Global variation in DNA methylation in rice plants under salinity reveals tissue and genotype influence

Plants have developed intricate mechanisms to cope with salinity, including epigenetic modifications like DNA methylation, influencing gene expression and phenotypic traits. However, knowledge about gene expression related to DNA methylation in different tissues and rice genotypes are scarce. This study aimed to investigate gene expression involved in DNA methylation in roots and leaves of various rice genotypes under salinity. For this purpose, we tested four rice genotypes (at stage V4) submitted to 150 mM NaCl for 11 days. We analyzed morphophysiological parameters, sodium and potassium concentrations, expression of genes involved in the DNA methylation process, and the overall analysis of DNA methylation in leaves and roots. Our results demonstrate that the sensitive genotype accumulated higher concentrations of sodium in photosynthetically active tissues when compared to the other genotypes, resulting in more damage and mortality. Despite the variation in the expression of genes involved in the methylation process among the four genotypes, a pattern of repression in roots and positive regulation in leaves was observed. Regarding DNA methylation, the response was specific to tissue/genotype. These results enhance our understanding of the epigenetic responses of rice plants to salinity in different tissues and genotypes.