Molecular adaptation to salinity fluctuation in tropical intertidal environments of a mangrove tree Sonneratia alba
Molecular adaptation to salinity fluctuation in tropical intertidal environments of a mangrove tree Sonneratia alba
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DOI：
10.1186/s12870-020-02395-3
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发表时间：
2020-04-22
影响因子：
5.3
通讯作者：
Shi Suhua
中科院分区：
文献类型：
--
作者：
Feng Xiao;Xu Shaohua;Shi Suhua
背景红树林已经适应了潮间带--陆地和海洋生态系统之间的交界处。各种研究表明，红树林在生理、生态和基因组水平上的适应性进化。然而，这些研究很少关注转录组图谱对盐适应的基因调控。结果对白海棠在低(淡水)、中(海水盐度的一半)和高盐(海水盐度的一半)条件下的转录进行了测序，并研究了盐适应的潜在转录调控。在叶片组织中，当盐度从淡水增加到中等水平时，%潜在盐度相关基因没有差异表达，但当盐分浓度进一步增加到海水中的水平时，这些基因表达上调或下调，表明这些基因对中等盐分条件有很好的适应能力。我们推测，维持和调节细胞环境动态平衡都是白纹伊蚊重要的适应过程。1)在叶片中上调的基因中，硫代谢以及黄酮和黄酮醇生物合成的KEGG途径显著丰富。它们都参与清除ROS或植物体内渗透相关代谢物的合成和积累。Ii)在上调的转录本中，转录因子编码基因的比例显著增加。在高盐条件下，与耐盐相关的转铁蛋白家族高表达。Iii)一些对盐处理反应上调的基因在氨基酸水平上显示出适应性进化的迹象，可能有助于适应波动的潮间带环境。结论本研究首次从全转录组水平上阐明了盐梯度实验处理对红树林高盐适应的机制。这揭示了一些候选基因(包括盐相关基因、Tf编码基因和PSGs)和主要途径参与了对高盐环境的适应。我们的研究也为未来研究极端环境下的适应性进化提供了有价值的资源。
Background Mangroves have adapted to intertidal zones - the interface between terrestrial and marine ecosystems. Various studies have shown adaptive evolution in mangroves at physiological, ecological, and genomic levels. However, these studies paid little attention to gene regulation of salt adaptation by transcriptome profiles. Results We sequenced the transcriptomes of Sonneratia alba under low (fresh water), medium (half the seawater salinity), and high salt (seawater salinity) conditions and investigated the underlying transcriptional regulation of salt adaptation. In leaf tissue, 64% potential salinity-related genes were not differentially expressed when salinity increased from freshwater to medium levels, but became up- or down-regulated when salt concentrations further increased to levels found in sea water, indicating that these genes are well adapted to the medium saline condition. We inferred that both maintenance and regulation of cellular environmental homeostasis are important adaptive processes in S. alba. i) The sulfur metabolism as well as flavone and flavonol biosynthesis KEGG pathways were significantly enriched among up-regulated genes in leaves. They are both involved in scavenging ROS or synthesis and accumulation of osmosis-related metabolites in plants. ii) There was a significantly increased percentage of transcription factor-encoding genes among up-regulated transcripts. High expressions of salt tolerance-related TF families were found under high salt conditions. iii) Some genes up-regulated in response to salt treatment showed signs of adaptive evolution at the amino acid level and might contribute to adaptation to fluctuating intertidal environments. Conclusions This study first elucidates the mechanism of high-salt adaptation in mangroves at the whole-transcriptome level by salt gradient experimental treatments. It reveals that several candidate genes (including salt-related genes, TF-encoding genes, and PSGs) and major pathways are involved in adaptation to high-salt environments. Our study also provides a valuable resource for future investigation of adaptive evolution in extreme environments.