scholarly journals Copper Ions Induce DNA Sequence Variation in Zygotic Embryo Culture-Derived Barley Regenerants

2021 ◽  
Vol 11 ◽  
Author(s):  
Renata Orłowska ◽  
Janusz Zimny ◽  
Piotr T. Bednarek

In vitro tissue culture could be exploited to study cellular mechanisms that induce sequence variation. Altering the metal ion composition of tissue culture medium affects biochemical pathways involved in tissue culture-induced variation. Copper ions are involved in the mitochondrial respiratory chain and Yang cycle. Copper ions may participate in oxidative mutations, which may contribute to DNA sequence variation. Silver ions compete with copper ions to bind to the complex IV subunit of the respiratory chain, thus affecting the Yang cycle and DNA methylation. The mechanisms underlying somaclonal variation are unknown. In this study, we evaluated embryo-derived barley regenerants obtained from a single double-haploid plant via embryo culture under varying copper and silver ion concentrations and different durations of in vitro culture. Morphological variation among regenerants and the donor plant was not evaluated. Methylation-sensitive Amplified Fragment Length Polymorphism analysis of DNA samples showed DNA methylation pattern variation in CG and CHG (H = A, C, or T) sequence contexts. Furthermore, modification of in vitro culture conditions explained DNA sequence variation, demethylation, and de novo methylation in the CHG context, as indicated by analysis of variance. Linear regression indicated that DNA sequence variation was related to de novo DNA methylation in the CHG context. Mediation analysis showed the role of copper ions as a mediator of sequence variation in the CHG context. No other contexts showed a significant sequence variation in mediation analysis. Silver ions did not act as a mediator between any methylation contexts and sequence variation. Thus, incorporating copper ions in the induction medium should be treated with caution.

2020 ◽  
Vol 21 (16) ◽  
pp. 5770
Author(s):  
Piotr T. Bednarek ◽  
Jacek Zebrowski ◽  
Renata Orłowska

Tissue culture is an essential tool for the regeneration of uniform plant material. However, tissue culture conditions can be a source of abiotic stress for plants, leading to changes in the DNA sequence and methylation patterns. Despite the growing evidence on biochemical processes affected by abiotic stresses, how these altered biochemical processes affect DNA sequence and methylation patterns remains largely unknown. In this study, the methylation-sensitive Amplified Fragment Length Polymorphism (metAFLP) approach was used to investigate de novo methylation, demethylation, and sequence variation in barley regenerants derived by anther culture. Additionally, we used Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy to identify the spectral features of regenerants, which were then analyzed by mediation analysis. The infrared spectrum ranges (710–690 and 1010–940 cm−1) identified as significant in the mediation analysis were most likely related to β-glucans, cellulose, and S-adenosyl-L-methionine (SAM). Additionally, the identified compounds participated as predictors in moderated mediation analysis, explaining the role of demethylation of CHG sites (CHG_DMV) in in vitro tissue culture-induced sequence variation, depending on the duration of tissue culture. The data demonstrate that ATR-FTIR spectroscopy is a useful tool for studying the biochemical compounds that may affect DNA methylation patterns and sequence variation, if combined with quantitative characteristics determined using metAFLP molecular markers and mediation analysis. The role of β-glucans, cellulose, and SAM in DNA methylation, and in cell wall, mitochondria, and signaling, are discussed to highlight the putative cellular mechanisms involved in sequence variation.


2021 ◽  
Vol 22 (13) ◽  
pp. 6783
Author(s):  
Renata Orłowska ◽  
Katarzyna A. Pachota ◽  
Wioletta M. Dynkowska ◽  
Agnieszka Niedziela ◽  
Piotr T. Bednarek

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.


