Epigenetic modifications in plants under adverse conditions: Agricultural applications

Abstract

Changing climatic conditions worldwide and considerable decrease in agricultural land area together with rapidly increasing population and therefore increase in food production present a significant challenge to plant breeding and crop improvement programs. Genetic engineering for stress tolerant and nutritionally good crops is a promising area which permits the fast improvement of economically important crops. The attention has also drawn toward elucidating the mechanisms that could allow genetically identical cells or even whole organisms to achieve and maintain different terminal phenotypes. This was accomplished by using different nongenetic or epigenetic determinants that could modify gene expression heritably (mitotically and/or meiotically) and reversibly (without changing the gene sequence encoded in DNA). These epigenetic determinants/marks are enzyme-mediated chemical modifications of DNA and DNA-associated proteins. They include DNA methylation, histone modifications, nucleosome positioning, and small (sm) RNAs. Epigenetic marks modify the properties of chromatin and change gene transcriptional states on the scale from the entire genome to a single specific gene. These marks allow for greater genome plasticity which results in better adaptation of plants to changing environmental conditions.