Spatial transcriptome analysis reveals de novo regeneration of poplar roots

Propagation through cuttings is a well-established and effective technique for plant multiplication. This study explores the regeneration of poplar roots using spatial transcriptomics to map a detailed developmental trajectory. Mapping of the time-series transcriptome data revealed notable alterations in gene expression during root development, particularly in the activation of cytokinin-responsive genes. Our analysis identified six distinct clusters during the second and third stages, each corresponding to specific anatomical regions with unique gene expression profiles. Auxin response cis-elements (AuxREs) were prevalent in the promoters of these cytokinin-responsive genes, indicating a regulatory interplay between auxin and cytokinin. Pseudo-temporal trajectory analysis mapped the differentiation from cambium cells to root primordium cells, revealing a complex pattern of cell differentiation. SAC56 and LOS1 emerged as potential novel biomarkers for enhancing root regeneration, with distinct spatial expression patterns confirmed by in situ hybridization. This comprehensive spatial analysis enhances our understanding of the molecular interactions driving root regeneration and provides insights for improving plant propagation techniques.