A soil-grown wheat root atlas with validated cross-species cluster annotations allows to delineate conserved tissue specific marker genes [Spatial Transcriptomics]
Despite the broad use of single-cell and single-nucleus RNA sequencing in plant research, accurate cluster annotation in less studied plant species remains a major challenge due to the lack of validated marker genes. Here, using soil-grown wheat roots as a model, we generated a single-cell RNA-sequencing (scRNA-seq) atlas and annotated cluster identities in an unbiased way by transferring existing annotations from publicly available datasets in wheat, rice, maize and Arabidopsis. These cross-species orthology-based predictions were next validated using untargeted spatial transcriptomics. This information refined existing cluster annotations for different datasets across key plant model species. We then used the validated clusters to generate cell type-specific gene regulatory networks for root tissues of wheat and two other monocot crop species. By integrating all available data, including homeolog expression in wheat, we predicted reliable tissue-specific markers which are conserved across different species. In summary, we provided an annotated and validated single cell transcriptomic resource for soil-grown wheat root apical meristems and revealed conserved cell type-specific regulators and markers across species. These data expand upon previous root single cell atlas resources in crops, and will facilitate cell type annotation in non-model plant species in the future. Overall design: Stereo-seq profiling was performed on a root cap region and regions more distal in soil-grown wheat roots.