Instituto de Recursos Naturales y Agrobiología de Salamanca-Consejo Superior de Investigaciones Científicas, 37071 Salamanca, Spain.
Plant Physiol. 2011 Jul;156(3):1439-56. doi: 10.1104/pp.111.177766. Epub 2011 Apr 29.
The early transcriptional defense responses and reactive oxygen species (ROS) production in Arabidopsis (Arabidopsis thaliana) cell suspension culture (ACSC), containing functional chloroplasts, were examined at high light (HL). The transcriptional analysis revealed that most of the ROS markers identified among the 449 transcripts with significant differential expression were transcripts specifically up-regulated by singlet oxygen ((1)O(2)). On the contrary, minimal correlation was established with transcripts specifically up-regulated by superoxide radical or hydrogen peroxide. The transcriptional analysis was supported by fluorescence microscopy experiments. The incubation of ACSC with the (1)O(2) sensor green reagent and 2',7'-dichlorofluorescein diacetate showed that the 30-min-HL-treated cultures emitted fluorescence that corresponded with the production of (1)O(2) but not of hydrogen peroxide. Furthermore, the in vivo photodamage of the D1 protein of photosystem II indicated that the photogeneration of (1)O(2) took place within the photosystem II reaction center. Functional enrichment analyses identified transcripts that are key components of the ROS signaling transduction pathway in plants as well as others encoding transcription factors that regulate both ROS scavenging and water deficit stress. A meta-analysis examining the transcriptional profiles of mutants and hormone treatments in Arabidopsis showed a high correlation between ACSC at HL and the fluorescent mutant family of Arabidopsis, a producer of (1)O(2) in plastids. Intriguingly, a high correlation was also observed with ABA deficient1 and more axillary growth4, two mutants with defects in the biosynthesis pathways of two key (apo)carotenoid-derived plant hormones (i.e. abscisic acid and strigolactones, respectively). ACSC has proven to be a valuable system for studying early transcriptional responses to HL stress.
悬浮培养的拟南芥细胞（含功能叶绿体）在高光条件下的早期转录防御反应和活性氧（ROS）产生进行了研究。转录分析显示，在 449 个差异表达显著的转录本中，大多数 ROS 标记物是由单线态氧（(1)O(2)）特异性上调的转录本。相反，与超氧自由基或过氧化氢特异性上调的转录本相关性最小。荧光显微镜实验支持了转录分析。用（1）O（2）传感器绿试剂和 2'，7'-二氯荧光素二乙酸酯孵育 ACSC 表明，在 30 分钟高光处理的培养物中发出的荧光与（1）O（2）的产生相对应，而不是与过氧化氢的产生相对应。此外，光系统 II 的 D1 蛋白的体内光损伤表明（1）O（2）的光生成发生在光系统 II 反应中心内。功能富集分析确定了作为植物 ROS 信号转导途径关键组成部分的转录本，以及其他编码调节 ROS 清除和水分胁迫的转录因子的转录本。对拟南芥突变体和激素处理的转录谱进行的荟萃分析表明，高光条件下的 ACSC 与拟南芥荧光突变体家族高度相关，后者是质体中（1）O（2）的产生者。有趣的是，还观察到与 ABA 缺陷 1 和更多腋生生长 4 的高度相关性，这两个突变体在两种关键（脱辅基）类胡萝卜素衍生植物激素（即脱落酸和独脚金内酯）的生物合成途径中存在缺陷。ACSC 已被证明是研究高光胁迫下早期转录反应的有价值的系统。
