scholarly journals Ocean acidification induces subtle shifts in gene expression and DNA methylation in mantle tissue of the Eastern oyster (Crassostrea virginica)

2020 ◽  
Author(s):  
Alan M. Downey-Wall ◽  
Louise P. Cameron ◽  
Brett M. Ford ◽  
Elise M. McNally ◽  
Yaamini R. Venkataraman ◽  
...  

AbstractEarly evidence suggests that DNA methylation can mediate phenotypic responses of marine calcifying species to ocean acidification (OA). Few studies, however, have explicitly studied DNA methylation in calcifying tissues through time. Here, we examined the phenotypic and molecular responses in the extrapallial fluid and mantle (fluid and tissue at the calcification site) in the Eastern oyster (Crassostrea virginica) exposed to experimental OA over 80 days. Oysters were reared under three experimental pCO2 treatments (‘control’, 580 μatm; ‘moderate OA’, 1000 uatm; ‘high OA’, 2800 μatm) and sampled at 6 time points (24 hours - 80 days). We found that high OA initially induced changes in the pH of the extrapallial fluid (pHEPF) relative to the external seawater, but the magnitude of this difference was highest at 9 days and diminished over time. Calcification rates were significantly lower in the high OA treatment compared to the other treatments. To explore how oysters regulate their extrapallial fluid, gene expression and DNA methylation were examined in the mantle-edge tissue of oysters from day 9 and 80 in the control and high OA treatments. Mantle tissue mounted a significant global molecular response (both in the transcriptome and methylome) to OA that shifted through time. Although we did not find individual genes that were significantly differentially expressed to OA, the pHEPF was correlated with the eigengene expression of several co-expressed gene clusters. A small number of OA-induced differentially methylated loci were discovered, which corresponded with a weak association between OA-induced changes in genome-wide gene body DNA methylation and gene expression. Gene body methylation, however, was not significantly correlated with the eigengene expression of pHEPF correlated gene clusters. These results suggest that in C. virginica, OA induces a subtle response in a large number of genes, but also indicates that plasticity at the molecular level may be limited. Our study highlights the need to re-assess the plasticity of tissue-specific molecular responses in marine calcifiers, as well as the role of DNA methylation and gene expression in mediating physiological and biomineralization responses to OA.

2020 ◽  
Vol 7 ◽  
Author(s):  
Alan M. Downey-Wall ◽  
Louise P. Cameron ◽  
Brett M. Ford ◽  
Elise M. McNally ◽  
Yaamini R. Venkataraman ◽  
...  

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Melanie Lindner ◽  
Irene Verhagen ◽  
Heidi M. Viitaniemi ◽  
Veronika N. Laine ◽  
Marcel E. Visser ◽  
...  

Abstract Background DNA methylation is likely a key mechanism regulating changes in gene transcription in traits that show temporal fluctuations in response to environmental conditions. To understand the transcriptional role of DNA methylation we need simultaneous within-individual assessment of methylation changes and gene expression changes over time. Within-individual repeated sampling of tissues, which are essential for trait expression is, however, unfeasible (e.g. specific brain regions, liver and ovary for reproductive timing). Here, we explore to what extend between-individual changes in DNA methylation in a tissue accessible for repeated sampling (red blood cells (RBCs)) reflect such patterns in a tissue unavailable for repeated sampling (liver) and how these DNA methylation patterns are associated with gene expression in such inaccessible tissues (hypothalamus, ovary and liver). For this, 18 great tit (Parus major) females were sacrificed at three time points (n = 6 per time point) throughout the pre-laying and egg-laying period and their blood, hypothalamus, ovary and liver were sampled. Results We simultaneously assessed DNA methylation changes (via reduced representation bisulfite sequencing) and changes in gene expression (via RNA-seq and qPCR) over time. In general, we found a positive correlation between changes in CpG site methylation in RBCs and liver across timepoints. For CpG sites in close proximity to the transcription start site, an increase in RBC methylation over time was associated with a decrease in the expression of the associated gene in the ovary. In contrast, no such association with gene expression was found for CpG site methylation within the gene body or the 10 kb up- and downstream regions adjacent to the gene body. Conclusion Temporal changes in DNA methylation are largely tissue-general, indicating that changes in RBC methylation can reflect changes in DNA methylation in other, often less accessible, tissues such as the liver in our case. However, associations between temporal changes in DNA methylation with changes in gene expression are mostly tissue- and genomic location-dependent. The observation that temporal changes in DNA methylation within RBCs can relate to changes in gene expression in less accessible tissues is important for a better understanding of how environmental conditions shape traits that temporally change in expression in wild populations.


