Understanding Cell States and Their Dynamics During Meristem Formation and Differentiation

Abstract

In this seminar, I will present our recent efforts to define and quantify state transitions in plant stem-cell niches (“meristems”) – both during their terminal differentiation and their de novo formation from non-meristematic cells.

First, by analyzing transcriptomic data from hundreds of tomato meristems, we mapped the floral transition at high temporal resolution and uncovered short-lived gene programs acting just before flowering. We further tested the function of these programs, which, surprisingly, have minimal impact on the production of flowers.

Second, we combined live 3D imaging and single-cell RNA sequencing to understand the cellular dynamics leading to meristem formation in callus tissues undergoing reprogramming, as well as during the development of Marchantia polymorpha spores – single-celled and exposed – which we use as a model to quantitatively track morphogenesis prior to meristem emergence. In both models, our analysis revealed transient, novel cell populations with distinct cell-wall characteristics which precede meristem formation. Discovering how meristems form in plants is key to understanding their later differentiation, and may reflect more broadly on our knowledge of how stochastic biological systems converge into the robust formation of stable niches with particular, multipotent characteristics.

References

Epigenetic memory in cancer cells: Single-cell analysis of clonal maintenance of transcriptional and epigenetic states in cancer cells | Nature Genetics

Flowering in tomato: Dissection of floral transition by single-meristem transcriptomes at high temporal resolution | Nature Plants