Cadmium (Cd) contamination of agricultural soils threatens crop productivity and food safety by disrupting physiological and molecular processes in plants. Increasing evidence indicates that epigenetic regulation, including DNA methylation, histone modifications, and emerging epitranscriptomic marks such as RNA methylation, plays a crucial role in coordinating plant responses to Cd stress. In parallel, plant-associated microbiomes have emerged as influential modulators of metal uptake, antioxidant capacity, hormone signaling, and stress resilience. Yet the mechanisms by which microbiome-derived signals intersect with host chromatin and transcriptome regulation under Cd exposure remain poorly understood. This review synthesizes current knowledge on plant epigenetic responses to Cd stress and critically examines how microbial metabolites, phytohormones, and redox-active compounds shape plant regulatory networks. Network-based ecological studies reveal that increased microbial community complexity and cooperative interactions are consistently associated with reduced Cd accumulation and enhanced plant performance, suggesting that microbial organization itself may represent an additional regulatory layer influencing plant responses. Despite compelling conceptual links, direct experimental evidence connecting microbiome signals to stable epigenetic or epitranscriptomic reprogramming under Cd stress remains limited. To date, only limited experimental studies have demonstrated causal relationships between microbial cues and host DNA or RNA methylation dynamics in Cd-exposed plants, highlighting clear mechanistic potential while also underscoring remaining knowledge gaps. By integrating physiological, ecological, and chromatin-level perspectives, this review identifies key unanswered questions and outlines future research directions to establish causal links between microbial community dynamics, epigenetic regulation, and long-term Cd stress adaptation in plants.
Cengiz Kaya (Thu,) studied this question.