Intraspecific DNA methylation polymorphism in the non-edible oilseed plant castor bean

Investigation of the relationships of phenotypic and epigenetic variations might he a good way to dissect the genetic or molecular basis of phenotypic variation and plasticity in plants, Castor bean （Ricinus cornraunis L）, an important non-edible oilseed crop, is a mono-species genus plant in the family Euphorbiaceae. Since it displays rich phenotypic variations with low genetic diversity, castor bean is a good model to investigate the molecular basis of phenotypic and epigenetic variations. Cytosine DNA methylation represents a major molecular mechanism of epigenetic occurrence. In this study, epigenetic diversity of sixty landrace accessions collected worldwide was investigated using the methylation- sensitive amplification polymorphism （MSAP） technique, Results showed that the epigenetic diversity （based on the polymorphism of DNA methylated loci） exhibited a medium variation （Ne = 1.395, He = 0.242, I = 0.366） at the population level though the variation was great, ranging from 3,80% to 3431% among accessions. Both population structure analysis and the phylogenetic construction （using the neighbor-joining criteria） revealed that the two main clades were identified, but they did not display a distinct geographic structure, After inspecting the location of polymorphic methylated loci on genome we identified that the polymorphic methylated loci occur widely in nuclear and organelle genomes. This study provides new data to understand phenotypic and epigenetic variations in castor bean,

Genetic and Epigenetic Diversities Shed Light on Domestication of Cultivated Ginseng （Panax ginseng）

Chinese ginseng （Panaxginseng） is a medically important herb within Panax and has crucial cultural values in East Asia. As the symbol of traditional Chinese medicine, Chinese ginseng has been used as a herbal remedy to restore stamina and capacity in East Asia for thousands of years. To address the evolutionary origin and domestication history of cultivated ginseng, we employed multiple molecular approaches to investigate the genetic structures of cultivated and wild ginseng across their distribution ranges in northeastern Asia. Phylogenetic and population genetic analyses revealed that the four cultivated ginseng landraces, COMMON, BIANTIAO, SHIZHU, and GAOLI （also known as Korean ginseng）, were not domesticated independently and Fusong Town is likely one of the primary domestication centers. In addition, our results from population genetic and epigenetic analyses demonstrated that cultivated ginseng maintained high levels of genetic and epigenetic diversity, but showed distinct cytosine methylation patterns compared with wild ginseng. The patterns of genetic and epigenetic variation revealed by this study have shed light on the domestication history of cultivated ginseng, which may serve as a framework for future genetic improvements.

DNA methylation polymorphism and stability in Chinese indica hybrid rice

Conventional rice breeding has long focused on exploiting the DNA sequence diversity.However,epigenetic diversity,reflected particularly in DNA methylation,can also contribute to phenotypic variation and should not be overlooked in rice breeding.In this study,20 parental lines of indica rice,which are widely used in hybrid rice breeding in China,were analyzed to investigate variations of DNA methylation and its inheritance.The results revealed a wide diversity in DNA methylation among these breeding lines.A positive correlation was seen between DNA methylation and genetic diversity.Furthermore,some of the methylated DNA was inherited in the subsequent generation,regardless of whether they were produced by selfing or hybrid-crossing.This study provides insight into the methylation patterns in rice,and suggests the importance of epigenetic diversity in rice breeding.