scholarly journals Changes in DNA Methylation in Arabidopsis thaliana Plants Exposed Over Multiple Generations to Gamma Radiation

2021 ◽  
Vol 12 ◽  
Author(s):  
Pol Laanen ◽  
Eline Saenen ◽  
Mohamed Mysara ◽  
Jorden Van de Walle ◽  
May Van Hees ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Arabidopsis Thaliana ◽  
Transposable Elements ◽  
Gamma Radiation ◽  
Stress Responses ◽  
Whole Genome ◽  
Multiple Generations ◽  
Three Generations ◽  
Two Generations

Previous studies have found indications that exposure to ionising radiation (IR) results in DNA methylation changes in plants. However, this phenomenon is yet to be studied across multiple generations. Furthermore, the exact role of these changes in the IR-induced plant response is still far from understood. Here, we study the effect of gamma radiation on DNA methylation and its effect across generations in young Arabidopsis plants. A multigenerational set-up was used in which three generations (Parent, generation 1, and generation 2) of 7-day old Arabidopsis thaliana plants were exposed to either of the different radiation treatments (30, 60, 110, or 430 mGy/h) or to natural background radiation (control condition) for 14 days. The parental generation consisted of previously non-exposed plants, whereas generation 1 and generation 2 plants had already received a similar irradiation in the previous one or two generations, respectively. Directly after exposure the entire methylomes were analysed with UPLC-MS/MS to measure whole genome methylation levels. Whole genome bisulfite sequencing was used to identify differentially methylated regions (DMRs), including their methylation context in the three generations and this for three different radiation conditions (control, 30 mGy/h, and 110 mGy/h). Both intra- and intergenerational comparisons of the genes and transposable elements associated with the DMRs were made. Taking the methylation context into account, the highest number of changes were found for cytosines followed directly by guanine (CG methylation), whereas only limited changes in CHG methylation occurred and no changes in CHH methylation were observed. A clear increase in IR-induced DMRs was seen over the three generations that were exposed to the lowest dose rate, where generation 2 had a markedly higher number of DMRs than the previous two generations (Parent and generation 1). Counterintuitively, we did not see significant differences in the plants exposed to the highest dose rate. A large number of DMRs associated with transposable elements were found, the majority of them being hypermethylated, likely leading to more genetic stability. Next to that, a significant number of DMRs were associated with genes (either in their promoter-associated region or gene body). A functional analysis of these genes showed an enrichment for genes related to development as well as various stress responses, including DNA repair, RNA splicing, and (a)biotic stress responses. These observations indicate a role of DNA methylation in the regulation of these genes in response to IR exposure and shows a possible role for epigenetics in plant adaptation to IR over multiple generations.

scholarly journals Whole-Genome DNA Methylation Analysis in Hydrogen Peroxide Overproducing Transgenic Tobacco Resistant to Biotic and Abiotic Stresses

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 178
Author(s):  
Ana L. Villagómez-Aranda ◽  
Luis F. García-Ortega ◽  
Irineo Torres-Pacheco ◽  
Ramón G. Guevara-González
Keyword(s):  
Hydrogen Peroxide ◽  
Dna Methylation ◽  
Transgenic Tobacco ◽  
Stress Responses ◽  
Abiotic Stresses ◽  
Methylation Status ◽  
Physiological Adaptation ◽  
Whole Genome ◽  
Sequencing Analysis ◽  
Biotic And Abiotic Stresses

Epigenetic regulation is a key component of stress responses, acclimatization and adaptation processes in plants. DNA methylation is a stable mark plausible for the inheritance of epigenetic traits, such that it is a potential scheme for plant breeding. However, the effect of modulators of stress responses, as hydrogen peroxide (H2O2), in the methylome status has not been elucidated. A transgenic tobacco model to the CchGLP gene displayed high H2O2 endogen levels correlated with biotic and abiotic stresses resistance. The present study aimed to determine the DNA methylation status changes in the transgenic model to obtain more information about the molecular mechanism involved in resistance phenotypes. The Whole-genome bisulfite sequencing analysis revealed a minimal impact of overall levels and distribution of methylation. A total of 9432 differential methylated sites were identified in distinct genome regions, most of them in CHG context, with a trend to hypomethylation. Of these, 1117 sites corresponded to genes, from which 83 were also differentially expressed in the plants. Several genes were associated with respiration, energy, and calcium signaling. The data obtained highlighted the relevance of the H2O2 in the homeostasis of the system in stress conditions, affecting at methylation level and suggesting an association of the H2O2 in the physiological adaptation to stress functional linkages may be regulated in part by DNA methylation.

