The Role of DNA Methylation in Plant Biotic Stress Responses
TL;DR
Recent advances in understanding dynamic changes in DNA methylation in plants exposed to a wide range of biotic threats are summarized, highlighting how pathogen interactions trigger DNA methylation changes that can either activate plant defense mechanisms or be manipulated by pathogens to promote host susceptibility.
Abstract
DNA methylation, a key epigenetic modification, is an important regulator of plant gene expression, coordinating development and responses to environmental signals. DNA methylation includes both cytosine methylation and adenine methylation. Cytosine methylation has been studied in plant immunity, while adenine methylation is emerging as a novel regulator. As part of its role in regulating gene expression, DNA methylation, so far mainly cytosine methylation, exhibits a dynamic behavior during biotic stresses. Indeed, several reports have explored the targets and regulatory capacity of DNA methylation-associated responses. This review summarizes recent advances in understanding dynamic changes in DNA methylation in plants exposed to a wide range of biotic threats, including viruses, fungi, oomycetes, bacteria, and insects, with examples on horticultural crops such as tomato, chrysanthemum, and citrus. We highlight how pathogen interactions trigger DNA methylation changes that can either activate plant defense mechanisms or be manipulated by pathogens to promote host susceptibility. We also discuss how pathogen effectors target host methylation machinery and the molecular basis of transgenerational epigenetic immune memory. Collectively, the evidences underscore DNA methylation as a critical battleground in plant-pathogen interactions across diverse plant species, pointing to its potential as a target for innovative crop improvement strategies.