Transgenerational Effects of Stress Exposure on Offspring Phenotypes in Apomictic Dandelion

Abstract

Heritable epigenetic modulation of gene expression is a candidate mechanism to explain parental environmental effects on offspring phenotypes, but current evidence for environment-induced epigenetic changes that persist in offspring generations is scarce. In apomictic dandelions, exposure to various stresses was previously shown to heritably alter DNA methylation patterns. In this study we explore whether these induced changes are accompanied by heritable effects on offspring phenotypes. We observed effects of parental jasmonic acid treatment on offspring specific leaf area and on offspring interaction with a generalist herbivore; and of parental nutrient stress on offspring root-shoot biomass ratio, tissue P-content and leaf morphology. Some of the effects appeared to enhance offspring ability to cope with the same stresses that their parents experienced. Effects differed between apomictic genotypes and were not always consistently observed between different experiments, especially in the case of parental nutrient stress. While this context-dependency of the effects remains to be further clarified, the total set of results provides evidence for the existence of transgenerational effects in apomictic dandelions. Zebularine treatment affected the within-generation response to nutrient stress, pointing at a role of DNA methylation in phenotypic plasticity to nutrient environments. This study shows that stress exposure in apomictic dandelions can cause transgenerational phenotypic effects, in addition to previously demonstrated transgenerational DNA methylation effects.

Epigenetic Variation, Inheritance, and Selection in Plant Populations

“…In apomictic dandelions, Taraxacum officinale, environmentally induced changes in DNA methylation can be transmitted to the progeny (Verhoeven et al 2010). The stress treatments were associated with phenotypic effects in the progeny, but they differed among genotypes and were only partly reproducible in subsequent experiments, indicating a stochastic component (Verhoeven and van Gurp 2012).…”

“…Such epialleles contribute to the phenotypic diversity of a population and, hence, may have a role in adaptation and evolution. Moreover, the formation of certain epialleles may be triggered by the environment, as suggested in several recent plant studies (Molinier et al 2006;Hauben et al 2009;Boyko et al 2010;Kathiria et al 2010;Lang-Mladek et al 2010;Verhoeven and van Gurp 2012). If such effects last for several generations, the modern evolutionary synthesis will have to be expanded.…”

Epigenetic Regulation in Plant Responses to the Environment

“…In dandelions (Taraxacum officinale), the genomewide pattern of DNA methylation is modified if the parental plants are exposed to environmental stress and the progeny show modifications of root/shoot biomass ratio, P content, leaf morphology, and stress tolerance relative to the control. DNA methylation is implicated because chemical suppression of DNA methyltransferase blocks the transgenerational effects (Verhoeven and Van Gurp 2012). A third example involves rice plants subjected to the stress involved in regeneration from tissue culture.…”

Evolutionary and Ecological Responses to Anthropogenic Climate Change

“…(Herrera and Bazaga, 2011) and regulation of flowering time in Arabidopsis (Bastow et al, 2004). These environmentally induced epigenetic modifications can be heritable Verhoeven and van Gurp, 2012) and could potentially play an important role in species responses to rapid, directional climatic change (Bossdorf et al, 2008;Becker and Weigel, 2012).…”