This Entry Collection focuses on current progress in understanding the role of chromatin structure, its modifications and remodeling in developmental and physiological processes. Eukaryotic genomes are packed into the supramolecular nucleoprotein structure of chromatin. Therefore, our understanding of processes such as DNA replication and repair, transcription, and cell differentiation requires understanding the structure and function of chromatin. While the nucleotide sequence of the DNA component of chromatin constitutes the genetic material of the cell, the other chromatin components (and also modifications of bases in the DNA itself) participate in so-called epigenetic processes. These processes are essential, e.g., in ontogenesis or adaptation to environmental changes. Therefore, epigenetics is particularly important (and elaborated) in plants that show a high developmental plasticity and, as sessile organisms, display an enormous capacity to cope with environmental stress. In these processes, epigenetic mechanisms show a crosstalk with plant signaling pathways mediated by phytohormones and redox components. You are welcome to read examples of current research and review articles in this hot research topic.
The ever-increasing interest in epigenetics comes from the fact that in the diverse life situations of organisms, e.g., in cell differentiation, developmental decisions, or responses to biotic and abiotic stresses, it is primarily the reprogramming of the regulation of the existing genetic information, rather than its direct change, that solves the problem. Epigenetic mechanisms allow the organism to channel the appropriate response through diverse particular molecular tools modifying distinct levels of the structure of chromatin. Chromatin is thus marked with certain signals, for example, DNA methylation, posttranslational modifications of histones, incorporation of specific histone variants, or chromatin remodeling. These signals, written by respective enzymes and complexes, termed as epigenetic writers (e.g., DNA methyltransferases, histone methyltransferases, and histone acetyltransferases) have to find their readers—biomolecules recognizing the specific mark, and erasers which are capable of resetting the program. Recent data suggest a deep interconnection of individual epigenetic players, which frequently act together as components of the same multi-subunit complexes. For example, methylcytosine binding protein MeCP2 (a reader) recruits histone deacetylase (an eraser) and H3K9 histone methyltransferase Suv39h1 (a writer), and in this way reinforces the repressive state of a chromatin region [1][2]. Recent research in plants brings many novel findings elucidating the interdependence of diverse epigenetic mechanisms and their crosstalk with various signaling pathways, including the action of phytohormones and reactive oxygen and nitrogen species. Using these molecular tools, chromatin structure decides which particular set of genes will be active in a particular physiological process.
The special issue “Chromatin, Epigenetics and Plant Physiology” in the International Journal of Molecular Sciences comprises two review articles and eight original research papers (Table 1). All contributions deal with important aspects of epigenetic regulations of crucial cellular processes involved in plant growth and development.
Table 1. Contributors to the special issue “Chromatin, Epigenetics and Plant Physiology”.
Authors | Title | Type |
---|---|---|
Wang et al. [3] | Roles of the INO80 and SWR1 Chromatin Remodeling Complexes in Plants | Review |
Guo et al. [4] | Mutations in the Rice OsCHR4 Gene, Encoding a CHD3 Family Chromatin Remodeler, Induce Narrow and Rolled Leaves with Increased Cuticular Wax | Original Research |
Zhao et al. [5] | Identification and Characterization of Tomato SWI3-Like Proteins: Overexpression of SlSWIC Increases the Leaf Size in Transgenic Arabidopsis | Original Research |
Gratkowska-Zmuda et al. [6] | The SWI/SNF ATP-Dependent Chromatin Remodeling Complex in Arabidopsis Responds to Environmental Changes in Temperature-Dependent Manner | Original Research |
Krispil et al. [7] | The Position and Complex Genomic Architecture of Plant T-DNA Insertions Revealed by 4SEE | Original Research |
Lochmanová et al. [8] |
Different Modes of Action of Genetic and Chemical Downregulation of Histone Deacetylases with Respect to Plant Development and Histone Modifications | Original Research |
Koláčková et al. [9] | Nuclear Disposition of Alien Chromosome Introgressions into Wheat and Rye Using 3D-FISH | Original Research |
Zhang et al. [10] | Identification and Characterization of circRNAs Responsive to Methyl Jasmonate in Arabidopsis thaliana | Original Research |
Boudichevskaia et al. [11] | Depletion of KNL2 Results in Altered Expression of Genes Involved in Regulation of the Cell Cycle, Transcription, and Development in Arabidopsis | Original Research |
R.M.S. et al. [12] | Redox Components: Key-Regulators of Epigenetic Modifications in Plants | Review |