Although mechanisms that activate organogenesis in plants are well established, much less is known about the subsequent fine-tuning of cell proliferation, which is crucial for creating properly structured and sized organs. Here we show, through analysis of temperature-dependent fasciation (TDF) mutants of Arabidopsis, root redifferentiation defective 1 (rrd1), rrd2, and root initiation defective 4 (rid4), that mitochondrial RNA processing is required for limiting cell division during early lateral root (LR) organogenesis. These mutants formed abnormally broadened (i.e., fasciated) LRs under high-temperature conditions due to extra cell division. All TDF proteins localized to mitochondria, where they were found to participate in RNA processing: RRD1 in mRNA deadenylation, and RRD2 and RID4 in mRNA editing. Further analysis suggested that LR fasciation in the TDF mutants is triggered by reactive oxygen species generation caused by defective mitochondrial respiration. Our findings provide novel clues for the physiological significance of mitochondrial activities in plant organogenesis.

中文翻译：

---

温度依赖性束带突变体提供了线粒体 RNA 加工和侧根形态发生之间的联系

尽管激活植物器官发生的机制已经确立，但对随后的细胞增殖微调知之甚少，这对于创建结构和大小适当的器官至关重要。在这里，我们通过分析拟南芥的温度依赖性束带 (TDF) 突变体、根再分化缺陷 1 (rrd1)、rrd2 和根起始缺陷 4 (rid4)，表明线粒体 RNA 加工是限制早期横向细胞分裂所必需的根（LR）器官发生。由于额外的细胞分裂，这些突变体在高温条件下形成异常加宽（即，着迷的）LR。所有 TDF 蛋白都定位于线粒体，在那里它们被发现参与 RNA 加工：RRD1 参与 mRNA 去腺苷酸化，RRD2 和 RID4 参与 mRNA 编辑。进一步的分析表明，TDF 突变体中的 LR 筋膜化是由线粒体呼吸缺陷引起的活性氧生成触发的。我们的研究结果为植物器官发生中线粒体活动的生理意义提供了新的线索。