De Novo Formation of Root Meristems

Plants are able to generate root meristems in multiple developmental contexts. The most common and best described is the initiation of lateral roots which are produced from prepatterned regions of the specialized root pericycle. However, plants can also form root meristems de novo, in a process that is much less understood. This crucial ability for meristem initiation underlies plants remarkable capacity for regeneration.

To study de novo meristem initiation, we introduced the tomato as a new model system. Unlike the commonly used Arabidopsis, tomato naturally initiate root meristems on easily accessible stems, without the need for injury. A genetic screen for tomato plants defective in stem-borne root meristem initiation has identified several novel mutants and their role in the process is being investigated. To profile the very early stages of tomato de novo meristem initiation we employed high resolution and single-cell-level transcriptomics across multiple developmental stages. Cross-species comparative transcriptomics and analysis of hormonal dynamics have allows us to identify components of an evolutionary-conserved common program for meristem formation.