渗透胁迫下烟草根系基因的表达谱分析

 【目的】了解干旱胁迫下烟草的抗旱机制。【方法】采用拟南芥基因芯片检测PEG渗透胁迫（-1.2 MPa）48 h后烟草根系中基因表达的变化。【结果】在31 182个基因微矩阵点中，有效差异表达（ratio 值≥2或≤0.5）的基因有126个，其中上调79个，下调47个。上调基因主要是根系中一些受渗透胁迫诱导参与信号转导的激素（主要是ABA）响应蛋白基因、钙信号响应蛋白基因及蛋白激酶基因。而下调表达的基因则主要是一些与烟株生长发育相关的赤霉素响应蛋白类基因和根系中参与蛋白质降解的泛素连接酶类基因。【结论】通过分析这些特异表达基因，揭示出烟草植株体在非生物环境胁迫条件下的一些响应机制，为阐明烟草抗旱的分子生物学机理提供了有价值的信息。

Analysis of Gene Expression Profiles in Tobacco Roots Under Osmotic Stress

【Objective】The objective of this experiment is to study the drought resistance defense mechanism in tobacco plant. 【Method】 The changes of gene expression in osmotic stressed tobacco (Nicotiana tabacum L) roots were analyzed by cDNA microarray analysis. RNAs of tobacco roots with or without (CK) PEG treatment after 48 h under -1.2 MPa were extracted and subjected to analysis of cDNA microarray based on Arabidopsis genomic sequence. 【Result】 There were about 126 differently expressed genes (with ratio values ≥2 or ≤0.5) among 31 182 genes set in a microarray plate，in which 79 genes were up-regulated and 47 down-regulated by osmotic stress. Among the up-regulated genes, a lot of them such as ABA responsive protein，calcium signaling responsive protein and protein kinase were found in signaling transduction pathway, suggesting that signaling transduction in roots under osmotic stress was activating. Meanwhile, some hydrolase genes in relation to membrane system and transporter were also up-regulated under osmotic stress. But some genes regulating growth and development of tobacco plant, such as the genes of gibberellin-responsive protein, nitrate reductase 2 (NR2) and so on, were down regulated. Some genes of E3 ubiquitin ligase, the key components in ubiquitin-mediated protein degradation pathway, were also down regulated. Moreover, 58 unknown function genes were also detected in the experiment. The functions of those genes in plant osmotic stress response needed to be elucidated in the future. 【Conclusion】 By analyzing the differently expressed genes, some valuable information for explaining the molecular mechanism of drought-resistance of tobacco plant were highlighted.