A High-Resolution Root Spatiotemporal Map Reveals Dominant Expression Patterns

TLDR

Transcriptional programs that regulate development are exquisitely controlled in space and time, and elucidating these programs is essential to understanding cell and tissue identity acquisition. The study presents high‑resolution microarray expression profiles across developmental time points in a single Arabidopsis root and a comprehensive map of nearly all root cell types. The authors used a computational pipeline to identify dominant expression patterns revealing transcriptional similarity between disparate root cell types. The analysis revealed that cell‑type specific transcriptional signatures predict novel cellular functions, dominant expression patterns vary along the root axis independent of traditional developmental zones, robust co‑regulation and phasing occur between individual roots, and combined profiles expose complex, spatially and temporally rich programs governing Arabidopsis root development.

Abstract

Transcriptional programs that regulate development are exquisitely controlled in space and time. Elucidating these programs that underlie development is essential to understanding the acquisition of cell and tissue identity. We present microarray expression profiles of a high-resolution set of developmental time points within a single Arabidopsis root and a comprehensive map of nearly all root cell types. These cell type-specific transcriptional signatures often predict previously unknown cellular functions. A computational pipeline identified dominant expression patterns that demonstrate transcriptional similarity between disparate cell types. Dominant expression patterns along the root's longitudinal axis do not strictly correlate with previously defined developmental zones, and in many cases, we observed expression fluctuation along this axis. Both robust co-regulation of gene expression and potential phasing of gene expression were identified between individual roots. Methods that combine these profiles demonstrate transcriptionally rich and complex programs that define Arabidopsis root development in both space and time.