The Development of an Entrepreneurial Legacy: Exploring the Role of Anticipated Futures in Transgenerational Entrepreneurship

2018 ◽  
Vol 31 (3) ◽  
pp. 352-378 ◽  
Author(s):  
Francesco Barbera ◽  
Isabell Stamm ◽  
Rocki-Lee DeWitt
Keyword(s):  
Multiple Generations ◽  
Dynamic Character ◽  
The Past ◽  
Three Generations ◽  
Family Storytelling ◽  
Business Family ◽  
Analysis Of Narratives ◽  
Forward Looking

Entrepreneurial legacies play an important role in transgenerational entrepreneurship, yet little is known about their nature and development. Through a multilayered analysis of narratives drawn from three generations of a single business family, we document that entrepreneurial legacies feature both stable and fluid elements, and that forward-looking components in family storytelling—which we refer to as “anticipated futures”—affect this dynamic character. We further show how such narratives can prompt, sustain, and disrupt entrepreneurship across multiple generations. Our findings offer insights that refine our understanding of entrepreneurial legacies beyond mere projections of the past through secondhand imprinting.

scholarly journals Evolutionary and functional genomics of DNA methylation in maize domestication and improvement

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Gen Xu ◽  
Jing Lyu ◽  
Qing Li ◽  
Han Liu ◽  
Dafang Wang ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Direct Selection ◽  
Whole Genome ◽  
Evolutionary Forces ◽  
Weak Evidence ◽  
Modern Maize ◽  
Genome Bisulfite Sequencing ◽  
Maize Domestication ◽  
Chromatin Feature

Abstract DNA methylation is a ubiquitous chromatin feature, present in 25% of cytosines in the maize genome, but variation and evolution of the methylation landscape during maize domestication remain largely unknown. Here, we leverage whole-genome sequencing (WGS) and whole-genome bisulfite sequencing (WGBS) data on populations of modern maize, landrace, and teosinte (Zea mays ssp. parviglumis) to estimate epimutation rates and selection coefficients. We find weak evidence for direct selection on DNA methylation in any context, but thousands of differentially methylated regions (DMRs) are identified population-wide that are correlated with recent selection. For two trait-associated DMRs, vgt1-DMR and tb1-DMR, HiChIP data indicate that the interactive loops between DMRs and respective downstream genes are present in B73, a modern maize line, but absent in teosinte. Our results enable a better understanding of the evolutionary forces acting on patterns of DNA methylation and suggest a role of methylation variation in adaptive evolution.

scholarly journals ARPEGGIO: Automated Reproducible Polyploid EpiGenetic GuIdance workflOw

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Stefan Milosavljevic ◽  
Tony Kuo ◽  
Samuele Decarli ◽  
Lucas Mohn ◽  
Jun Sese ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Molecular Mechanisms ◽  
Sequence Similarity ◽  
Ground Truth ◽  
Whole Genome ◽  
Initial Dataset ◽  
Quality Checks ◽  
Living Organisms ◽  
Set Up

