Deciphering the impact of age on root stem cell homeostasis and regeneration

Objective

Roots are a plant’s source of support, hydration and nutrition. They originate from stem cells located in apical meristems, making stem cell preservation essential for plant survival. To overcome environmental the threats, plants display a great regenerative capacity. Regeneration is also a bottleneck step in the genetic modification of some of the most relevant crops. Thus, understanding stem cell function and regeneration is crucial for crop improvement in order to feed the growing world population. Most root studies focus on the first week of development. Recent work shows evidence of a juvenile-to-adult transition that remains largely unexplored and suggests that the current knowledge on early stages might not apply later. Root tip regeneration is a powerful model to study stem cell reconstitution; however, despite the negative correlation between shoot regeneration potential and age, it has not been studied in older roots. In contrast, transition to adulthood implies an increase in meristem length, a feature positively associated with regeneration capacity, leaving the question open of whether old roots are more or less competent to regenerate than young roots. Moreover, the molecular mechanisms driving the morphological and physiological changes of maturity, and how they impact regeneration, have yet to be unraveled. This project aims to decipher the impact of age on root stem cell homeostasis and regeneration at cellular and molecular level. To this end, I propose to: 1) compare regeneration performance in young and adult roots; 2) record single-cell transcriptional profiles of ageing and regenerating roots; and 3) identify and validate age and regeneration regulators. Combining my expertise on regeneration assays and genetics with the host’s facilities to perform single-cell sequencing, we will advance the understanding of root ageing and regeneration, laying the grounds for future biotechnological applications in plant transformation and crop improvement.