number of genes affected by structural variations in transgenic plants was one order of magnitude less than that of fast neutron mutants and two orders of magnitude less than the rates observed between cultivars. Structural variants in transgenic plants, while rare, occurred adjacent to the transgenes, and at unlinked loci on different chromosomes. DNA repair junctions at both transgenic and unlinked sites were consistent with sequence microhomology across breakpoints. The single nucleotide substitution rates were modest in both fast neutron and transformed plants, exhibiting fewer than 100 substitutions genome-wide, while inter-cultivar comparisons identified over one-million single nucleotide polymorphisms. CONCLUSIONS Overall, these patterns provide a fresh perspective on the genomic variation associated with high-energy induced mutagenesis and genetically transformed plants. The genetic transformation process infrequently results in novel genetic variation and these rare events are analogous to genetic variants occurring spontaneously, already present in the existing germplasm, or induced through other types of mutagenesis. It remains unclear how broadly these results can be applied to other crops or transformation methods.
Collapse
Affiliation(s)
- Justin E Anderson
- Department of Agronomy & Plant Genetics, University of Minnesota, 1991 Upper Buford Circle, 411 Borlaug Hall, St. Paul, MN 55108, USA
| | - Jean-Michel Michno
- Department of Agronomy & Plant Genetics, University of Minnesota, 1991 Upper Buford Circle, 411 Borlaug Hall, St. Paul, MN 55108, USA
| | - Thomas J Y Kono
- Department of Agronomy & Plant Genetics, University of Minnesota, 1991 Upper Buford Circle, 411 Borlaug Hall, St. Paul, MN 55108, USA
| | - Adrian O Stec
- Department of Agronomy & Plant Genetics, University of Minnesota, 1991 Upper Buford Circle, 411 Borlaug Hall, St. Paul, MN 55108, USA
| | - Benjamin W Campbell
- Department of Agronomy & Plant Genetics, University of Minnesota, 1991 Upper Buford Circle, 411 Borlaug Hall, St. Paul, MN 55108, USA
| | - Shaun J Curtin
- Department of Agronomy & Plant Genetics, University of Minnesota, 1991 Upper Buford Circle, 411 Borlaug Hall, St. Paul, MN 55108, USA
| | - Robert M Stupar
- Department of Agronomy & Plant Genetics, University of Minnesota, 1991 Upper Buford Circle, 411 Borlaug Hall, St. Paul, MN 55108, USA.
| |
Collapse
|
36
|
Wei FJ, Kuang LY, Oung HM, Cheng SY, Wu HP, Huang LT, Tseng YT, Chiou WY, Hsieh-Feng V, Chung CH, Yu SM, Lee LY, Gelvin SB, Hsing YIC. Somaclonal variation does not preclude the use of rice transformants for genetic screening. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 85:648-59. [PMID: 26833589 DOI: 10.1111/tpj.13132] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 12/21/2015] [Accepted: 01/20/2016] [Indexed: 05/07/2023]
Abstract
Rice (Oryza sativa) is one of the world's most important crops. Rice researchers make extensive use of insertional mutants for the study of gene function. Approximately half a million flanking sequence tags from rice insertional mutant libraries are publicly available. However, the relationship between genotype and phenotype is very weak. Transgenic plant assays have been used frequently for complementation, overexpression or antisense analysis, but sequence changes caused by callus growth, Agrobacterium incubation medium, virulence genes, transformation and selection conditions are unknown. We used high-throughput sequencing of DNA from rice lines derived from Tainung 67 to analyze non-transformed and transgenic rice plants for mutations caused by these parameters. For comparison, we also analyzed sequence changes for two additional rice varieties and four T-DNA tagged transformants from the Taiwan Rice Insertional Mutant resource. We identified single-nucleotide polymorphisms, small indels, large deletions, chromosome doubling and chromosome translocations in these lines. Using standard rice regeneration/transformation procedures, the mutation rates of regenerants and transformants were relatively low, with no significant differences among eight tested treatments in the Tainung 67 background and in the cultivars Taikeng 9 and IR64. Thus, we could not conclusively detect sequence changes resulting from Agrobacterium-mediated transformation in addition to those caused by tissue culture-induced somaclonal variation. However, the mutation frequencies within the two publically available tagged mutant populations, including TRIM transformants or Tos17 lines, were about 10-fold higher than the frequency of standard transformants, probably because mass production of embryogenic calli and longer callus growth periods were required to generate these large libraries.
