As sessile organisms, plants are continuously exposed to environmental stress. Since stress avoidance is not an option, plants evolved as organisms that very efficiently acclimate and adapt to stress. Although the mechanism of stress response may be genetically predefined, organisms are capable to modify their responses with various epigenetic changes. Plants are especially flexible in this respect since they do not have a predetermined germ line and thus life experiences in the form of epigenetic memory can be more efficiently passed to the progeny. Indeed, the plasticity of plant phenotypes can not be simply explained by genetic changes such as point mutations, deletions, insertions and gross chromosomal rearrangements. Many environmental stresses persist for only short time, typically one or several plant generations. It is thus possible that plants carry the memory of these short-time environmental exposures. Recent reports suggest that such response, often referred to as transgenerational memory, may include epigenetic mechanisms. Epigenetic regulations include heritable but reversible changes in gene expression caused by changes in DNA cytosine methylation, histone modifications and expression of small non-coding RNAs. The heritability of reversible epigenetic modifications that regulate gene expression without changing DNA sequence makes them an attractive alternative mechanism.
In this Research Topic, we would like to present various phenomena associated with acquisition of stress tolerance and describe the possible role of physiological, genetic and epigenetic mechanisms. We are seeking the input from various groups of scientists, including those working in the areas of plant physiology, genetics, epigenetics, molecular biology and various related field. We would like to describe the genetic and epigenetic mechanism of stress response in somatic cells as well as in gametes. Main emphasis should be the transgenerational response and heritable genetic and epigenetic changes in acclimating and adapting plants.
ILLUSTRATION: Regeneration of canola plants from hypocotyl