Chromatin modifications and epigenetics play important roles in a number of plant processes including developmental regulation, responses to environmental stimuli and adaptation. The concept of ‘chromatin modifications’ describes biochemical changes to chromatin state such as the specific type or placement of histones, modifications of DNA or histones, or changes in the specific proteins or RNA that is associated with a region. The term ‘epigenetic’ is often used to describe a variety of unexpected patterns of gene regulation or inheritance. Key aspects of this definition are the concept of heritability (stable transmission of gene expression states through mitotic or meiotic cell divisions) and an independence from DNA sequence changes. Although many examples of epigenetics involve chromatin changes, those changes including histone variants, histone modifications and DNA methylation are not always heritable or are influenced by genetic changes leading to complications in generically equating chromatin and epigenetics. A more conservative use of the terms ‘chromatin modifications’ and ‘epigenetics’ can be useful in delineating biochemical mechanisms of regulation from inheritance patterns for altered chromatin states. Here we highlight examples in which chromatin modifications and/or epigenetics contribute to important plant processes.
Via Jennifer Mach, Loïc Lepiniec