Collapse
Affiliation(s)
- Fu-Jin Wei
- Institute of Plant and Microbial Biology, Academia Sinica, No. 128, Section 2, Yien-Chu-Yuan Road, Taipei, 11529, Taiwan
- Department of Agronomy, National Taiwan University, No. 1, Section 4, Roosevelt Rd, Taipei, 10617, Taiwan
| | - Lin-Yun Kuang
- Transgenic Plant Core Facility, Academia Sinica, No. 128, Section 2, Yien-Chu-Yuan Road, Taipei, 11529, Taiwan
| | - Hui-Min Oung
- Institute of Plant and Microbial Biology, Academia Sinica, No. 128, Section 2, Yien-Chu-Yuan Road, Taipei, 11529, Taiwan
| | - Sin-Yuan Cheng
- Institute of Plant and Microbial Biology, Academia Sinica, No. 128, Section 2, Yien-Chu-Yuan Road, Taipei, 11529, Taiwan
| | - Hshin-Ping Wu
- Institute of Plant and Microbial Biology, Academia Sinica, No. 128, Section 2, Yien-Chu-Yuan Road, Taipei, 11529, Taiwan
| | - Lin-Tzu Huang
- Institute of Plant and Microbial Biology, Academia Sinica, No. 128, Section 2, Yien-Chu-Yuan Road, Taipei, 11529, Taiwan
| | - Yi-Tzu Tseng
- Institute of Plant and Microbial Biology, Academia Sinica, No. 128, Section 2, Yien-Chu-Yuan Road, Taipei, 11529, Taiwan
- Institute of Plant Biology, National Taiwan University, No. 1, Section 4, Roosevelt Rd, Taipei, 10617, Taiwan
| | - Wan-Yi Chiou
- Institute of Plant and Microbial Biology, Academia Sinica, No. 128, Section 2, Yien-Chu-Yuan Road, Taipei, 11529, Taiwan
| | - Vicki Hsieh-Feng
- Department of Agronomy, National Taiwan University, No. 1, Section 4, Roosevelt Rd, Taipei, 10617, Taiwan
| | - Cheng-Han Chung
- Institute of Plant and Microbial Biology, Academia Sinica, No. 128, Section 2, Yien-Chu-Yuan Road, Taipei, 11529, Taiwan
| | - Su-May Yu
- Institute of Molecular Biology, Academia Sinica, No. 128, Section 2, Yien-Chu-Yuan Road, Taipei, 11529, Taiwan
| | - Lan-Ying Lee
- Department of Biological Sciences, Purdue University, 201 South University St., West Lafayette, IN, 47907-1392, USA
| | - Stanton B Gelvin
- Department of Biological Sciences, Purdue University, 201 South University St., West Lafayette, IN, 47907-1392, USA
| | - Yue-Ie C Hsing
- Institute of Plant and Microbial Biology, Academia Sinica, No. 128, Section 2, Yien-Chu-Yuan Road, Taipei, 11529, Taiwan
| |
Collapse
|
37
|
Dubrovina AS, Kiselev KV. Age-associated alterations in the somatic mutation and DNA methylation levels in plants. PLANT BIOLOGY (STUTTGART, GERMANY) 2016; 18:185-196. [PMID: 26211365 DOI: 10.1111/plb.12375] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 07/21/2015] [Indexed: 05/18/2023]
Abstract
Somatic mutations of the nuclear and mitochondrial DNA and alterations in DNA methylation levels in mammals are well known to play important roles in ageing and various diseases, yet their specific contributions await further investigation. For plants, it has also been proposed that unrepaired DNA damage and DNA polymerase errors accumulate in plant cells and lead to increased somatic mutation rate and alterations in transcription, which eventually contribute to plant ageing. A number of studies also show that DNA methylation levels vary depending on the age of plant tissue and chronological age of a whole plant. Recent studies reveal that prolonged cultivation of plant cells in vitro induces single nucleotide substitutions and increases global DNA methylation level in a time-dependent fashion. Changes in DNA methylation are known to influence DNA repair and can lead to altered mutation rates, and, therefore, it is interesting to investigate both the genetic and epigenetic integrity in relationship to ageing in plants. This review will summarise and discuss the current studies investigating somatic DNA mutation and DNA methylation levels in relation to plant ageing and senescence. The analysis has shown that there still remains a lack of clarity concerning plant biological ageing and the role of the genetic and epigenetic instabilities in this process.
