Self-grafting-induced epigenetic changes leading to drought stress tolerance in tomato plants

Abstract

Grafting is widely used as a method to increase stress tolerance in good fruiting lines of Solanaceae plants. However, little is known about how grafting, affects epigenetic modifications and leads to stress tolerance, especially within the same line. Here, we studied the effects of self-grafting in tomato plants on histone and DNA modifications and changes in gene expression related to drought stress. We found that at the 3-leaf stage, one week after self-grafting, histone H3 K4 trimethylation and K27 trimethylation changes were observed in more than 500 genes each, and DNA methylation changes in more than 5,000 gene regions at the shoot apex compared to the non-grafted control. In addition, two weeks after the epigenomic changes, global expression changes continued to be observed at the shoot apex in several genes related to the metabolic process of nitrogen compounds, responses to stimulus, chromosome organization, cell cycle-related genes, and regulation of hormone levels. Finally, these grafted seedlings acquired remarkable drought tolerance, suggesting that epigenomic modifications during the wound-healing process mitigate stress tolerance in tomato plants.

Redox regulation of chromatin remodelling in plants

“…On the contrary, heat stress resulted in depletion of the H3K9me2 mark in Arabidopsis (Pecinka et al, 2010). Interestingly, self-grafting in tomato plants that led to acquisition of drought tolerance was accompanied with deposition of H3K4me3 and H3K27me3 marks on the majority of differentially methylated genes (Fuentes-Merlos et al, 2023). The accumulation of these histone marks can be partially governed by perturbations of the cellular redox homoeostasis triggered by the wounding process.…”