Phenotype Change through Light Manipulation and DNA de-methylation

Epigenetics is the study of heritable changes in observable characteristics in an organism (phenotype) that occur without a change in the DNA sequence. For example, although clones of a plant species have identical DNA, they may respond differently to shading stress due to variation in expression of shade-tolerance genes among individuals. These variations in gene expression may be controlled by DNA methylation, but the effect of DNA methylation on plant phenotype in different environments is poorly understood. In this study, we examine the relationship between quantity and quality of light and its effect on several growth traits. This is accomplished by treating several lines of Arabidopsis thaliana plants with a crude de-methylating agent (5-azacytidine), and comparing their phenotypes to those of untreated plants. Eight lines of treated and untreated A. thaliana plants were grown under three different light conditions- 1) control (created using clear lighting filters), 2) Simulated foliar shade (green lighting filters) and 3) neutral shade (white lighting filters). Our preliminary results show that multiple flower branching, an unusual trait in A. thaliana is more common in treated members than in untreated members of the same line in all light treatments, suggesting that DNA methylation is an important aspect of how plants control their phenotypic expression within a single generation. This study is important because deepening our understanding of how DNA methylation effects species can have important consequences in agriculture and medicine as well as overall health of plants and other organisms