Role of the RdDM pathway in the expression of transgenerational vernalization effects in Arabidopsis thaliana seeds

MARÍA CLARA FONTANA; VIRGINIA IBARRA; GABRIELA A AUGE

Congreso; 13th Triennial Meeting of the International Society for Seed Science; 2021

International Society for Seed Science

Plants are able to sense environmental changes happening throughout their life cycles and thoseexperienced by previous generations, developing strategies to adapt to those changes and increasing progeny’s survival. Thus, developmental transitions are under strong selective pressure as they need to be finely timed to environmental conditions that are optimal for survival. Understanding these responses and their underlying mechanisms is key to assess life cycle adjustment to climate change in dynamical plant communities. In Arabidopsis thaliana, transgenerational regulation of phenotypic plasticity involves an epigenetic component: transgenerational responses to temperature changes have been associated with the function of small RNA synthesis genes and with DNA methylation frequency changes inherited by the progeny, suggesting a role for the RNA-directed DNA methylation pathway (RdDM). Vernalization (a period of cold that signals winter) also shows transgenerational effects that have the potential to influence ecological and evolutionary processes. To understand the process by which non-stressing seasonal environmental changes experienced by previous generations influences the progeny, we characterized responses to maternal vernalization by exploring the environmental influence on key progeny traits (seeds traits, dormancy, germination and seedling development), and correlated those responses with the RdDM pathway by using pathway mutants. Total reproductive biomass production, seed size and seedling development were affected by environmental cues experienced by mother plants, and some RdDM mutants mediated this effect. Furthermore, progeny germination and dormancy were affected by the maternal environment as well and RdDM mutants influenced transgenerational plasticity. Our results show that environmental cues experienced by plants even early in their life cycles have a strong influence on early traits of subsequent generations. These effects are at least in part mediated by an epigenetic mechanism (RdDM), showing a complex interaction between environments experienced by different generations and epigenetic memory.