College of Life Science, Shenzhen University, Shenzhen, China.
DNA Res. 2012 Apr;19(2):195-207. doi: 10.1093/dnares/dss004. Epub 2012 Feb 19.
Semi-mangroves form a group of transitional species between glycophytes and halophytes, and hold unique potential for learning molecular mechanisms underlying plant salt tolerance. Millettia pinnata is a semi-mangrove plant that can survive a wide range of saline conditions in the absence of specialized morphological and physiological traits. By employing the Illumina sequencing platform, we generated ~192 million short reads from four cDNA libraries of M. pinnata and processed them into 108,598 unisequences with a high depth of coverage. The mean length and total length of these unisequences were 606 bp and 65.8 Mb, respectively. A total of 54,596 (50.3%) unisequences were assigned Nr annotations. Functional classification revealed the involvement of unisequences in various biological processes related to metabolism and environmental adaptation. We identified 23,815 candidate salt-responsive genes with significantly differential expression under seawater and freshwater treatments. Based on the reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR analyses, we verified the changes in expression levels for a number of candidate genes. The functional enrichment analyses for the candidate genes showed tissue-specific patterns of transcriptome remodelling upon salt stress in the roots and the leaves. The transcriptome of M. pinnata will provide valuable gene resources for future application in crop improvement. In addition, this study sets a good example for large-scale identification of salt-responsive genes in non-model organisms using the sequencing-based approach.
半红树植物是盐生植物和陆生植物之间的过渡物种群体，对于研究植物耐盐分子机制具有独特的潜力。毛桐是一种半红树植物，在没有特殊形态和生理特征的情况下，可以在广泛的盐度条件下生存。我们采用 Illumina 测序平台，从毛桐的 4 个 cDNA 文库中生成了约 1.92 亿条短读序列，并将其处理成 108598 条具有高覆盖度的 unisequences。这些 unisequences 的平均长度和总长度分别为 606bp 和 65.8Mb。共有 54596 条 unisequences（50.3%）被分配到 Nr 注释中。功能分类揭示了这些 unisequences 参与了与代谢和环境适应相关的各种生物学过程。我们鉴定了 23815 个候选盐响应基因，这些基因在海水和淡水处理下的表达水平存在显著差异。基于反转录-聚合酶链反应（RT-PCR）和实时 PCR 分析，我们验证了一些候选基因表达水平的变化。候选基因的功能富集分析显示，在根和叶中，盐胁迫下的转录组会发生组织特异性的重塑。毛桐的转录组将为未来在作物改良中的应用提供有价值的基因资源。此外，本研究为利用基于测序的方法在非模式生物中大规模鉴定盐响应基因树立了良好的范例。
