School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China.
Plant Physiol Biochem. 2013 May;66:10-9. doi: 10.1016/j.plaphy.2013.01.021. Epub 2013 Feb 21.
To identify the miRNAs associated with the simulated microgravity response in plants and to ascertain the regulation network mediated by miRNAs under simulated microgravity conditions, we constructed a miRNA library by direct cloning method and analyzed the library. Seven miRNAs that are conserved in other plants were cloned for the first time in Solanum lycopersicum under simulated microgravity condition. The expressions of six of the seven miRNAs were up-regulated, especially by long-term simulated microgravity. Gene ontology analysis showed that most of the predicted targeted genes were involved in transcription regulation, signal transduction and stress response, implying a complicated relationship among the external signal, internal transduction and final phenotype. Six of the predicted targets were validated by 5' RACE and reverse transcription real-time quantitative PCR. The results showed that with increasing miRNA expression levels, the corresponding target genes were down-regulated. The target gene of one of miRNAs, miR159e*, was thought to be associated with an increasing of starch amount under microgravity condition. A multi-stresses response network mediated by miRNAs under simulated microgravity condition was proposed. Cis-elements located in the upstream sequences of each miRNA were identified and their roles in gene regulation were investigated. In addition to the seven miRNAs that had homologs in other plants, six conserved S. lycopersicum miRNAs were identified. In the study, miRNAs were identified in S. lycopersicum for the first time under long-term simulated microgravity condition, which will help reveal the regulation mechanism mediated by miRNAs under simulated microgravity condition and adaptation to Earth's gravity.
为了鉴定与植物模拟微重力反应相关的 miRNA，并确定模拟微重力条件下 miRNA 介导的调控网络，我们采用直接克隆法构建了 miRNA 文库，并对文库进行了分析。首次在模拟微重力条件下从番茄中克隆到 7 个在其他植物中保守的 miRNA。其中 6 个 miRNA 在长期模拟微重力条件下表达上调，特别是在长期模拟微重力条件下。GO 分析表明，大多数预测的靶基因参与转录调控、信号转导和应激反应，表明外部信号、内部转导和最终表型之间存在复杂的关系。其中 6 个预测靶基因通过 5'RACE 和反转录实时定量 PCR 得到验证。结果表明，随着 miRNA 表达水平的升高，相应的靶基因表达水平降低。其中一个 miRNA（miR159e*）的靶基因被认为与微重力条件下淀粉含量的增加有关。提出了一个模拟微重力条件下由 miRNA 介导的多应激反应网络。鉴定了每个 miRNA 上游序列中的顺式元件，并研究了它们在基因调控中的作用。除了在其他植物中具有同源物的 7 个 miRNA 外，还鉴定了 6 个保守的番茄 miRNA。本研究首次在长期模拟微重力条件下鉴定了番茄中的 miRNA，这将有助于揭示模拟微重力条件下 miRNA 介导的调控机制及其对地球重力的适应。
