Miyama Masashi, Tada Yuichi
School of Bioscience and Biotechnology, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo, Japan.
Plant Mol Biol. 2008 Sep;68(1-2):119-29. doi: 10.1007/s11103-008-9356-y. Epub 2008 Jun 21.
We investigated the transcriptional response of Burma mangrove (Bruguiera gymnorhiza) to high salinity (salt stress; 500 mM NaCl) and hyperosmotic stress (osmotic stress; 1 M sorbitol) by microarray analysis. ANOVA (P < 0.05) and significant analysis of microarray (SAM; FDR < 5%) revealed that 865 of 11,997 genes showed significant differential expression under salt and osmotic stress. Scatter plot analysis revealed that the expression level of genes changed at 6 h after salt stress treatment, but recovered at 24 h, while the change at 6 h after osmotic stress treatment diverged at 24 h. Hierarchical clustering of the 865 genes showed that expression profiles under salt stress were distinctly different from those under osmotic stress. Comparison of gene ontology (GO) categories of differentially expressed genes under the stress conditions revealed that the adaptation of Burma mangrove to salt stress was accompanied by the up-regulation of genes categorized for "cell communication," "signal transduction," "lipid metabolic process," "photosynthesis," "multicellular organismal development," and "transport," and by down-regulation of genes categorized for "catabolic process." Burma mangrove maintained its leaf water potential and recovered from its photosynthesis rate that declined temporarily under salt stress, but not under osmotic stress. These results demonstrated a fundamental difference between the response to salt and osmotic stress. Ion and sugar content analysis suggested that salt tolerance of Burma mangrove might be attributed to their ability to accumulate high concentrations of Na+ and Cl(-), even under non-stressed conditions; to uptake additional Na+ and Cl(-) for use as osmolytes; and to maintain K+ homeostasis under salt stress.
我们通过微阵列分析研究了缅甸红树（木榄）对高盐度（盐胁迫；500 mM NaCl）和高渗胁迫（渗透胁迫；1 M山梨醇）的转录反应。方差分析（P < 0.05）和微阵列显著性分析（SAM；FDR < 5%）表明，在11,997个基因中，有865个基因在盐胁迫和渗透胁迫下表现出显著差异表达。散点图分析显示，盐胁迫处理后6小时基因表达水平发生变化，但在24小时恢复，而渗透胁迫处理后6小时的变化在24小时出现分歧。对这865个基因的层次聚类表明，盐胁迫下的表达谱与渗透胁迫下的明显不同。对胁迫条件下差异表达基因的基因本体（GO）类别进行比较发现，缅甸红树对盐胁迫的适应伴随着“细胞通讯”、“信号转导”\u3001“脂质代谢过程”\u3001“光合作用”\u3001“多细胞生物体发育”和“运输”等类别基因的上调，以及“分解代谢过程”类别基因的下调。缅甸红树维持其叶片水势，并从盐胁迫下暂时下降的光合速率中恢复，但在渗透胁迫下则不然。这些结果表明了对盐胁迫和渗透胁迫反应的根本差异。离子和糖含量分析表明，缅甸红树的耐盐性可能归因于它们即使在非胁迫条件下也能积累高浓度的Na+和Cl−的能力；摄取额外的Na+和Cl−用作渗透剂；以及在盐胁迫下维持K+稳态的能力。