Collapse
Affiliation(s)
- A S Dubrovina
- Laboratory of Biotechnology, Institute of Biology and Soil Science, Far East Branch of Russian Academy of Sciences, Vladivostok, Russia
| | - K V Kiselev
- Laboratory of Biotechnology, Institute of Biology and Soil Science, Far East Branch of Russian Academy of Sciences, Vladivostok, Russia
- Department of Biochemistry, Microbiology and Biotechnology, The School of Natural Sciences, Far Eastern Federal University, Vladivostok, Russia
| |
Collapse
|
38
|
Abstract
AbstractPlant tissue culture techniques have become an integral part of progress in plant science research due to the opportunity offered for close study of detailed plant development with applications in food production through crop improvement, secondary metabolites production and conservation of species. Because the techniques involve growing plants under controlled conditions different from their natural outdoor environment, the plants need adjustments in physiology, anatomy and metabolism for successfulin vitropropagation. Therefore, the protocol has to be optimized for a given species or genotype due to the variability in physiological and growth requirement. Developing the protocol is hampered by several physiological and developmental aberrations in the anatomy and physiology of the plantlets, attributed toin vitroculture conditions of high humidity, low light levels and hetero- or mixotrophic conditions. Some of the culture-induced anomalies become genetic, and the phenotype is inherited by clonal progenies while others are temporary and can be corrected at a later stage of protocol development through changes in anatomy, physiology and metabolism. The success of protocols relies on the transfer of plantlets to field conditions which has been achieved with many species through stages of acclimatization, while with others it remains a challenging task. This review discusses various adjustments in nutrition, physiology and anatomy of micro-propagated plants and field grown ones, as well as anomalies induced by thein vitroculture conditions.
Collapse
|
39
|
Grandbastien MA. LTR retrotransposons, handy hitchhikers of plant regulation and stress response. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2015; 1849:403-16. [DOI: 10.1016/j.bbagrm.2014.07.017] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 07/21/2014] [Accepted: 07/23/2014] [Indexed: 11/30/2022]
|
40
|
Li X, Scanlon MJ, Yu J. Evolutionary patterns of DNA base composition and correlation to polymorphisms in DNA repair systems. Nucleic Acids Res 2015; 43:3614-25. [PMID: 25765652 PMCID: PMC4402523 DOI: 10.1093/nar/gkv197] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 02/24/2015] [Indexed: 11/15/2022] Open
Abstract
DNA base composition is a fundamental genome feature. However, the evolutionary pattern of base composition and its potential causes have not been well understood. Here, we report findings from comparative analysis of base composition at the whole-genome level across 2210 species, the polymorphic-site level across eight population comparison sets, and the mutation-site level in 12 mutation-tracking experiments. We first demonstrate that base composition follows the individual-strand base equality rule at the genome, chromosome and polymorphic-site levels. More intriguingly, clear separation of base-composition values calculated across polymorphic sites was consistently observed between basal and derived groups, suggesting common underlying mechanisms. Individuals in the derived groups show an A&T-increase/G&C-decrease pattern compared with the basal groups. Spontaneous and induced mutation experiments indicated these patterns of base composition change can emerge across mutation sites. With base-composition across polymorphic sites as a genome phenotype, genome scans with human 1000 Genomes and HapMap3 data identified a set of significant genomic regions enriched with Gene Ontology terms for DNA repair. For three DNA repair genes (BRIP1, PMS2P3 and TTDN), ENCODE data provided evidence for interaction between genomic regions containing these genes and regions containing the significant SNPs. Our findings provide insights into the mechanisms of genome evolution.
