为了解干旱胁迫下烟草的抗旱机制，采用拟南芥基因芯片检测了PEG渗透胁迫（－1.2 MPa）48 h后烟草叶片中基因表达的变化。在31 182个基因微矩阵点中，有效差异表达（ratio值≥2或≤0.5）的基因为135个，上调50个，下调85个。其中包括一些具有防御功能的上调表达基因如两个普遍胁迫蛋白（USP）和与渗透调节物质海藻糖合成有关的基因ATTPS11及多个参与复制、转录和翻译等过程的基因MAPKK、bZIP、锌指蛋白、组蛋白His1-3、脱水响应DREB转录因子、WRKY转录因子家族、分子伴侣等，MAPKK具最大上调幅度，为3.94倍（序列号为At1g51660）。而参与光合作用的6个PSⅠ的光捕获复合体中lhca3和PSⅡ的光捕获复合体中核编码基因的lcb1、lcb2、lcb5、lcb6、lcb4.2的基因表达下调。还检测到38个未知基因，它们的差异表达可能跟渗透胁迫诱导有关，是我们下一步研究的重点。通过分析这些特异表达基因，揭示出一些潜在的生物学规律，为研究烟草逆境生理学提供了有价值的信息。
Attempt to study the drought resistance defense mechanism in tobacco plant, the changes of gene expression in osmotic stressed tobacco (Nicotiana tabacum L.) leaves were analyzed by cDNA micro-array analysis. RNAs of tobacco leaves with or without (CK) PEG treatment for 48 h under －1.2 MPa were extracted and subjected to analysis of cDNA microarray based on Arabidopsis genomic sequence. There were about 135 differently expressed genes (with ratio values≥2 or ≤0.5) among 31 182 genes set in a microarray plate, in which 50 appeared to be up-regulated and 85 appeared to be down-regulated by osmotic stress. Functional analysis showed that some were defensive genes such as trehalose synthase (ATTPS11) and universal stress protein (USP), and the others were related to replication, transcription, translation and protein folding including bZIP family transcription factors, zinc finger proteins, histone H1-3, DREB1C, the WRKY, molecular chaperones and so on. All genes mentioned above were up-regulated by osmotic stress. Gene of MAPKK (At1g51660), a key player in signal transduction pathway, was up-regulated dramatically by 3.94 times. Among down-regulated genes there were 6 genes of light harvesting complex in photosystem Ⅰ and photosystem Ⅱ, including lhca3, lcb1, lcb2, lcb5, lcb6, and lcb4.2. The gene lcb6 (At1g15820) was most down-regulated by 3.9 times. What’s more, 38 unknown function genes were also detected in the experiment. The functions of those genes in plant osmotic stress response need to be elucidated in the future. By analyzing the differently expressed genes some valuable information underlining plant osmotic stress response were highlighted.
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