GSE115610
Genome Wide Methylation Analysis of Organellar DNA in MR219 Indica Rice Cultivar
Purpose:  The chloroplast DNA has not been primiarly analyzed in rice plants before. Hence, the objective of this study is to analyze and compare the differential methylation of chloroplast DNA in MR219 indica rice across different tissues and different developmental stages. Methods:  We prepared a total of nine sodium bisulfite treated DNA libraries from three developing grain tissues, three leaf tissues at ripening stage and three leaf tissues at vegetative stage and sequenced them in Illumina Miseq platform. We performed quality trimming, alignment followed by methylation calling and differential methylation analysis using Trimmomatic v36, Bismark v16.3 and SeqMonk v40.0 on the sequencing data obtained. Statistical analysis was carried out in SeqMonk software and further validated in SPSS statistical software v22.2. Results: With an optimized data analysis workflow, we mapped around average of 26000 reads to chloroplast genome.  Differential CpG and CHG methylation in SeqMonk v40.0 revealed that MR219 chloroplast DNA is differentially methylated in grain and leaf tissues and across vegetative stage and ripening stage in the leaf tissues. Chloroplast DNA from leaf at ripening stage was most methylated, followed by grain tissue and lastly leaf tissue from vegetative stage. Conclusions: Overall, it can be concluded that the organellar DNA in MR219 rice are differentially methylated at different tissues and across different developmental stages. The chloroplast DNA was most methylated in the  leaf at ripening stage, followed by grain at ripening stage and leaf at vegetative stage. The functional significance of the differential methylation observed in this study needs to be investigated. Overall design: MR219 rice developing grain at ripening stage, leaf tissue at ripening stage and leaf tissue at vegetative stage sequencing data were generated from Illumina Miseq in triplicates.