Link to paper: https://doi.org/10.1002/ajb2.1693
Published: 26 May 2023, The Plant Journal
Plant embryogenic calli (ECs) can undergo somatic embryogenesis to regenerate plants. This process ismediated by regulatory factors, such as transcription factors and specifically expressed genes, but the pre-cise molecular mechanisms underlying somatic embryogenesis at the single-cell level remain unclear. In thisstudy, we performed high-resolution single-cell RNA sequencing analysis to determine the cellular changesin the EC of the woody plant speciesDimocarpus longan(longan) and clarify the continuous cell differentia-tion trajectories at the transcriptome level. The highly heterogeneous cells in the EC were divided into 12putative clusters (e.g., proliferating, meristematic, vascular, and epidermal cell clusters). We determinedcluster-enriched expression marker genes and found that overexpression of the epidermal cell marker geneGDSL ESTERASE/LIPASE-1inhibited the hydrolysis of triacylglycerol. In addition, the stability of autophagywas critical for the somatic embryogenesis of longan. The pseudo-timeline analysis elucidated the continu-ous cell differentiation trajectories from early embryonic cell division to vascular and epidermal cell differen-tiation during the somatic embryogenesis of longan. Moreover, key transcriptional regulators associatedwith cell fates were revealed. We found thatETHYLENE RESPONSIVE FACTOR 6was characterized as aheat-sensitive factor that negatively regulates longan somatic embryogenesis under high-temperaturestress conditions. The results of this study provide new spatiotemporal insights into cell division and differ-entiation during longan somatic embryogenesis at single-cell resolution.