Abstract Background Whole genome duplication (WGD) events are common in the evolutionary history of many living organisms. For decades, researchers have been trying to understand the genetic and epigenetic impact of WGD and its underlying molecular mechanisms. Particular attention was given to allopolyploid study systems, species resulting from an hybridization event accompanied by WGD. Investigating the mechanisms behind the survival of a newly formed allopolyploid highlighted the key role of DNA methylation. With the improvement of high-throughput methods, such as whole genome bisulfite sequencing (WGBS), an opportunity opened to further understand the role of DNA methylation at a larger scale and higher resolution. However, only a few studies have applied WGBS to allopolyploids, which might be due to lack of genomic resources combined with a burdensome data analysis process. To overcome these problems, we developed the Automated Reproducible Polyploid EpiGenetic GuIdance workflOw (ARPEGGIO): the first workflow for the analysis of epigenetic data in polyploids. This workflow analyzes WGBS data from allopolyploid species via the genome assemblies of the allopolyploid’s parent species. ARPEGGIO utilizes an updated read classification algorithm (EAGLE-RC), to tackle the challenge of sequence similarity amongst parental genomes. ARPEGGIO offers automation, but more importantly, a complete set of analyses including spot checks starting from raw WGBS data: quality checks, trimming, alignment, methylation extraction, statistical analyses and downstream analyses. A full run of ARPEGGIO outputs a list of genes showing differential methylation. ARPEGGIO was made simple to set up, run and interpret, and its implementation ensures reproducibility by including both package management and containerization. Results We evaluated ARPEGGIO in two ways. First, we tested EAGLE-RC’s performance with publicly available datasets given a ground truth, and we show that EAGLE-RC decreases the error rate by 3 to 4 times compared to standard approaches. Second, using the same initial dataset, we show agreement between ARPEGGIO’s output and published results. Compared to other similar workflows, ARPEGGIO is the only one supporting polyploid data. Conclusions The goal of ARPEGGIO is to promote, support and improve polyploid research with a reproducible and automated set of analyses in a convenient implementation. ARPEGGIO is available at https://github.com/supermaxiste/ARPEGGIO.

scholarly journals BoostMe accurately predicts DNA methylation values in whole-genome bisulfite sequencing of multiple human tissues

2017 ◽  
Author(s):  
Luli S. Zou ◽  
Michael R. Erdos ◽  
D. Leland Taylor ◽  
Peter S. Chines ◽  
Arushi Varshney ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Bisulfite Sequencing ◽  
Gradient Boosting ◽  
Whole Genome ◽  
Human Tissues ◽  
Whole Genome Bisulfite Sequencing ◽  
Genome Bisulfite Sequencing ◽  
Boosting Algorithm ◽  
Multiple Samples

AbstractBisulfite sequencing is widely employed to study the role of DNA methylation in disease; however, the data suffer from biases due to coverage depth variability. Here we describe BoostMe, a method for imputing low quality DNA methylation estimates within whole-genome bisulfite sequencing (WGBS) data. BoostMe uses a gradient boosting algorithm, XGBoost, and leverages information from multiple samples for prediction. We find that BoostMe outperforms existing algorithms in speed and accuracy when applied to WGBS of human tissues. We also show that imputation improves concordance between WGBS and the MethylationEPIC array at low WGBS depth, suggesting improved WGBS accuracy after imputation.

P–529 Whole-genome methylation analysis of testicular germ cells from cryptozoospermic men points to recurrent and functionally relevant DNA methylation changes

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
S D Persio ◽  
E Leitão ◽  
M Wöste ◽  
T Tekath ◽  
J F Cremers ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Germ Cell ◽  
Germ Cells ◽  
Small Sample ◽  
Global Dna Methylation ◽  
Obstructive Azoospermia ◽  
Whole Genome ◽  
Ploidy Analysis ◽  
Normal Spermatogenesis

