Salt stress alters DNA methylation levels in alfalfa (Medicago spp)

Abstract

ABSTRACT. Modification of DNA methylation status is one of the mechanisms used by plants to adjust gene expression at both the transcriptional and posttranscriptional levels when plants are exposed to suboptimal conditions. Under abiotic stress, different cultivars often show heritable phenotypic variation accompanied by epigenetic polymorphisms at the DNA methylation level. This variation may provide the raw materials for plant breeding programs that aim to enhance abiotic stress tolerance, including salt tolerance. In this study, methylation-sensitive amplified polymorphism (MSAP) analysis was used to assess cytosine methylation levels in alfalfa (Medicago spp) roots exposed to increasing NaCl concentrations (0.0, 8.0, 12.0, and 20.0 dS/m). Eleven indigenous landraces were analyzed, in addition to a salt-tolerant cultivar that was used as a control. There was a slight increase in DNA methylation upon exposure to high levels of soil salinity. Phylogenetic analysis using MSAP showed epigenetic variation within and between the alfalfa landraces when exposed to saline conditions. Based on MSAP and enzyme-linked immunosorbent assay results, we found that salinity increased global DNA methylation status, particularly in plants exposed to the highest level of salinity (20 dS/m). Quantitative reverse transcription-polymerase chain reaction indicated that this might be mediated by the overexpression of methyltransferase homolog genes after exposure to saline conditions. DNA demethylation using 5-azacytidine reduced seedling lengths and dry and fresh weights, indicating a possible decrease in salinity tolerance. These results suggest that salinity affects DNA methylation flexibility.

Role of DNA methylation dynamics in desiccation and salinity stress responses in rice cultivars

“…This is interesting that desiccation stress response in Nagina 22 is mediated via hypomethylation in CHH context and salinity stress response in Pokkali is mediated via hypermethylation in CHH context. Previous studies have also demonstrated that hypomethylation associated with higher gene expression under drought/salinity stress response and hypermethylation associated with higher gene expression under salinity stress response (Boyko et al ., 2010; Wang et al ., 2014; Al-Lawati et al ., 2016). These results suggest that abiotic stress response(s) is dependent on cultivar specific manner.…”

“…However, methylation differences between drought-tolerant and susceptible cultivars under control conditions were mostly found in CG context in rice (Garg et al ., 2015). Likewise, methylation dynamics under salinity stress have also been investigated in susceptible and tolerant cultivars in different plants using various approaches, and methylation changes under the stress conditions were found to be genotype-specific (Wang et al ., 2014; Al-Lawati et al ., 2016; Lu et al ., 2017). Interestingly, methylation changes induced in response to abiotic stress condition(s) reversed to its original methylation status after stress recovery (Wang et al ., 2011).…”

Genome-wide analysis of cytosine DNA methylation revealed salicylic acid promotes defense pathways over seedling development in pearl millet

“…This method is based primarily on Amplified Fragments Length Polymorphism (AFLP) analysis. 49 It uses two different reactions with MspI/EcoRI, and HpaII/EcoRI. The isoschizomeres recognize the same DNA site 5 0 -CCGG-3 0 with different sensitivity to methylation.…”

Ecological Epigenetics in Marine Metazoans

“…Overall, the emergence for the appreciation of the role of epigenetics in an ecological context has developed in both aquatic and terrestrial systems (Bonduriansky et al, 2012). Studies on plants have dominated the literature on ecological epigenetics (Schrey et al, 2013;Baulcombe and Dean, 2014;Verhoeven et al, 2016), especially in response to stress (Wang et al, 2011;Grativol et al, 2012;Al-Lawati et al, 2016). On the marine side, epigenetic and epigenomic approaches are being used to explore areas such as (1) sources of phenotypic plasticity, as created by differential gene expression (Dixon et al, 2014;Dimond and Roberts, 2016;Marsh et al, 2016), (2) mechanisms involved in development (Riviere et al, 2013), and (3) a possible rapid response to anthropogenic environmental change (Putnam et al, 2016).…”