Explore The Relation Between MCHH Island And Gene Expression In Rice And Arabidopsis Thaliana

In plant,DNA methylation occurs primarily in three sequence types:CG,CHG and CHH.Different types of cytosine methylation are catalyzed by different DNA methyltransferases.In the process of DNA methylation research,DNA methylation has been found to have important regulatory effects on gene expression.The long-standing understanding of the relationship between DNA methylation and gene expression has focused on the inhibition of gene expression by DNA methylation.But people still don't know enough about the relationship between DNA methylation status and gene expression.In the 2018 Steven E.Jacobsen laboratory,in the study of DNA methylation in Arabidopsis thaliana,it was found that related proteins can interact with CHH methyl group and promote the expression level of low expression genes.This study gives us a deeper understanding of the relationship between hypermethylation and gene expression.The regions with high CHH methylation levels have been referred as mCHH islands in previous studies and are typically around 100 bp.The study found that CHH methylation near the gene showed a positive correlation with gene expression levels.However,the relationship between high CHH methylation status and gene expression in different species and different tissues of the same species,and the changes in these high CHH methylation regions and their effects on gene expression under different abiotic stresses remain unclear.Our study utilized a rice chimera Epi-If produced by tissue culture.Its phenotype was caused by a change in the expression of the LOC_Os01g41370 gene.Further studies revealed that the overexpression of this gene in the chimeric mutant was associated with the presence of the mCHH island downstream of the gene,which further deepened our understanding of mCHH island function.On this basis,in order to further understand the situation of mCHH island in different plants and different tissues,and the effect of mCHH island on gene expression,this study integrates the epigenetics and transcriptome data of rice and Arabidopsis thaliana under different tissue and abiotic stresses and bioinformatics-based methods was used to explore changes in mCHH island and the relationship between mCHH island and gene expression.We found that in both plants,mCHH islands are concentrated in the vicinity of the gene,and mCHH island is dynamically altered in different tissues.mCHH island near genes in rice is associated with increased expression levels of low-level expressed genes in most tissues.We further found that different stresses have different effects on mCHH island,and the emerging mCHH island under the stress condition in rice has two-way regulation of gene expression.Through this study,one can have a comprehensive understanding of mCHH island in the monocotyledonous model organism rice and dicotyledonous model organism Arabidopsis thaliana and understand the dynamic changes of mCHH island and its biological significance from the perspective of plant development time and different tissue space.