Natural Variation: A Brief History and Why We Should Bother Studying It

During my undergraduate degree, I was working on a project as a research technician when I was first introduced to the topic of intraspecific natural variation (hereafter natural variation). It was this project on natural variation in Arabidopsis, an important model species of the plant biology world, that really fascinated me. This topic broadly informed my Master's and PhD projects, where I’m exploring how natural variation in this species influences the plants' ability to respond to our world’s changing climate. Natural variation can be defined as phenotypic variation within a species that results from spontaneous mutations. But why bother studying natural variation, specifically in Arabidopsis thaliana?

Researchers have been working on Arabidopsis research since the early 1900s and which occupies a wide range of habitats and microclimates globally. There are currently over 7000 accessions of this species currently available in stock centers, such as the Arabidopsis Biological Resource Center. An accession of Arabidopsis results from adaptations to local environmental conditions, resulting in variation in phenotype and genotype within the species. A lot of what we know about Arabidopsis biology has been limited to just one accession called Columbia-0 (Col-0). Col-0 has proven to be an excellent model to help us better understand plant development, physiology, and responses to biotic and abiotic factors. However, there is considerable intraspecific variation within the Arabidopsis pangenome across accessions. This is in part due to its wide distribution as highlighted by the 1001 Genomes Consortium Project, where they sequenced 1135 Arabidopsis accession genomes. This project overall revealed a global pattern of polymorphism within the species. This variability within the species made me question whether what we know to be true for Col-0 applies to all accessions of this species. For example, we know that the accession Cvi-0 from the Cape Verde Islands is a better stress tolerator. Further, this begs the question, “Can researchers leverage the natural variation in Arabidopsis to learn even more about how plants are responding to the world around them?” The answer is broadly, yes!

A number of studies have already utilized techniques such as quantitative trait loci (QTL) mapping and genome wide association studies (GWAS) to harness natural variation in Arabidopsis. These studies have revealed various genes that are involved in a broad spectrum of processes such as flowering, immunity, growth, and development. By taking a natural variation approach, we can have a better understanding of how distinct phenotypes arise due to natural ecosystems, providing a way to determine the genetic basis of adaptation.

When designing your next study, think about how you can incorporate natural variation to answer your most-pressing questions in plant biology!

Suggested readings and references:

Alonso-Blanco, C., Aarts, M. G., Bentsink, L., Keurentjes, J. J., Reymond, M., Vreugdenhil, D., & Koornneef, M. (2009).What has natural variation taught us about plant development, physiology, and adaptation?. The Plant Cell, 21(7), 1877-1896.

Alonso-Blanco, C., Andrade, J., Becker, C., Bemm, F., Bergelson, J., Borgwardt, K. M., ... & Zhou, X. (2016). 1,135 genomes reveal the global pattern of polymorphism in Arabidopsis thaliana. Cell, 166(2), 481-491.

Somssich, M. (2019). A short history of Arabidopsis thaliana (L.) Heynh. Columbia-0 (No. e26931v5). PeerJ Preprints.

Wójtowicz, J., & Gieczewska, K. B. (2021). The arabidopsis accessions selection is crucial: Insight from photosynthetic studies. International Journal of Molecular Sciences, 22(18), 9866.

Contributed by Christina Rossi

PhD Candidate

Castroverde Lab

Wilfred Laurier University