Collapse
Affiliation(s)
- Xianran Li
- Department of Agronomy, Iowa State University, Ames, IA 50011, USA
| | - Michael J Scanlon
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - Jianming Yu
- Department of Agronomy, Iowa State University, Ames, IA 50011, USA
| |
Collapse
|
41
|
Sedov KA, Fomenkov AA, Solov’yova AI, Nosov AV, Dolgikh YI. The level of genetic variability of cells in prolonged suspension culture of Arabidopsis thaliana. BIOL BULL+ 2014. [DOI: 10.1134/s1062359014060107] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
42
|
Schnell J, Steele M, Bean J, Neuspiel M, Girard C, Dormann N, Pearson C, Savoie A, Bourbonnière L, Macdonald P. A comparative analysis of insertional effects in genetically engineered plants: considerations for pre-market assessments. Transgenic Res 2014; 24:1-17. [PMID: 25344849 PMCID: PMC4274372 DOI: 10.1007/s11248-014-9843-7] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 10/16/2014] [Indexed: 01/20/2023]
Abstract
During genetic engineering, DNA is inserted into a plant’s genome, and such insertions are often accompanied by the insertion of additional DNA, deletions and/or rearrangements. These genetic changes are collectively known as insertional effects, and they have the potential to give rise to unintended traits in plants. In addition, there are many other genetic changes that occur in plants both spontaneously and as a result of conventional breeding practices. Genetic changes similar to insertional effects occur in plants, namely as a result of the movement of transposable elements, the repair of double-strand breaks by non-homologous end-joining, and the intracellular transfer of organelle DNA. Based on this similarity, insertional effects should present a similar level of risk as these other genetic changes in plants, and it is within the context of these genetic changes that insertional effects must be considered. Increased familiarity with genetic engineering techniques and advances in molecular analysis techniques have provided us with a greater understanding of the nature and impact of genetic changes in plants, and this can be used to refine pre-market assessments of genetically engineered plants and food and feeds derived from genetically engineered plants.
Collapse
Affiliation(s)
- Jaimie Schnell
- Plant and Biotechnology Risk Assessment Unit, Canadian Food Inspection Agency, 1400 Merivale Road, Ottawa, ON, K1A 0Y9, Canada,
| | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Environmentally responsive genome-wide accumulation of de novo Arabidopsis thaliana mutations and epimutations. Genome Res 2014; 24:1821-9. [PMID: 25314969 PMCID: PMC4216923 DOI: 10.1101/gr.177659.114] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Evolution is fueled by phenotypic diversity, which is in turn due to underlying heritable genetic (and potentially epigenetic) variation. While environmental factors are well known to influence the accumulation of novel variation in microorganisms and human cancer cells, the extent to which the natural environment influences the accumulation of novel variation in plants is relatively unknown. Here we use whole-genome and whole-methylome sequencing to test if a specific environmental stress (high-salinity soil) changes the frequency and molecular profile of accumulated mutations and epimutations (changes in cytosine methylation status) in mutation accumulation (MA) lineages of Arabidopsis thaliana. We first show that stressed lineages accumulate ∼100% more mutations, and that these mutations exhibit a distinctive molecular mutational spectrum (specific increases in relative frequency of transversion and insertion/deletion [indel] mutations). We next show that stressed lineages accumulate ∼45% more differentially methylated cytosine positions (DMPs) at CG sites (CG-DMPs) than controls, and also show that while many (∼75%) of these CG-DMPs are inherited, some can be lost in subsequent generations. Finally, we show that stress-associated CG-DMPs arise more frequently in genic than in nongenic regions of the genome. We suggest that commonly encountered natural environmental stresses can accelerate the accumulation and change the profiles of novel inherited variants in plants. Our findings are significant because stress exposure is common among plants in the wild, and they suggest that environmental factors may significantly alter the rates and patterns of incidence of the inherited novel variants that fuel plant evolution.
