Single - nucleus transcriptomics uncovers the spatiotemporal development of roots and a histone deacetylase 2B - centered regulatory network in Tartary buckwheat.

Tartary buckwheat (Fagopyrum tataricum) is a nutrient-rich plant valued for its medicinal and dietary applications that accumulates high levels of cellular metabolites. The root system demonstrates potent antioxidant properties. In this study, a single-nucleus resolution transcriptomic atlas of the Tartary buckwheat root system was generated using fluorescence-activated nuclei sorting. The analysis identified 10 major cell types and 22 cell clusters involved in root development, along with newly defined marker genes. The developmental trajectories of specific root cell types, such as root hairs and cortex cells, were mapped, and the key regulatory networks underlying their development were constructed. The flavonoid biosynthetic pathway of Tartary buckwheat was analyzed at the single-cell level. Furthermore, the core regulatory factor FtHD2B in Tartary buckwheat roots promoted the response of roots to stress by positively regulating the synthesis of flavonoids. This study provides the single-nucleus resolution transcriptomic dataset for the root system of a Polygonaceae plant, offering clues for understanding root cell differentiation and root system development within this family.