Aix Marseille Univ, CEA, CNRS, BIAM, UMR7265, SAVE (Signalisation pour l'Adaptation des Végétaux à leur Environnement), Saint-Paul lez Durance, France.
Agroinnovation International-TIMAC AGRO, Groupe Roullier, Saint-Malo, France.
Nat Plants. 2021 Aug;7(8):1050-1064. doi: 10.1038/s41477-021-00981-3. Epub 2021 Aug 9.
Plants are constantly adapting to ambient fluctuations through spatial and temporal transcriptional responses. Here, we implemented the latest-generation RNA imaging system and combined it with microfluidics to visualize transcriptional regulation in living Arabidopsis plants. This enabled quantitative measurements of the transcriptional activity of single loci in single cells, in real time and under changing environmental conditions. Using phosphate-responsive genes as a model, we found that active genes displayed high transcription initiation rates (one initiation event every ~3 s) and frequently clustered together in endoreplicated cells. We observed gene bursting and large allelic differences in single cells, revealing that at steady state, intrinsic noise dominated extrinsic variations. Moreover, we established that transcriptional repression triggered in roots by phosphate, a crucial macronutrient limiting plant development, occurred with unexpectedly fast kinetics (on the order of minutes) and striking heterogeneity between neighbouring cells. Access to single-cell RNA polymerase II dynamics in live plants will benefit future studies of signalling processes.
植物通过时空转录反应不断适应环境波动。在这里，我们实施了最新一代的 RNA 成像系统，并将其与微流控技术相结合，实时可视化活体拟南芥植物中的转录调控。这使得我们能够在单个细胞中对单个基因座的转录活性进行定量测量，即使在环境条件不断变化的情况下也是如此。使用磷酸盐反应基因作为模型，我们发现活性基因表现出高转录起始率（每 3 秒发生一次起始事件），并且在有丝分裂细胞中经常聚集在一起。我们在单个细胞中观察到基因爆发和大的等位基因差异，表明在稳定状态下，内在噪声主导了外在变化。此外，我们发现，植物发育所必需的关键大量营养素磷酸盐在根中引发的转录抑制作用具有出人意料的快速动力学（在几分钟的范围内），并且相邻细胞之间存在显著的异质性。在活体植物中单细胞 RNA 聚合酶 II 动力学的获取将有助于未来对信号转导过程的研究。