Collapse
|
44
|
Zhang D, Wang Z, Wang N, Gao Y, Liu Y, Wu Y, Bai Y, Zhang Z, Lin X, Dong Y, Ou X, Xu C, Liu B. Tissue culture-induced heritable genomic variation in rice, and their phenotypic implications. PLoS One 2014; 9:e96879. [PMID: 24804838 PMCID: PMC4013045 DOI: 10.1371/journal.pone.0096879] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 04/12/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Somaclonal variation generally occurs in plants regenerated from tissue culture. However, fundamental issues regarding molecular characteristics, mutation rates and mutation spectra of plant somatic variation as well as their phenotypic relevance have been addressed only recently. Moreover, these studies have reported highly discrepant results in different plant species and even in the same plant genotype. METHODOLOGY/PRINCIPAL FINDINGS We investigated heritable genomic variation induced by tissue culture in rice by whole genome re-sequencing of an extensively selfed somaclonal line (TC-reg-2008) and its wild type (WT) donor (cv. Hitomebore). We computed the overall mutation rate, single nucleotide polymorphisms (SNPs), small scale insertions/deletions (Indels) and mobilization of transposable elements (TEs). We assessed chromosomal distribution of the various types of genomic variations, tested correlations between SNPs and Indels, and examined concomitancy between TE activity and its cytosine methylation states. We also performed gene ontology (GO) analysis of genes containing nonsynonymous mutations and large-effect mutations, and assayed effects of the genomic variations on phenotypes under both normal growing condition and several abiotic stresses. We found that heritable somaclonal genomic variation occurred extensively in rice. The genomic variations distributed non-randomly across each of the 12 rice chromosomes, and affected a large number of functional genes. The phenotypic penetrance of the genomic variations was condition-dependent. CONCLUSIONS/SIGNIFICANCE Tissue culture is a potent means to generate heritable genetic variations in rice, which bear distinct difference at least in space (chromosomal distribution) from those occurred under natural settings. Our findings have provided new information regarding the mutation rate and spectrum as well as chromosomal distribution pattern of somaclonal variation in rice. Our data also suggest that rice possesses a strong capacity to canalize genetic variations under normal growing conditions to maintain phenotypic robustness, which however can be released by certain abiotic stresses to generate variable phenotypes.
Collapse
Affiliation(s)
- Di Zhang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Zhenhui Wang
- Faculty of Agronomy, Jilin Agricultural University, Changchun, China
| | - Ningning Wang
- Faculty of Agronomy, Jilin Agricultural University, Changchun, China
| | - Yang Gao
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Ying Liu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Ying Wu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Yan Bai
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Zhibin Zhang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Xiuyun Lin
- Jilin Academy of Agricultural Sciences, Changchun, China
| | - Yuzhu Dong
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Xiufang Ou
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Chunming Xu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| | - Bao Liu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, China
| |
Collapse
|
45
|
Hopkins MT, Khalid AM, Chang PC, Vanderhoek KC, Lai D, Doerr MD, Lolle SJ. De novo genetic variation revealed in somatic sectors of single Arabidopsis plants. F1000Res 2014; 2:5. [PMID: 24555023 PMCID: PMC3894806 DOI: 10.12688/f1000research.2-5.v2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/29/2013] [Indexed: 12/17/2022] Open
Abstract
Concern over the tremendous loss of genetic diversity among many of our most important crops has prompted major efforts to preserve seed stocks derived from cultivated species and their wild relatives.
