Evolution of leaf shape diversity in Angiosperms using single cell approaches

Leaves show a large scale of morphological diversity.

Advanced time-lapse imaging and computational analysis revealed specific growth differences underlying development of different leaf forms in the simple leaves of A. thaliana vs the complex leaves of its relative C. hirsuta.

However, this does not capture the differences in genetic networks that underlie these growth changes during development.

To solve this problem, I will apply state-of-the-art single cell technologies to dissect the genetic networks behind leaf development and complexity.

First, by utilizing multimodal single cell sequencing technologies in high temporal resolution, I will describe the cell-type specific gene regulatory networks (GRNs) during leaf development.

By comparing these cell types and GRNs between A. thaliana and C. hirsuta we will be able to make major steps on understanding mechanisms underlying development and diversity of leaf forms.To understand how the newly discovered GRNs interact in a developing tissue context I will apply spatial transcriptomics to understand how local genetic changes can influence morphogenesis.

To analyze this, I will implement a novel functionality in a software, MorhoGraphX, which was originally developed for microscopy-based growth analysis.

This way, it will be possible to directly link the genetic regulators to cellular morphological properties.A selected number of these regulators will be further investigated with comparative genetic methods empowered by gene editing.To further extend the findings and place them into a broader evolutionary perspective, I will investigate cell type specific GRNs in two Solanaceae species, one with simple (pepper) and one with complex leaves (tomato).By comparing the commonalities and differences between simple and complex leaves in Brassicaceae and Solanaceae, which occurred independently during evolution, we can reveal developmental and evolutionary constrains underlying differences between simple and complex leaf.