背景回顾：H2O2 is recognized as an important signaling molecule in plants. 

主要研究：We sought to establish a genetically encoded, fluorescent H2O2 sensor that allows H2O2 monitoring in all major subcompartments of a Chlamydomonas cell. 

研究方法：To this end, we used the Chlamydomonas Modular Cloning toolbox to target the hypersensitive H2O2 sensor roGFP2-Tsa2ΔCR to the cytosol, nucleus, mitochondrial matrix, chloroplast stroma, thylakoid lumen, and endoplasmic reticulum (ER). 

测试结果：The sensor was functional in all compartments, except for the ER where it was fully oxidized.

应用案例-1：Employing our novel sensors, we show that H2O2 produced by photosynthetic linear electron transport (PET) in the stroma leaks into the cytosol but only reaches other subcellular compartments if produced under non-physiological conditions. 

应用案例-2：Furthermore, in heat-stressed cells, we show that cytosolic H2O2 levels closely mirror temperature up- and downshifts and are independent from PET. Heat stress led to similar up- and downshifts of H2O2 levels in the nucleus and, more mildly, in mitochondria but not in the chloroplast. 

结论：Our results thus suggest the establishment of steep intracellular H2O2 gradients under normal physiological conditions with limited diffusion into other compartments.

展望：We anticipate that these sensors will greatly facilitate future investigations of H2O2 biology in plant cells.

 摘 要 

过氧化氢是植物中一种重要的信号分子。本文中，作者试图建立一个基因编码的过氧化氢荧光传感器，能够监测衣藻细胞亚隔室中的过氧化氢。为此，作者利用衣藻模块化克隆工具将超敏过氧化氢传感器roGFP2-Tsa2ΔCR靶向细胞质、细胞核、线粒体基质、叶绿体基质、类囊体腔和内质网（ER）。除了ER以外，该传感器在所有的细胞隔室中都能正常工作，在ER中其会被完全氧化。利用这种新型传感器，作者发现基质中光合线性电子传递（PET）产生的过氧化氢会泄漏到细胞质中，但如果在非生理条件下产生的过氧化氢，仅传递到其它亚细胞隔室。此外，在热胁迫的细胞中，作者发现细胞内过氧化氢的水平与温度的上升和下降密切相关，并且独立于PET。热胁迫导致细胞核和线粒体中过氧化氢含量出现类似的上升和下降趋势，但叶绿体中的过氧化氢则没有。因此，本文的研究结果表明，在正常生理条件下，细胞内的过氧化氢具有落差较大的浓度梯度，但并很难扩散到其它的细胞隔室。作者认为这些新型传感器将会极大地促进植物细胞中有关过氧化氢生物学的研究。