Arabidopsis thaliana propagates mainly by self-fertilizing, and therefore, like many crop plants, theoretically has a limited potential for producing genetically diverse offspring. Despite this, inbreeding has persisted in Arabidopsis for over a million years suggesting that some underlying adaptive mechanism buffers the deleterious consequences of this reproductive strategy. Using presence-absence molecular markers we demonstrate that single Arabidopsis plants can have multiple genotypes. Sequence analyses reveal single nucleotide changes, loss of sequences and, surprisingly, acquisition of unique genomic insertions. Estimates based on quantitative analyses suggest that these genetically discordant sectors are very small but can have a complex genetic makeup. In ruling out more trivial explanations for these data, our findings raise the possibility that intrinsic drivers of genetic variation are responsible for the targeted sequence changes we detect. Given the evolutionary advantage afforded to populations with greater genetic diversity, we hypothesize that organisms that primarily self-fertilize or propagate clonally counteract the genetic cost of such reproductive strategies by leveraging a cryptic reserve of extra-genomic information.
Collapse
Affiliation(s)
- Marianne T Hopkins
- Department of Biology, University of Waterloo, Waterloo, N2L 3G1, Canada
| | - Aaron M Khalid
- Department of Biology, University of Waterloo, Waterloo, N2L 3G1, Canada
| | - Pei-Chun Chang
- Department of Biology, University of Waterloo, Waterloo, N2L 3G1, Canada
| | - Karen C Vanderhoek
- Department of Biology, University of Waterloo, Waterloo, N2L 3G1, Canada
| | - Dulcie Lai
- Department of Pathology and Molecular Medicine, Queen's University, Kingston, K7L 3N6, Canada
| | - Meghan D Doerr
- Department of Biology, University of Waterloo, Waterloo, N2L 3G1, Canada
| | - Susan J Lolle
- Department of Biology, University of Waterloo, Waterloo, N2L 3G1, Canada
| |
Collapse
|
46
|
Kawakatsu T, Kawahara Y, Itoh T, Takaiwa F. A whole-genome analysis of a transgenic rice seed-based edible vaccine against cedar pollen allergy. DNA Res 2013; 20:623-31. [PMID: 23956243 PMCID: PMC3859328 DOI: 10.1093/dnares/dst036] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Genetic modification (GM) by Agrobacterium-mediated transformation is a robust and widely employed method to confer new traits to crops. In this process, a transfer DNA is delivered into the host genome, but it is still unclear how the host genome is altered by this event at single-base resolution. To decipher genomic discrepancy between GM crops and their host, we conducted whole-genome sequencing of a transgenic rice line OSCR11. This rice line expresses a seed-based edible vaccine containing two major pollen allergens, Cry j 1 and Cry j 2, against Japanese cedar pollinosis. We revealed that genetic differences between OSCR11 and its host a123 were significantly less than those between a123 and its precedent cultivar Koshihikari. The pattern of nucleotide base substitution in OSCR11, relative to a123, was consistent with somaclonal variation. Mutations in OSCR11 probably occurred during the cell culture steps. In addition, strand-specific mRNA-Seq revealed similar transcriptomes of a123 and OSCR11, supporting genomic integrity between them.
