How Strawberries Remember and Respond to Heat Stress

Jenn Hoskins
17th May, 2024

How Strawberries Remember and Respond to Heat Stress

Adult Fragaria vesca mother plants previously subjected to heat stress exhibited a significantly earlier and more abundant flowering phenotype compared to untreated control plants. Shown is Figure 5, part b from study.

Image adapted from: López et al. / CC BY (Source)

Key Findings

  • The study focused on woodland strawberry (Fragaria vesca) and examined how heat stress-induced DNA methylation changes are inherited
  • Heat stress-induced DNA methylation changes were found to be heritable primarily through asexual reproduction
  • Clonally propagated daughter plants retained the stress-induced epigenetic changes, suggesting they can "remember" the stress experienced by the parent plant
Understanding how plants respond to stress and whether these responses can be inherited is a crucial area of research, with significant implications for agriculture and biodiversity. A recent study by the Crop Genome Dynamics Group has shed light on this topic by investigating the heritability of heat stress-induced epigenetic and transcriptomic changes in woodland strawberry (Fragaria vesca)[1]. This study is particularly interesting because it explores both sexual and asexual reproduction modes in strawberries, providing a unique perspective on epigenetic inheritance. Epigenetics refers to changes in gene activity that do not involve alterations to the DNA sequence itself but rather modifications like DNA methylation. These changes can be influenced by environmental factors such as stress. Traditionally, it has been thought that such epigenetic changes are largely transient, meaning they do not last beyond the immediate generation that experiences the stress[2]. However, the Crop Genome Dynamics Group aimed to assess whether heat stress-induced DNA methylation changes could be transmitted to subsequent generations through asexual reproduction. Woodland strawberry is an ideal model for this study because it can reproduce both sexually (via self-pollination) and asexually (via clonal propagation). This dual mode of reproduction allows researchers to compare the heritability of epigenetic changes between these two methods. The team exposed strawberry plants to heat stress and then examined the DNA methylation patterns in both the parent plants and their progeny, which were produced through both sexual and asexual means. The findings revealed that heat stress-induced DNA methylation changes were indeed heritable, but primarily through asexual reproduction. In clonally propagated daughter plants, the epigenetic changes were maintained, suggesting that these plants can "remember" the stress experienced by the parent plant. This contrasts with sexual reproduction, where the methylation changes were largely reset, and the offspring did not retain the stress-induced modifications. These results have significant implications. For one, they suggest that asexual reproduction can be a mechanism for plants to retain beneficial stress responses across generations. This could be particularly useful for crops that are clonally propagated, as it may allow them to maintain resilience to environmental stresses without the need for genetic modification. This finding aligns with previous research on clonal crops, which highlighted the importance of maintaining mixed clonal/sexual systems to preserve adaptive potential[3]. Additionally, the study's findings contribute to our understanding of perennial plant behavior. Previous research has shown that perennials like Arabis alpina undergo repeated cycles of vegetative growth and flowering, regulated by genes such as PEP1[2]. The ability of woodland strawberries to retain stress-induced epigenetic changes through clonal propagation may be another example of how perennial plants can adapt to changing environments over multiple seasons. Moreover, the study also resonates with findings on the genetic diversity of clonal populations. For instance, research on Prunus lusitanica, a polyploid species with clonal reproduction, showed that clonal diversity could be maintained through occasional sexual reproduction, mutation, or seed immigration[4]. The current study on strawberries suggests that clonal propagation can also preserve stress-induced epigenetic changes, adding another layer of complexity to how clonal diversity and adaptability are maintained. In summary, the Crop Genome Dynamics Group's study provides valuable insights into the heritability of epigenetic changes in plants, particularly through asexual reproduction. By demonstrating that heat stress-induced DNA methylation changes can be transmitted via clonal propagation, the research opens up new avenues for improving crop resilience and understanding perennial plant behavior. These findings build on previous studies, highlighting the intricate interplay between genetic and epigenetic factors in plant adaptation and evolution.

GeneticsBiochemPlant Science

References

Main Study

1) Epigenomic and transcriptomic persistence of heat stress memory in strawberry (Fragaria vesca)

Published 16th May, 2024

https://doi.org/10.1186/s12870-024-05093-6

Related Studies

2) PEP1 regulates perennial flowering in Arabis alpina.

https://doi.org/10.1038/nature07988

3) The evolutionary ecology of clonally propagated domesticated plants.

https://doi.org/10.1111/j.1469-8137.2010.03210.x

4) Polyploidy and microsatellite variation in the relict tree Prunus lusitanica L.: how effective are refugia in preserving genotypic diversity of clonal taxa?

https://doi.org/10.1111/mec.12194


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