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Abstract
背景回顾：The acquisition of pluripotent callus from somatic cells plays an important role in plant development studies and the genetic improvement of crops. This developmental process incorporates a series of cell fate transitions and reprogramming.
提出问题：However, our knowledge of cell heterogeneity and of the mechanisms of cell fate transition during callus induction remains quite limited.
主要发现：Here, we performed a time series single-cell transcriptome experiment on Arabidopsis root explants that were induced in callus induction medium for 0 days, 1 day, and 4 days, and we constructed a detailed single-cell transcriptional atlas of the callus induction process.
结果：We identified the cell types responsible for initiating the early callus: lateral root primordia-initiating (LRPI)-like cells and quiescent center (QC)-like cells. LRPI-like cells are derived from xylem pole pericycle cells and are similar to lateral root primordia. We delineate the developmental trajectory of the dedifferentiation of LRPI-like cells into QC-like cells. QC-like cells are undifferentiated pluripotent acquired cells that appear in the early stages of callus formation and play a critical role in later callus development and organ regeneration. We further inferred the transcription factors that regulating QC-like cells and the gene expression signatures that are related to cell fate decisions.
结论：Overall, our cell-lineage transcriptome atlas for callus induction provides a distinct perspective on cell fate transition during callus formation, and significantly improves understanding of callus formation.
摘 要
由体细胞到多能性愈伤的获取在植物发育研究和作物遗传改良中都发挥重要作用。这一发育过程整合了一系列的细胞命运转变和重编程。但是，我们对于愈伤诱导过程中的细胞异质性和细胞命运转变的机制仍不清楚。本文中，作者以拟南芥的根为外植体，通过对愈伤诱导第0、1和4天的材料进行时间序列单细胞转录组测序，构建了一个详细的愈伤诱导单细胞转录图谱。作者鉴定了一些与愈伤早期起始相关的细胞类型，包括类侧根原基起始细胞和类静止中心细胞。类侧根原基起始细胞源自于木质部极中柱鞘细胞，并且与侧生根原基十分类似。作者描述了类侧根原基起始细胞脱分化形成类静止中心细胞的发育轨迹。类静止中心细胞是未分化的多能性细胞，在愈伤形成的早期出现，并且在之后的愈伤发育和器官再生过程中发挥关键作用。作者进一步推断了调控类静止中心细胞的转录因子，以及与细胞命运决定相关的基因表达特征。综上，本文所揭示的愈伤诱导细胞谱系转录图谱为愈伤形成过程中的细胞命运转变提供了一个不同的视野，极大增加了我们对于愈伤形成的理解。
华大生命科学研究院徐讯研究员和夏科科副研究员为本文共同通讯作者，华大生命科学研究院和中国科学院大学联合培养博士生殷瑞莲为本文第一作者。该研究得到了国家重点研发计划（2022YFC3400300）、广东省基因组读写重点实验室（2017B030301011)、深圳市单细胞组学重点实验室（ZDSYS20190902093613831）和广东省基因组数据中心（2021B1212100001）的联合资助。
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