Abstract Study question Do DNA methylation changes occur in testicular germ cells (TGCs) from patients with impaired spermatogenesis? Summary answer TGCs from men with cryptozoospermia exhibit altered DNA methylation levels at several genomic regions, many of which are associated with genes involved in spermatogenesis. What is known already In the last 15 years, several studies have described DNA methylation changes in sperm of infertile men. More recently, using whole genome bisulfite sequencing (WGBS) we were able to refute these findings by demonstrating that somatic DNA contamination and genetic variation confound methylation studies in swim-up purified sperm of severely oligozoospermic men. However, it remains unknown whether altered DNA methylation plays a role during the development of the germ cells in the testes of these patients. Study design, size, duration For identifying DNA methylation differences associated with impaired spermatogenesis, we compared the TGC methylomes of men with cryptozoospermia (CZ) and men with obstructive azoospermia (n = 4 each), who had normal spermatogenesis and served as controls (CTR). Study participants were selected among an age-matched cohort of 24 CTR and 10 CZ. The selection was based on similar composition of the TGC suspension evaluated by ploidy analysis and absence of somatic DNA. Participants/materials, setting, methods TGCs were isolated from biopsies after short-term cell culture. Presence of somatic DNA was evaluated by analyzing the DNA methylation levels of H19, MEST, DDX4 and XIST. WGBS was performed at ∼14× coverage. Bioinformatic tools were used to compare global DNA methylation levels, identify differentially methylated regions (DMRs) and functionally annotate the DMRs. Single-cell RNA sequencing (scRNA-seq) was used to associate the DNA methylation changes to gene expression. Main results and the role of chance We could not identify any difference in the global DNA methylation level or at imprinted regions between CZ and CTR samples. However, using stringent filters to identify group-specific methylation differences, we detected 271 DMRs, 238 of which were hypermethylated in CZ (binominal test, p < 2.2 × 10–16). The DMRs are associated with 132 genes, 61 of which are known to be differentially expressed at various stages of spermatogenesis according to scRNA-seq studies. Almost all of the DMRs associated with the 61 genes are hypermethylated in CZ (63/67, p = 1.107 × 10–14). As assessed by scRNA-seq, 13 DMR-associated genes, which were mainly expressed during meiosis and spermiogenesis, show a significantly different pattern of expression in CZ patients. In four of these genes, the promoter was hypermethylated in CZ men, which correlates with a lower expression level in these patients. In the other nine genes, most of which downregulated in CZ, germ cell-specific enhancers may be affected. Limitations, reasons for caution The small sample size constitutes a limitation of this study. Furthermore, even though the cellular composition of samples was similar by ploidy analysis, we cannot rule out that the observed DNA methylation changes might be due to differences in the relative proportion of different germ cell types. Wider implications of the findings: Impaired spermatogenesis is associated with DNA methylation changes in testicular germ cells at functionally relevant regions of the genome, which points to an important role of DNA methylation in normal spermatogenesis. The DNA methylation changes may contribute to premature abortion of spermatogenesis and therefore not appear in mature sperm. Trial registration number N/A

scholarly journals Role of DNA methylation in hybrid vigor in Arabidopsis thaliana

2016 ◽  
Vol 113 (43) ◽  
pp. E6704-E6711 ◽  
Author(s):  
Takahiro Kawanabe ◽  
Sonoko Ishikura ◽  
Naomi Miyaji ◽  
Taku Sasaki ◽  
Li Min Wu ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Arabidopsis Thaliana ◽  
Production Systems ◽  
Hybrid Vigor ◽  
Superior Performance ◽  
Partial Reduction ◽  
Hybrid Plants ◽  
Rna Polymerase Iv ◽  
Mutant Genes

Hybrid vigor or heterosis refers to the superior performance of F1 hybrid plants over their parents. Heterosis is particularly important in the production systems of major crops. Recent studies have suggested that epigenetic regulation such as DNA methylation is involved in heterosis, but the molecular mechanism of heterosis is still unclear. To address the epigenetic contribution to heterosis in Arabidopsis thaliana, we used mutant genes that have roles in DNA methylation. Hybrids between C24 and Columbia-0 (Col) without RNA polymerase IV (Pol IV) or methyltransferase I (MET1) function did not reduce the level of biomass heterosis (as evaluated by rosette diameter). Hybrids with a mutation in decrease in dna methylation 1 (ddm1) showed a decreased heterosis level. Vegetative heterosis in the ddm1 mutant hybrid was reduced but not eliminated; a complete reduction could result if there was a change in methylation at all loci critical for generating the level of heterosis, whereas if only a proportion of the loci have methylation changes there may only be a partial reduction in heterosis.

scholarly journals The plant mobile domain proteins MAIN and MAIL1 interact with the phosphatase PP7L to regulate gene expression and silence transposable elements in Arabidopsis thaliana

