Development and diversity of root suckers

forthcoming

Clonal reproduction provides certain seed plants with the opportunity to spawn large numbers of clonal individuals in the absence of fertilization. Root sucker formation is a mechanism by which somatic cells of the root spontaneously change their developmental path and give rise to hundreds of clonal offspring. This trait is understudied owing to the scarcity of systems where genetics and advanced imaging can be employed for in-depth studies. Here, I propose to address this problem by developing a diploid Cardamine species as a powerful experimental system for this purpose. This species reproduces not only sexually, but also asexually via root suckers. How root suckers form and how the plant determines the balance between sexual and asexual reproduction is unknown. Close relatives include Arabidopsis thaliana, the best-characterized plant genetic system, and Cardamine hirsuta, a model system that we developed for comparative studies. Yet, neither of these two species form root suckers. I propose to leverage this difference between closely related species to elucidate, at single-cell level, the molecular genetic basis for root sucker development. To jump-start this work, I have in place a genome assembly, genetic transformation and resources for forward and reverse genetics approaches. I will also take advantage of intra-specific natural variation to identify the genetic basis for root sucker diversity and the basis for trade-offs between sexual and asexual reproduction. Ultimately, I aim to reconstruct the root sucker trait from its constituent genetic elements, and transfer it between species. Overall, I will deliver one of the most advanced studies in complex eukaryotes on the genetic basis for development and diversity of clonality – a key trait with significant effects on life history. I will also produce a wealth of resources for the community to further exploit this novel model system.