Characterization of the plastid-specific germination and seedling establishment transcriptional programme
Characterization of the plastid-specific germination and seedling establishment transcriptional programme
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DOI：
10.1093/jxb/err322
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发表时间：
2012-01-01
影响因子：
6.9
通讯作者：
Lerbs-Mache, S.
中科院分区：
文献类型：
--
作者：
Demarsy, E.;Buhr, F.;Lerbs-Mache, S.
吸胀后，干种子迅速获得代谢活性，并在细胞核中启动萌发特异性转录程序，诱导许多细胞核编码的转录物编码质体定位蛋白。干种子中存在的去分化质体在子叶中分化成叶绿体，在根和下胚轴中分化成淀粉体，这提出了一个问题，即新植物生命周期的开始是否也以质体转录程序的特定变化为特征。在这里，质体转录组的特点是在吸胀/分层，发芽，和早期幼苗生长。它表明，这三个发展步骤的特点是在转录谱的具体变化，由于三个质体RNA聚合酶的差异活动，并显示质体到一个萌发特定的转录程序的整合。所有三种RNA聚合酶在吸胀期间都是活跃的;也就是说，在黑暗中的4摄氏度。然而，质体编码的RNA聚合酶（PEP）的活性仅限于rrn操纵子。在冷释放后，PEP也通过转录光合作用相关基因来改变特异性。萌发和胚根生长的时期的进一步特征在于显着的反义RNA的生产，减少在绿化过程中，光合作用相关的mRNA积累到最高，但非常不同的稳态水平。在层积和萌发过程中，蛋白质积累并不影响mRNA的积累，这表明质体转录比翻译对有效萌发更重要。
Upon imbibition, dry seeds rapidly gain metabolic activity and the switching on of a germination-specific transcriptional programme in the nucleus goes ahead, with the induction of many nucleus-encoded transcripts coding for plastid-localized proteins. Dedifferentiated plastids present in dry seeds differentiate into chloroplasts in cotyledons and into amyloplasts in the root and in the hypocotyl, raising the question of whether the beginning of a new plant's life cycle is also characterized by specific changes in the plastid transcriptional programme. Here the plastid transcriptome is characterized during imbibition/stratification, germination, and early seedling outgrowth. It is shown that each of these three developmental steps is characterized by specific changes in the transcriptome profile, due to differential activities of the three plastid RNA polymerases and showing the integration of plastids into a germination-specific transcriptional programme. All three RNA polymerases are active during imbibition; that is, at 4 degrees C in darkness. However, activity of plastid-encoded RNA polymerase (PEP) is restricted to the rrn operon. After cold release, PEP changes specificity by also transcribing photosynthesis-related genes. The period of germination and radicle outgrowth is further characterized by remarkable antisense RNA production that diminishes during greening when photosynthesis-related mRNAs accumulate to their highest but to very different steady-state levels. During stratification and germination mRNA accumulation is not paralleled by protein accumulation, indicating that plastid transcription is more important for efficient germination than translation.