2016 ◽  
Vol 113 (32) ◽  
pp. 9111-9116 ◽  
Author(s):  
Adam J. Bewick ◽  
Lexiang Ji ◽  
Chad E. Niederhuth ◽  
Eva-Maria Willing ◽  
Brigitte T. Hofmeister ◽  
...  

In plants, CG DNA methylation is prevalent in the transcribed regions of many constitutively expressed genes (gene body methylation; gbM), but the origin and function of gbM remain unknown. Here we report the discovery that Eutrema salsugineum has lost gbM from its genome, to our knowledge the first instance for an angiosperm. Of all known DNA methyltransferases, only CHROMOMETHYLASE 3 (CMT3) is missing from E. salsugineum. Identification of an additional angiosperm, Conringia planisiliqua, which independently lost CMT3 and gbM, supports that CMT3 is required for the establishment of gbM. Detailed analyses of gene expression, the histone variant H2A.Z, and various histone modifications in E. salsugineum and in Arabidopsis thaliana epigenetic recombinant inbred lines found no evidence in support of any role for gbM in regulating transcription or affecting the composition and modification of chromatin over evolutionary timescales.


2021 ◽  
Author(s):  
Carlos A. M. Cardoso-Junior ◽  
Boris Yagound ◽  
Isobel Ronai ◽  
Emily J. Remnant ◽  
Klaus Hartfelder ◽  
...  

AbstractIntragenic DNA methylation, also called gene body methylation, is an evolutionarily-conserved epigenetic mechanism in animals and plants. In social insects, gene body methylation is thought to contribute to behavioral plasticity, for example between foragers and nurse workers, by modulating gene expression. However, recent studies have suggested that the majority of DNA methylation is sequence-specific, and therefore cannot act as a flexible mediator between environmental cues and gene expression. To address this paradox, we examined whole-genome methylation patterns in the brains and ovaries of young honey bee workers that had been subjected to divergent social contexts: the presence or absence of the queen. Although these social contexts are known to bring about extreme changes in behavioral and reproductive traits through differential gene expression, we found no significant differences between the methylomes of workers from queenright and queenless colonies. In contrast, thousands of regions were differentially methylated between colonies, and these differences were not associated with differential gene expression in a subset of genes examined. Methylation patterns were highly similar between brain and ovary tissues and only differed in nine regions. These results strongly indicate that DNA methylation is not a driver of differential gene expression between tissues or behavioral morphs. Finally, despite the lack of difference in methylation patterns, queen presence affected the expression of all four DNA methyltransferase genes, suggesting that these enzymes have roles beyond DNA methylation. Therefore, the functional role of DNA methylation in social insect genomes remains an open question.


2016 ◽  
Vol 214 (1) ◽  
pp. S136-S137
Author(s):  
Hye J. Heo ◽  
Jessica Tozour ◽  
Fabien Delahaye ◽  
Yongmei Zhao ◽  
Lingguang Cui ◽  
...  

2017 ◽  
Vol 186 ◽  
pp. 196-204 ◽  
Author(s):  
Rodrigo Gonzalez-Romero ◽  
Victoria Suarez-Ulloa ◽  
Javier Rodriguez-Casariego ◽  
Daniel Garcia-Souto ◽  
Gabriel Diaz ◽  
...  

2015 ◽  
Vol 112 (44) ◽  
pp. 13729-13734 ◽  
Author(s):  
Haifeng Wang ◽  
Getu Beyene ◽  
Jixian Zhai ◽  
Suhua Feng ◽  
Noah Fahlgren ◽  
...  

DNA methylation is important for the regulation of gene expression and the silencing of transposons in plants. Here we present genome-wide methylation patterns at single-base pair resolution for cassava (Manihot esculenta, cultivar TME 7), a crop with a substantial impact in the agriculture of subtropical and tropical regions. On average, DNA methylation levels were higher in all three DNA sequence contexts (CG, CHG, and CHH, where H equals A, T, or C) than those of the most well-studied model plant Arabidopsis thaliana. As in other plants, DNA methylation was found both on transposons and in the transcribed regions (bodies) of many genes. Consistent with these patterns, at least one cassava gene copy of all of the known components of Arabidopsis DNA methylation pathways was identified. Methylation of LTR transposons (GYPSY and COPIA) was found to be unusually high compared with other types of transposons, suggesting that the control of the activity of these two types of transposons may be especially important. Analysis of duplicated gene pairs resulting from whole-genome duplication showed that gene body DNA methylation and gene expression levels have coevolved over short evolutionary time scales, reinforcing the positive relationship between gene body methylation and high levels of gene expression. Duplicated genes with the most divergent gene body methylation and expression patterns were found to have distinct biological functions and may have been under natural or human selection for cassava traits.


