Epigenetic regulations under plant stress: A cereals perspective

In the era of global climate change, abiotic stresses are the most prominent factors limiting crop productivity worldwide. Besides the gradual increase in global mean temperature, altered weather patterns, frequency of heat spikes, and drought episodes are some of the major consequences of changing climate, which threatens global food security. This problem warrants immediate attention and could be solved by developing climate-resilient crops. The crucial step towards growing such crops is understanding the complex molecular mechanism of abiotic stress regulation in field crops. The abiotic stresses in plants are broadly regulated by their genetic makeup and stress-responsive genes and their control epigenetically. Many reports are available on genetic regulation directly linked with stress-responsive genes, but only limited progress has been made in epigenetic regulation. Therefore, this review will focus on different epigenetic modifications, significant players, the complexity of interactions, and their role in stress-resilience in plants, specifically major cereals. Further, we have explored the research advancements and gaps in plant epigenome studies that will complete the relationship among the SNP–SMP–gene expression triplets. We have also explored the technological advancements combinations such as the integration of gene editing technology of CRISPR-Cas9 and the methylation editing technology of CRISPR-dCas9 for the process of molecular design for cereal ideotypes. Overall, this review will highlight the importance of epigenetic regulation to understand the complex nature of abiotic stresses and combinations while highlighting research gaps, particularly for cereals, to design future climate-smart crops.