Epigenetic memory and growth responses of the clonal plant

Abstract

The responses of plants to recurrent stress may differ from their responses to a single stress event. In this study, we investigated whether clonal plants can remember past environments. Parental ramets of Glechoma longituba (Nakai) Kuprian were exposed to UV-B stress treatments either once or repeatedly (20 and 40 repetitions). Differences in DNA methylation levels and growth parameters among parents, offspring ramets and genets were analysed. Our results showed that UV-B stress reduced the DNA methylation level of parental ramets, and the reduction was enhanced by increasing the number of UV-B treatments. The epigenetic variation exhibited by recurrently stressed parents was maintained for a long time, but that of singly stressed parents was only short-term. Moreover, clonal plants responded to different UV-B stress treatments with different growth strategies. The one-time stress was a eustress that increased genet biomass by increasing offspring leaf allocation and defensive allocation in comparison to the older offspring. In contrast, recurring stress was a distress that reduced genet biomass, increased the biomass of storage stolons, and allocated more defensive substances to the younger ramets. This study demonstrated that the growth of offspring and genets was clearly affected by parental experience, and parental epigenetic memory and the transgenerational effect may play important roles in this effect.

Clonal Parental Effects on Offspring Growth of Different Vegetative Generations in the Aquatic Plant Pistia stratiotes

“…These results support the first hypothesis that parental effects could impact offspring growth of different vegetative generations of clonal plants. Similarly, previous studies have shown that parental environment effects can persist across vegetative generations in clonal plants (e.g., González et al, 2017;Dong et al, 2018b;Portela et al, 2020;Zhang et al, 2021). Our results suggest that paternal effects are fast in clonal plants as the vegetative reproduction is rapid.…”

Parental UV-B radiation regulates the habitat selection of clonal

“…Moreover, shaded parents of P. persicaria produced offspring with increased fitness in shade as well as a greater competitive impact on plant neighbours (Baker et al 2019). Our previous study also suggested that the parental ramets of clonal G. longituba could record their UV-B radiation experience and form epigenetic memory via a decrease in DNA methylation levels, the growth of offspring and genets was clearly affected by parental experience (Zhang et al 2021).…”

“…At the end of the experiment, the biomass of parental ramets was improved by low UV-B radiation (5 μW cm −2 ), which was related to the eustress effects of low-dose UV-B stress. Eustress is an activating, stimulating stress that is a positive element in plant development; when a plant experiences eustress, its metabolism is adjusted, and the plant acclimates to the new environment (Zhang et al 2021); thus, the parental biomass was increased by this mild, elastic UV-B radiation. Furthermore, although only parental ramets were exposed to UV-B radiation, the growth of the parent as well as the genets was influenced.…”

“…The 'maternal effects' of the parental environment can persist across offspring generations and influence the phenotype and fitness of progeny (Galloway 2005; Louâpre et al 2012;González Besteiro and Ulm 2013;González et al 2017;Dong et al 2018Dong et al , 2019. Because of the asexual reproduction of clonal plants, they have a greater ability than nonclonal plants to 'remember' the environmental events of their parent (Zhang et al 2021). Therefore, maternal effects induced by the parental environment have been reported for several clonal plants in recent years.…”

“…The effect of parental UV-B on the growth of offspring ramets in a heterogeneous UV-B environment was investigated in our previous studies on Glechoma longituba (Quan et al 2021;Zhang et al 2021). The results suggested that parental UV-B exposure strongly influenced the growth and foraging behaviour of clonal offspring.…”