2019 ◽  
Author(s):  
Melody Nicolau ◽  
Nathalie Picault ◽  
Julie Descombin ◽  
Yasaman Jami-Alahmadi ◽  
Suhua Feng ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Arabidopsis Thaliana ◽  
Transposable Elements ◽  
Genome Stability ◽  
Phylogenetic Analyses ◽  
Dna Repeats ◽  
Functional Protein ◽  
Developmental Processes ◽  
Phosphoprotein Phosphatase

ABSTRACTTransposable elements (TEs) are DNA repeats that must remain silenced to ensure cell integrity. Several epigenetic pathways including DNA methylation and histone modifications are involved in the silencing of TEs, and in the regulation of gene expression. In Arabidopsis thaliana, the TE-derived plant mobile domain (PMD) proteins have been involved in TE silencing, genome stability, and control of developmental processes. Using a forward genetic screen, we found that the PMD protein MAINTENANCE OF MERISTEMS (MAIN) acts synergistically and redundantly with DNA methylation to silence TEs. We found that MAIN and its close homolog MAIN-LIKE 1 (MAIL1) interact together, as well as with the phosphoprotein phosphatase (PPP) PP7-like (PP7L). Remarkably, main, mail1, pp7l single and mail1 pp7l double mutants display similar developmental phenotypes, and share common subsets of upregulated TEs and misregulated genes. Finally, phylogenetic analyses of PMD and PP7-type PPP domains among the Eudicot lineage suggest neo-association processes between the two protein domains to potentially generate new protein function. We propose that, through this interaction, the PMD and PPP domains may constitute a functional protein module required for the proper expression of a common set of genes, and for silencing of TEs.AUTHOR SUMMARYThe plant mobile domain (PMD) is a protein domain of unknown function that is widely spread in the angiosperm plants. Although most PMDs are associated with repeated DNA sequences called transposable elements (TEs), plants have domesticated the PMD to produce genic versions that play important roles within the cell. In Arabidopsis thaliana, MAINTENANCE OF MERISTEMS (MAIN) and MAIN-LIKE 1 (MAIL1) are genic PMDs that are involved in genome stability, developmental processes, and silencing of TEs. The mechanisms involving MAIN and MAIL1 in these cellular processes remain elusive. Here, we show that MAIN, MAIL1 and the phosphoprotein phosphatase (PPP) named PP7-like (PP7L) interact to form a protein complex that is required for the proper expression of genes, and the silencing of TEs. Phylogenetic analyses revealed that PMD and PP7-type PPP domains are evolutionary connected, and several plant species express proteins carrying both PMD and PPP domains. We propose that interaction of PMD and PPP domains would create a functional protein module involved in mechanisms regulating gene expression and repressing TEs.

scholarly journals Pathway conversion enables a double-lock mechanism to maintain DNA methylation and genome stability

2021 ◽  
Vol 118 (35) ◽  
pp. e2107320118
Author(s):  
Li He ◽  
Cheng Zhao ◽  
Qingzhu Zhang ◽  
Gaurav Zinta ◽  
Dong Wang ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Arabidopsis Thaliana ◽  
Transposable Elements ◽  
Genome Stability ◽  
First Generation ◽  
Genomic Stability ◽  
Genome Integrity ◽  
Chromatin Remodeler ◽  
Genomic Regions

The CMT2 and RNA-directed DNA methylation (RdDM) pathways have been proposed to separately maintain CHH methylation in specific regions of the Arabidopsis thaliana genome. Here, we show that dysfunction of the chromatin remodeler DDM1 causes hundreds of genomic regions to switch from CMT2 dependency to RdDM dependency in DNA methylation. These converted loci are enriched at the edge regions of long transposable elements (TEs). Furthermore, we found that dysfunction in both DDM1 and RdDM causes strong reactivation of TEs and a burst of TE transposition in the first generation of mutant plants, indicating that the DDM1 and RdDM pathways together are critical to maintaining TE repression and protecting genomic stability. Our findings reveal the existence of a pathway conversion–based backup mechanism to guarantee the maintenance of DNA methylation and genome integrity.

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