Effect of salinity on DNA methylation and antioxidant phenolic compounds of wild watercress (Rorippa nasturtium aquaticum)

Epigenetic changes are involved in plant responses to stress. Cytosine methylation is one of the most important epigenetic changes, regulating gene expression. In this paper, the MSAP (methylation-sensitive amplification polymorphism) method was used to find out how the watercress (Rorippa nasturtium aquaticum) genome changed in response to 0, 60, 80, and 100 mM NaCl and how that affected phenylalanine ammonium lyase (PAL) activity, phenolic content, and antioxidant capacity. The results showed an inverse correlation between methylation levels and PAL activity and the contents of total phenolics and flavonoids, indicating salt stress-induced reprogramming of the methylation pattern of watercress, which has a negative effect on the synthesis of phenolics. The results revealed a significant decrease in phenolic contents and antioxidant activity under low and moderate salinity compared to control and an increase under strong salinity compared to moderate salinity. The findings of this study contribute to our understanding of the reprogramming of DNA methylation under salinity and its effect on watercress phenolic metabolism.