Retrospective and perspective of plant epigenetics in China

Epigenetics refers to the study of heritable changes in gene function that do not involve changes in the DNA sequence. Such effects on cellular and physiological phenotypic traits may result from external or environmental factors or be part of normal developmental program. In eukaryotes, DNA wraps on a histone octamer(two copies of H2A, H2B, H3 and H4) to form nucleosome, the fundamental unit of chromatin. The structure of chromatin is subjected to a dynamic regulation through multiple epigenetic mechanisms, including DNA methylation, histone posttranslational modifications(PTMs), chromatin remodeling and noncoding RNAs. As conserved regulatory mechanisms in gene expression, epigenetic mechanisms participate in almost all the important biological processes ranging from basal development to environmental response. Importantly, all of the major epigenetic mechanisms in mammalians also occur in plants. Plant studies have provided numerous important contributions to the epigenetic research. For example, gene imprinting, a mechanism of parental allele-specific gene expression, was firstly observed in maize; evidence of paramutation, an epigenetic phenomenon that one allele acts in a single locus to induce a heritable change in the other allele, was firstly reported in maize and tomato.Moreover, some unique epigenetic mechanisms have been evolved in plants. For example, the 24-nt siRNA-involved RNA-directed DNA methylation(RdDM) pathway is plant-specific because of the involvements of two plant-specific DNA-dependent RNA polymerases, Pol IV and Pol V. A thorough study of epigenetic mechanisms is of great significance to improve crop agronomic traits and environmental adaptability. In this review, we make a brief summary of important progress achieved in plant epigenetics field in China over the past several decades and give a brief outlook on future research prospects.We focus our review on DNA methylation and histone PTMs, the two most important aspects of epigenetic mechanisms.

Centromere Epigenetics in Plants

The centromere is an essential chromosome site at which the kinetochore forms and loads proteins needed for faithful segregation during the cell cycle and meiosis（Houben et al., 1999;Cleveland et al.,2003;Ma et al.,2007;Birchler and Han,2009）.Centromere specific sequences such as tandem repeats or transposable elements evolve quickly both within and between the species but have conserved kinetochore proteins（Henikoff and Furuyama,2010）.

Recognizing importance of epigenetic and epigenomic regulations of medicinal plants

Epigenetics is the study of heritable changes in gene function that do not involve changes in the DNA sequence. Epigenetics most often denotes changes in a chromosome that affect gene activity and expression, and also can be used to describe any heritable phenotypic change. Such effects on cellar and physiological

Mechanism for winter cold-mediated epigenetic silencing of a potent floral repressor in plants

Subject Code:C02With the support by the Chinese Academy of Sciences(CAS),the research team of Plant Environmental Epigenetics led by Prof.He Yuehui(何跃辉)at the Shanghai Center for Plant Stress Biology,CAS and CAS Center for Excellence of Molecular Plant Sciences,discovered a molecular epigenetic mechanism underlying how winter cold enables plants to flower in spring,which was published in Nature Genetics(2016,48:1527—1534).