2020 ◽  
Author(s):  
Piotr Tomasz Bednarek ◽  
Renata Orłowska

Abstract BackgroundPlant regeneration via anther cultures is a world-wide approach as it allows for the regeneration of uniform and homozygous double haploids. Recent studies have shown that in vitro cultures are the origin of the so-called tissue culture-induced variation (TCIV) that may lead to off-type regenerants. Moreover, the regeneration of green plants may be limited by the presence of albinos. It was demonstrated that the presence of Cu2+ and Ag+ ions in the regeneration medium might increase the number of green plants.ResultsDArTseqMet markers were evaluated based on regenerants and donor plants derived via in vitro anther cultures of barley. The regenerants were obtained under varying Cu2+ and Ag+ ion concentration in the regeneration medium during distinct time conditions of the tissue cultures. The DArTseqMet markers were quantified using a semi-quantitative MSAP approach delivering data on CG and CHG sequence contexts de novo methylation and demethylation. Under each tissue culture conditions, the number of regenerated green plants per 100 anthers was evaluated. Conditional moderation analysis was applied to test for the role of Cu2+ and Ag+ ions in the medium. Moreover, the importance of the time of in vitro anther cultures were analyzed.ConclusionsOur data demonstrate that DNA de novo methylation and demethylation affecting CG and CXG DNA sequence contexts is moderated by the presence of Cu2+ and Ag+ ions in the medium conditional on the time of in vitro tissue cultures. The level of de novo methylation and demethylation and the difference between the two is essential for the understanding of moderation. Moreover, Cu2+ and Ag+ play in concert moderating DNA methylation changes. For the in vitro tissue culture purposes, the lower the delta value equal to de novo methylation less demethylation and the higher the value of the (Cu+Ag) predictor conditional on time, the higher the number of green plants should be evaluated. Moreover, evaluation of GPs is even more probable under positive delta and higher (Cu+Ag) values. Our data are congruent with the putative function of these ions in the ethylene and DNA methylation pathways.


2019 ◽  
Vol 11 (9) ◽  
pp. 2517-2530 ◽  
Author(s):  
Boris Yagound ◽  
Nicholas M A Smith ◽  
Gabriele Buchmann ◽  
Benjamin P Oldroyd ◽  
Emily J Remnant

Abstract DNA methylation is an important epigenetic modification that mediates diverse processes such as cellular differentiation, phenotypic plasticity, and genomic imprinting. Mounting evidence suggests that local DNA sequence variation can be associated with particular DNA methylation states, indicating that the interplay between genetic and epigenetic factors may contribute synergistically to the phenotypic complexity of organisms. Social insects such as ants, bees, and wasps have extensive phenotypic plasticity manifested in their different castes, and this plasticity has been associated with variation in DNA methylation. Yet, the influence of genetic variation on DNA methylation state remains mostly unknown. Here we examine the importance of sequence-specific methylation at the genome-wide level, using whole-genome bisulfite sequencing of the semen of individual honey bee males. We find that individual males harbor unique DNA methylation patterns in their semen, and that genes that are more variable at the epigenetic level are also more likely to be variable at the genetic level. DNA sequence variation can affect DNA methylation by modifying CG sites directly, but can also be associated with local variation in cis that is not CG-site specific. We show that covariation in sequence polymorphism and DNA methylation state contributes to the individual-specificity of epigenetic marks in social insects, which likely promotes their retention across generations, and their capacity to influence evolutionary adaptation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bertanne Visser ◽  
Hans T. Alborn ◽  
Suzon Rondeaux ◽  
Manon Haillot ◽  
Thierry Hance ◽  
...  

AbstractNumerous cases of evolutionary trait loss and regain have been reported over the years. Here, we argue that such reverse evolution can also become apparent when trait expression is plastic in response to the environment. We tested this idea for the loss and regain of fat synthesis in parasitic wasps. We first show experimentally that the wasp Leptopilina heterotoma switches lipogenesis on in a fat-poor environment, and completely off in a fat-rich environment. Plasticity suggests that this species did not regain fat synthesis, but that it can be switched off in some environmental settings. We then compared DNA sequence variation and protein domains of several more distantly related parasitoid species thought to have lost lipogenesis, and found no evidence for non-functionality of key lipogenesis genes. This suggests that other parasitoids may also show plasticity of fat synthesis. Last, we used individual-based simulations to show that a switch for plastic expression can remain functional in the genome for thousands of generations, even if it is only used sporadically. The evolution of plasticity could thus also explain other examples of apparent reverse evolution.


2006 ◽  
Vol 34 (18) ◽  
pp. e121-e121 ◽  
Author(s):  
C. H. Cannon ◽  
C. S. Kua ◽  
E. K. Lobenhofer ◽  
P. Hurban

Recent advances in nucleic acid technology have facilitated the detection and detailed structural analysis of a wide variety of genes in higher organisms, including those in man. This in turn has opened the way to an examination of the evolution of structural genes and their surrounding and intervening sequences. In a study of the evolution of haemoglobin genes and neighbouring sequences in man and the primates, we have investigated gene arrangement and DNA sequence divergence both within and between species ranging from Old World monkeys to man. This analysis is beginning to reveal the evolutionary constraints that have acted on this region of the genome during primate evolution. Furthermore, DNA sequence variation, both within and between species, provides, in principle, a novel and powerful method for determining inter-specific phylogenetic distances and also for analysing the structure of present-day human populations. Application of this new branch of molecular biology to other areas of the human genome should prove important in unravelling the history of genetic changes that have occurred during the evolution of man.


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