Phenotypic plasticity in plant defense across life stages: Inducibility, transgenerational induction, and transgenerational priming in wild radish

Abstract

As they develop, many plants deploy shifts in antiherbivore defense allocation due to changing costs and benefits of their defensive traits. Plant defenses are known to be primed or directly induced by herbivore damage within generations and across generations by long-lasting epigenetic mechanisms. However, little is known about the differences between life stages of epigenetically inducible defensive traits across generations. To help fill this knowledge gap, we conducted a multigenerational experiment to determine whether defense induction in wild radish plants was reflected in chromatin modifications (DNA methylation); we then examined differences between seedlings and reproductive plants in current and transgenerational plasticity in chemical (glucosinolates) and physical (trichomes) defenses in this species. Herbivory triggered genome methylation both in targeted plants and their offspring. Within one generation, both defenses were highly inducible at the seedling stage, but only chemical defenses were inducible in reproductive plants. Across generations, herbivory experienced by mother plants caused strong direct induction of physical defenses in their progeny, with effects lasting from seedling to reproductive stages. For chemical defenses, however, this transgenerational induction was evident only in adults. Transgenerational priming was observed in physical and chemical defenses, particularly in adult plants. Our results show that transgenerational plasticity in plant defenses in response to herbivore offense differs for physical and chemical defense and changes across plant life stages.

Epigenetic induction may speed up or slow down speciation with gene flow

“…As we allow for adaptive bias in epigenetic induction, our approach to modeling epimutation differs from that of existing models of adaptation with unbiased epimutation (Klironomos et al 2013, Kronholm & Collins 2015. While definitive empirical evidence of adaptively biased epimutation is currently lacking, our approach to modeling adaptively biased epimutation is supported by empirical data that show transgenerational plasticity (Agrawal et al 1999, Beemelmanns & Roth 2017, Galloway & Etterson 2007, Herman & Sultan 2016, Hales et al 2017, Heckwolf et al 2020, Sobral et al 2021), which may be mediated by epigenetic markers, such as methylation.…”

DNA Methylation Can Mediate Local Adaptation and Response to Climate Change in the Clonal Plant Fragaria vesca: Evidence From a European-Scale Reciprocal Transplant Experiment

“…On the contrary, by acting independently of genetic variants, environmentally and stochastically induced epigenetic variants can quickly create novel phenotypes. Importantly, epigenetic variation can be heritable across multiple generations, thus representing another source of heritable variation on which natural selection can operate ( Richards, 2006 ; Hauser et al, 2011 ; McNamara et al, 2016 ; Sobral et al, 2021 ).…”

Differential environmental and genomic architectures shape the natural diversity for trichome patterning and morphology in different Arabidopsis organs

“…Nevertheless, future studies under natural conditions are needed to demonstrate the adaptive processes that might shape trichome pattern diversity. These should address relevant caveats, such as potential trade‐offs and pleiotropic relationships between trichome patterning and water use efficiency, herbivore defense or plant growth, as well as the phenotypic plasticity of these traits (McKay et al, 2003; Sobral et al, 2021; Züst & Agrawal, 2017).…”