Collapse
Affiliation(s)
- Taiji Kawakatsu
- 1Genetically Modified Organism Research Center, National Institute of Agrobiological Sciences, 2-1-2 Kan-nondai, Tsukuba, Ibaraki 305-8602, Japan
| | | | | | | |
Collapse
|
47
|
Vining K, Pomraning KR, Wilhelm LJ, Ma C, Pellegrini M, Di Y, Mockler TC, Freitag M, Strauss SH. Methylome reorganization during in vitro dedifferentiation and regeneration of Populus trichocarpa. BMC PLANT BIOLOGY 2013; 13:92. [PMID: 23799904 PMCID: PMC3728041 DOI: 10.1186/1471-2229-13-92] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 06/12/2013] [Indexed: 05/22/2023]
Abstract
BACKGROUND Cytosine DNA methylation (5mC) is an epigenetic modification that is important to genome stability and regulation of gene expression. Perturbations of 5mC have been implicated as a cause of phenotypic variation among plants regenerated through in vitro culture systems. However, the pattern of change in 5mC and its functional role with respect to gene expression, are poorly understood at the genome scale. A fuller understanding of how 5mC changes during in vitro manipulation may aid the development of methods for reducing or amplifying the mutagenic and epigenetic effects of in vitro culture and plant transformation. RESULTS We investigated the in vitro methylome of the model tree species Populus trichocarpa in a system that mimics routine methods for regeneration and plant transformation in the genus Populus (poplar). Using methylated DNA immunoprecipitation followed by high-throughput sequencing (MeDIP-seq), we compared the methylomes of internode stem segments from micropropagated explants, dedifferentiated calli, and internodes from regenerated plants. We found that more than half (56%) of the methylated portion of the genome appeared to be differentially methylated among the three tissue types. Surprisingly, gene promoter methylation varied little among tissues, however, the percentage of body-methylated genes increased from 9% to 14% between explants and callus tissue, then decreased to 8% in regenerated internodes. Forty-five percent of differentially-methylated genes underwent transient methylation, becoming methylated in calli, and demethylated in regenerants. These genes were more frequent in chromosomal regions with higher gene density. Comparisons with an expression microarray dataset showed that genes methylated at both promoters and gene bodies had lower expression than genes that were unmethylated or only promoter-methylated in all three tissues. Four types of abundant transposable elements showed their highest levels of 5mC in regenerated internodes. CONCLUSIONS DNA methylation varies in a highly gene- and chromosome-differential manner during in vitro differentiation and regeneration. 5mC in redifferentiated tissues was not reset to that in original explants during the study period. Hypermethylation of gene bodies in dedifferentiated cells did not interfere with transcription, and may serve a protective role against activation of abundant transposable elements.
Collapse
Affiliation(s)
- Kelly Vining
- Department of Forest Ecosystems and Society, 321 Richardson Hall, Corvallis, OR, USA
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR 97331, USA
| | - Kyle R Pomraning
- Molecular and Cellular Biology Program, Corvallis, OR 97331, USA
- Department of Biochemistry and Biophysics, Corvallis, OR 97331, USA
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR 97331, USA
| | | | - Cathleen Ma
- Department of Forest Ecosystems and Society, 321 Richardson Hall, Corvallis, OR, USA
| | - Matteo Pellegrini
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA
| | - Yanming Di
- Statistics Department, Oregon State University, Corvallis, Oregon, USA
| | - Todd C Mockler
- The Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
| | - Michael Freitag
- Molecular and Cellular Biology Program, Corvallis, OR 97331, USA
- Department of Biochemistry and Biophysics, Corvallis, OR 97331, USA
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR 97331, USA
| | - Steven H Strauss
- Department of Forest Ecosystems and Society, 321 Richardson Hall, Corvallis, OR, USA
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR 97331, USA
| |
Collapse
|
48
|
Wang X, Wu R, Lin X, Bai Y, Song C, Yu X, Xu C, Zhao N, Dong Y, Liu B. Tissue culture-induced genetic and epigenetic alterations in rice pure-lines, F1 hybrids and polyploids. BMC PLANT BIOLOGY 2013; 13:77. [PMID: 23642214 PMCID: PMC3648424 DOI: 10.1186/1471-2229-13-77] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Accepted: 04/26/2013] [Indexed: 05/09/2023]
Abstract
