scRNA-seq Reveals the Mechanism of Fatty Acid Desaturase 2 Mutation to Repress Leaf Growth in Peanut ( Arachis hypogaea L.).

() controls the conversion of oleic acids into linoleic acids. Mutations in not only increase the high-oleic content, but also repress the leaf growth. However, the mechanism by which regulates the growth pathway has not been elucidated in peanut leaves with single-cell resolution. In this study, we isolated mutant leaf protoplast cells to perform single-cell RNA sequencing. Approximately 24,988 individual cells with 10,249 expressed genes were classified into five major cell types. A comparative analysis of 3495 differentially expressed genes (DEGs) in distinct cell types demonstrated that inhibited the expression of the cytokinin synthesis gene in vascular cells, thereby repressing leaf growth. Further, pseudo-time trajectory analysis indicated that repressed leaf cell differentiation, and cell-cycle evidence displayed that perturbed the normal cell cycle to induce the majority of cells to drop into the S phase. Additionally, important transcription factors were filtered from the DEG profiles that connected the network involved in high-oleic acid accumulation (), activated the hormone pathway (, ), and potentially regulated leaf growth (, , ). Collectively, our study describes different gene atlases in high-oleic and normal peanut seedling leaves, providing novel biological insights to elucidate the molecular mechanism of the high-oleic peanut-associated agronomic trait at the single-cell level.