Recurrent Water Deficit and Epigenetic Memory in Medicago sativa L. Varieties

Yannis E Ventouris,Styliani N Chorianopoulou,Dimitrios N Vlachostergios,Evangelia V Avramidou,Eleni Tani,Eleni M Abraham,Georgios Papadopoulos,Aliki Kapazoglou

doi:10.3390/app10093110

Abstract

Global DNA methylation changes in response to recurrent drought stress were investigated in two common Greek Medicago sativa L. varieties (Lamia and Chaironia-Institute of Ιndustrial and Forage Crops). The water deficit was implemented in two phases. At the end of the first phase, which lasted for 60 days, the plants were cut at the height of 5 cm and were watered regularly for two months before being subjected to the second drought stress, which lasted for two weeks. Finally, the following groups of plants were formed: CC (controls both in phase I and phase II), CD2 (Controls in phase I, experiencing drought in phase II), and D1D2 (were subjected to drought in both phase I and phase II). At the end of phase II, samples were taken for global DNA methylation analysis with the Methylation Sensitive Amplification Polymorphism (MSAP) method, and all plants were harvested in order to measure the fresh and dry weight of roots and shoots. The variety Lamia responded better, especially the D1D2 group, compared to Chaironia in terms of root and shoot dry weight. Additionally, the shoots of Lamia had a constant water status for CD2 and D1D2 group of plants. According to DNA methylation analysis by the MSAP method, Lamia had lower total DNA methylation percentage after the second drought episode (D1D2) as compared to the plants CD2 that had experienced only one drought episode. On the other hand, the total DNA methylation percentage of Chaironia was almost the same in plants grown under recurrent drought stress conditions compared to control plants. In conclusion, the decrease of DNA methylation of Lamia stressed plants probably indicates the existence of an epigenetic mechanism that may render drought tolerance.

Highlights

Climate changes affect crop production as well as the availability of natural resources, such as land and water
According to the mean value of polymorphic alleles that were provided from the R software with the MSAP_calc program for each category of alleles (h, m and u), Lamia controls presented a 68.57% percentage of total methylation, while a decrease of the total methylation percentage was observed in Lamia D1D2 (61.92%) and CD2 (62.31%)
The total methylation in the leaves of Chaironia controls reached a percentage of 71.12%, whereas a decrease of total methylation was noticed in Chaironia CD2 treatment (58.23%), but not in the case of Chaironia D1D2 (72.36%) (Table 3, Figures 6 and 7)

Summary

Introduction

Climate changes affect crop production as well as the availability of natural resources, such as land and water. More than 60% of the annual yield fluctuations of important crops have been attributed to. Sci. 2020, 10, 3110 climatic variability [1]. The release of new, improved varieties combining high productivity and increased adaptability to the ongoing environmental changes has become an imperative [2]. Recent findings highlight a new source of heritable variation in plants, derived from epigenetic regulations, that play an essential role in directing the expression of agronomically important traits and adaptation of plants to a changing environment due to global climate change [3]

Methods

Results

Conclusion