BACKGROUND Genetic and epigenetic alterations can be invoked by plant tissue culture, which may result in heritable changes in phenotypes, a phenomenon collectively termed somaclonal variation. Although extensive studies have been conducted on the molecular nature and spectrum of tissue culture-induced genomic alterations, the issue of whether and to what extent distinct plant genotypes, e.g., pure-lines, hybrids and polyploids, may respond differentially to the tissue culture condition remains poorly understood. RESULTS We investigated tissue culture-induced genetic and epigenetic alterations in a set of rice genotypes including two pure-lines (different subspecies), a pair of reciprocal F1 hybrids parented by the two pure-lines, and a pair of reciprocal tetraploids resulted from the hybrids. Using two molecular markers, amplified fragment length polymorphism (AFLP) and methylation-sensitive amplified polymorphism (MSAP), both genetic and DNA methylation alterations were detected in calli and regenerants from all six genotypes, but genetic alteration is more prominent than epigenetic alteration. While significant genotypic difference was observed in frequencies of both types of alterations, only genetic alteration showed distinctive features among the three types of genomes, with one hybrid (N/9) being exceptionally labile. Surprisingly, difference in genetic alteration frequencies between the pair of reciprocal F1 hybrids is much greater than that between the two pure-line subspecies. Difference also exists in the pair of reciprocal tetraploids, but is to a less extent than that between the hybrids. The steady-state transcript abundance of genes involved in DNA repair and DNA methylation was significantly altered in both calli and regenerants, and some of which were correlated with the genetic and/or epigenetic alterations. CONCLUSIONS Our results, based on molecular marker analysis of ca. 1,000 genomic loci, document that genetic alteration is the major cause of somaclonal variation in rice, which is concomitant with epigenetic alterations. Perturbed expression by tissue culture of a set of 41 genes encoding for enzymes involved in DNA repair and DNA methylation is associated with both genetic and epigenetic alterations. There exist fundamental differences among distinct genotypes, pure-lines, hybrids and tetraploids, in propensities of generating both genetic and epigenetic alterations under the tissue culture condition. Parent-of-origin has a conspicuous effect on the alteration frequencies.
Collapse
Affiliation(s)
- Xiaoran Wang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Rui Wu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
- Present address: Carnegie Institution for Science, Department of Plant Biology, Stanford University, Stanford, CA, 94305, USA
| | - Xiuyun Lin
- Jilin Academy of Agricultural Sciences, Changchun, 130033, China
| | - Yan Bai
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Congdi Song
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Xiaoming Yu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
- School of Bioengineering, Jilin College of Agricultural Science & Technology, Jilin, 132301, China
| | - Chunming Xu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| | - Na Zhao
- Faculty of Agronomy, Jilin Agricultural University, Changchun, 13118, China
| | - Yuzhu Dong
- School of Life Science, Changchun Normal University, Changchun, 130032, China
| | - Bao Liu
- Key Laboratory of Molecular Epigenetics of the Ministry of Education (MOE), Northeast Normal University, Changchun, 130024, China
| |
Collapse
|
49
|
ROS-mediated vascular homeostatic control of root-to-shoot soil Na delivery in Arabidopsis. EMBO J 2012; 31:4359-70. [PMID: 23064146 PMCID: PMC3501220 DOI: 10.1038/emboj.2012.273] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 09/12/2012] [Indexed: 01/12/2023] Open
Abstract
Sodium (Na) is ubiquitous in soils, and is transported to plant shoots via transpiration through xylem elements in the vascular tissue. However, excess Na is damaging. Accordingly, control of xylem-sap Na concentration is important for maintenance of shoot Na homeostasis, especially under Na stress conditions. Here we report that shoot Na homeostasis of Arabidopsis thaliana plants grown in saline soils is conferred by reactive oxygen species (ROS) regulation of xylem-sap Na concentrations. We show that lack of A. thaliana respiratory burst oxidase protein F (AtrbohF; an NADPH oxidase catalysing ROS production) causes hypersensitivity of shoots to soil salinity. Lack of AtrbohF-dependent salinity-induced vascular ROS accumulation leads to increased Na concentrations in root vasculature cells and in xylem sap, thus causing delivery of damaging amounts of Na to the shoot. We also show that the excess shoot Na delivery caused by lack of AtrbohF is dependent upon transpiration. We conclude that AtrbohF increases ROS levels in wild-type root vasculature in response to raised soil salinity, thereby limiting Na concentrations in xylem sap, and in turn protecting shoot cells from transpiration-dependent delivery of excess Na.
Collapse
|
50
|
Scientific opinion addressing the safety assessment of plants developed using Zinc Finger Nuclease 3 and other Site‐Directed Nucleases with similar function. EFSA J 2012. [DOI: 10.2903/j.efsa.2012.2943] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
|