Epigenetic Control of Plant Response to Heavy Metals

Abstract

Plants are sessile organisms that must adapt to environmental conditions, such as soil characteristics, by adjusting their development during their entire life cycle. In case of low-distance seed dispersal, the new generations are challenged with the same abiotic stress encountered by the parents. Epigenetic modification is an effective option that allows plants to face an environmental constraint and to share the same adaptative strategy with their progeny through transgenerational inheritance. This is the topic of the presented review that reports the scientific progress, up to date, gained in unravelling the epigenetic response of plants to soil contamination by heavy metals and metalloids, collectively known as potentially toxic elements. The effect of the microbial community inhabiting the rhizosphere is also considered, as the evidence of a transgenerational transfer of the epigenetic status that contributes to the activation in plants of response mechanisms to soil pollution.

Impact of Heavy Metal Pollution in the Environment on the Metabolic Profile of Medicinal Plants and Their Therapeutic Potential

“…(b) Stress-responsive genes: Hormonal regulation extends its influence to the expression of stress-responsive genes, constituting a tightly orchestrated network of molecular responses within medicinal plants. Heavy metals induce changes in gene expression patterns, activating or suppressing specific genes involved in antioxidant defense [ 142 , 143 ]. This dynamic modulation of stress-responsive genes shapes the adaptive responses of the plant to metal stress, fine-tuning its capacity to cope with oxidative challenges.…”

“…(b) Transgenerational effects: The implications of epigenetic modifications extend beyond immediate responses, with transgenerational effects becoming a noteworthy facet of heavy metal-plant interactions [ 146 , 147 ]. The heritability of epigenetic changes contributes to transgenerational responses to heavy metals, influencing the adaptability of plant populations over successive generations in metal-contaminated environments [ 142 , 143 ]. The induced changes in DNA methylation and histone modifications can be passed down from one generation to the next, imprinting a molecular memory within the plants genetic heritage.…”

“…These changes in gene expression, driven by transcriptional regulation, have a chain reaction on the levels of specific bioactive compounds. The dynamic interplay between the plants genetic structure and its response to heavy metal stress thus becomes a critical determinant, shaping the overall therapeutic potential of medicinal plants in the midst of environmental challenges [ 127 , 143 ].…”

From genes to ecosystems: Decoding plant tolerance mechanisms to arsenic stress

“…Epigenetic regulation plays a pivotal role in plant responses to As stress, modulating gene expression without altering the underlying DNA sequence [ 134 , 135 ]. DNA methylation, a key epigenetic modification, has been shown to alter gene expression patterns in rice in response to heavy metals [ 136 ].…”

“…It has been reported that ROS homeostasis and signaling mediate epigenetic mechanisms in heavy metal stress [ 141 ]. ROS may influence the activity of chromatin-remodeler enzymes by changing their post-translational modifications and, therefore, their activity [ 135 ]. Furthermore, plants can retain an 'epigenetic memory' of As exposure, which influences their stress responses and can be passed on to subsequent generations.…”