2020 ◽  
Author(s):  
Libo He ◽  
Denghui Zhu ◽  
Pengfei Chu ◽  
Yongming Li ◽  
Lanjie Liao ◽  
...  

Abstract Background: Grass carp is an important farmed fish in China that infected by many pathogens, especially grass carp reovirus (GCRV). Notably, grass carp showed age-dependent susceptibility to GCRV, while the mechanism remains unclear. Herein, we performed a genome-wide survey of differences in DNA methylation and gene expression between five months old grass carp (FMO, sensitive to GCRV) and three years old grass carp (TYO, resistant to GCRV) aim to uncover the mechanism.Results: Colorimetric quantification revealed global methylation level of TYO fish was higher than that of FMO fish. Whole-genome bisulfite sequencing (WGBS) of two groups revealed 6,214 differentially methylated regions (DMRs) and 4,052 differentially methylated genes (DMGs), with most of DMRs and DMGs showed hypermethylation patterns in TYO fish. Correlation analysis indicated that DNA hypomethylation in promoter negative correlated with gene expression, whereas positive correlation was found between gene-body DNA hypermethylation and gene expression. Enrichment analysis revealed that promoter hypo-DMGs in TYO fish were significant enriched in pathways involved in immune response while gene-body hyper-DMGs in TYO fish were significant enriched in terms related to RNA transcription, biosynthetic, and energy production. RNA-seq indicated these terms or pathways involved in immune response, biosynthetic, and energy production also significant enriched for the up-regulated genes in TYO fish. Conclusions: Collectively, these results revealed the genome-wide DNA methylation variations between grass carp with different ages. DNA methylation and gene expression variations in genes involved in immune response, biosynthetic, and energy production may contributed to the age-dependent susceptibility to GCRV in grass carp. Our results will provide important information for the disease-resistant breeding programs of grass carp and may also benefit to the research of age-dependent diseases in human.


2022 ◽  
Author(s):  
Nian Liu ◽  
Manish Pandey ◽  
Bei Wu ◽  
Li Huang ◽  
Huaiyong Luo ◽  
...  

Abstract The wild allotetraploid peanut Arachis monticola contains higher oil content than cultivated allotetraploid Arachis hypogaea. To investigate its molecular mechanism controlling oil accumulation, we performed comparative transcriptomics from developing seeds between three Arachis monticola and five Arachis hypogaea varieties. The analysis not only showed species-specific grouping based on transcriptional profiles but also detected two gene clusters with divergent expression patterns enriched in lipid metabolism. Further, the differential expression gene analysis also indicated expression alteration in wild peanut leading to enhanced activity of oil biogenesis and limiting the rate of lipid degradation. We also constructed a regulatory network of lipid metabolic DEGs with co-expressed transcription factors. In addition, bisulfite sequencing was conducted to characterize the variation of DNA methylation between wild allotetraploid (245, WH 10025) and cultivated allotetraploid (Z16, Zhh 7720) genotypes. Genome-wide DNA methylation was found antagonistically correlated with gene expression during seed development. The results indicated that CG and CHG contexts methylation may negatively regulate specific lipid metabolic genes and transcription factors to subtly affect the difference of oil accumulation. Our work provided the first glimpse on the regulatory mechanism of gene expression altering for oil accumulation in wild peanut and gene resources for future breeding applications.


2019 ◽  
Vol 37 (1) ◽  
pp. 31-43 ◽  
Author(s):  
Danelle K Seymour ◽  
Brandon S Gaut

Abstract A subset of genes in plant genomes are labeled with DNA methylation specifically at CG residues. These genes, known as gene-body methylated (gbM), have a number of associated characteristics. They tend to have longer sequences, to be enriched for intermediate expression levels, and to be associated with slower rates of molecular evolution. Most importantly, gbM genes tend to maintain their level of DNA methylation between species, suggesting that this trait is under evolutionary constraint. Given the degree of conservation in gbM, we still know surprisingly little about its function in plant genomes or whether gbM is itself a target of selection. To address these questions, we surveyed DNA methylation across eight grass (Poaceae) species that span a gradient of genome sizes. We first established that genome size correlates with genome-wide DNA methylation levels, but less so for genic levels. We then leveraged genomic data to identify a set of 2,982 putative orthologs among the eight species and examined shifts of methylation status for each ortholog in a phylogenetic context. A total of 55% of orthologs exhibited a shift in gbM, but these shifts occurred predominantly on terminal branches, indicating that shifts in gbM are rarely conveyed over time. Finally, we found that the degree of conservation of gbM across species is associated with increased gene length, reduced rates of molecular evolution, and increased gene expression level, but reduced gene expression variation across species. Overall, these observations suggest a basis for evolutionary pressure to maintain gbM status over evolutionary time.


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