Role of Silicon in Mediating Salt Stress Responses in Arabidopsis Methylation Mutants

Purpose The growing prevalence of soil salinity presents a significant threat to agriculture production on a global scale. Previous studies on salt stress, shown that silicon (Si) has an alleviating effect on plants exposed to stress. However, the results of the alleviating effect of Si on epigenetic level is not yet understood. In this study, we tried to understand how methylation mechanisms affect the alleviating effect of Si by testing on Arabidopsis epigenetic mutants (met1-7, drm2-2 and ros1-4). Methods The Col-0 and mutant plants were exposed to silicon and NaCl simultaneously and separately during two weeks. After that in order to see the physiological effects of Si on methylation mutants, which is known to be effective in antioxidant pathways of Col-0 plants, osmolyte accumulation and membrane damage were analyzed and to see the effects at the molecular level, the expression profiles of the CSD2, CAT3 and APX1 genes and global methylation changes were analyzed. Results As a general result of the osmolyte accumulation, ion leak, global methylation and gene expression analyzes performed in this study, it was determined that salt stress also had negative effects on Arabidopsis epigenetic mutants. It was concluded that the mitigating effect of Si on NaCl stress was most clearly determined as a result of global DNA methylation analyses. Conclusions It was found that treating Arabidopsis methylation mutants with Si during salt stress could improve the plants' ability to withstand salt. The results of this study provide information about the alleviating effect of Si based on methylation of separate and co-exposure to Si and NaCl, and also provide an epigenetic perspective to explain the mechanisms of Si improving plant durability under stress conditions.