Understanding the Role of DNA Methylation in Regulating Gene Expression during development in Oryza Sativa and Physcomitrella Patens

Abstract

Rice (Oryza sativa), a member of Gramineae family, is a major crop plant that feeds almost newlinehalf of the global human population. In recent years, this plant has emerged as a model newlinesystem for functional genomics studies among the monocot plants. The availability of its newlinecomplete genome sequence, easy transformation protocols and various mutant lines have newlinebeen instrumental in unravelling the genetic and epigenetic molecular mechanisms that newlineregulate gene expressions and various developmental pathways including reproductive newlinedevelopment in rice. However, despite these advances, one of the important epigenetic newlineregulators, the process of DNA methylation, has largely remained unexplored partly newlinebecause of increased complexity in higher plant organization. With the view to get a clearer newlinepicture of the role of this regulatory process and to be able to understand the roles of its newlinemolecular components in modulating gene expression patterns, we selected an early land newlineplant Physcomitrella patens as the second model organism for the present study. P. patens newlineis a simple moss plant with fully sequenced genome. This study in the two model newlineorganisms has provided significant insight into the conservation and diversity among the newlinemethylation machinery components and their evolutionary relationships in land plants. newlineThe objective of this Ph.D. work was to first establish conclusively the role of DNA newlinemethylation in regulating growth, development and differentiation in both, Physcomitrella newlineand O. sativa and then to identify and characterize the core component of the DNA newlinemethylation machinery, cytosine DNA methyltransferases, in these plants. As a first step in newlinethis direction, the effect of global hypomethylation induced by cytidine analog, zebularine, newlineon growth and development of O. sativa and Physcomitrella was examined...