小麦组蛋白基因的表达与其耐盐性

【作者】 李健；

【导师】 赵双宜；

【作者基本信息】 山东大学 ， 遗传学， 2008， 硕士

【摘要】 盐胁迫作用造成植物气孔关闭,光合降低,能耗增加,养分离子吸收不平衡,严重地损害植物质膜的正常功能。目前已从许多植物中分离了一些盐胁迫诱导的基因及基因上游序列,研究了其盐胁迫的信号传导途径及分子机理。有些耐盐基因已被成功转入植物中,提高了植物的耐盐性。因H2A,H2B,H3,H4共同构成了真核生物染色体核小体的八聚体,已发现组蛋白具有多种翻译后修饰现象(如甲基化、乙酰化、磷酸化等),表明其在基因转录调控过程中可发挥重要的作用。邱生平等从盐胁迫处理的水稻幼苗组织中分离了一个新的水稻组蛋白H3基因RH3.2A,在高盐和ABA胁迫下的表达,研究发现在水稻根部RH3.2A基因受高盐的强烈诱导,而在叶片RH3.2A基因的表达则不受高盐诱导,此外RH3.2A基因也受外源ABA的诱导,可能参与了依赖于ABA的高盐胁迫应答反应。为了进一步了解山融三号耐盐小麦在盐胁迫条件下的基因表达的规律,本实验提取了普通小麦盐胁迫下组织的总RNA,经反转录荧光标记制备cDNA探针,并将其与小麦基因芯片进行杂交,扫描采集数据后并进行分析。根据芯片杂交结果,小麦在盐胁迫下其组蛋白基因的表达具有共同下调的现象,但不同组蛋白基因的表达程度差异很大,甚至有个别组蛋白基因发生上调。在济南177中,有22条组蛋白在叶中上调而有6条组蛋白在叶中下调,有9条组蛋白在根中上调而有124条组蛋白在根中下调。在山融三号中有5条组蛋白在叶中上调而有122条组蛋白在叶中下调,有37条组蛋白在根中上调而有20条组蛋白在根中下调。为了证实小麦芯片杂交结果的正确性,我们采用了real-time PCR对芯片中表达特异的(5个组蛋白基因)组蛋白进一步分析,结果证明大多数组蛋白基因的表达趋势与芯片结果基本相符。最后,我们选择了其中Ⅰ-H2B基因转入拟南芥中,目前获得了TO代,为进一步的验证在耐盐中的功能奠定基础。更多还原

【Abstract】 Salt stress induces stoma-closing, photosynthesis-decreasing,over energy-consuming and unbalance of inorganic ion absorbing and damages the functions of plasma membrane.Now many salt-inducible genes and upstream sequences have been cloned, and there was certainly progress on Molecular mechanism of plant biotic and abiotic stress signaling. Some salt-inducible genes have been transformed into plants, and it was evidenced that exogenous gene can enforce the ability to tolerate salt stress.The nucleosome consists of an octamer of two copies of the four core histones H2A, H2B, H3 and H4 in eukaryotes;many histone post-translational modifications can serve a distinct function in transcriptonal regulation (e.g.methylation,acetylation,phosp-horylation),and that indicated they could play a key role on the molecular mechanisms of salt-stress tolerance. RH3.2A was cloned through RT-PCR from salt-treated rice seedlings by Qiu Sheng Ping.The mRNA expression analysis of RH3.2A revealed that RH3.2A gene was upregulated by salt stress in rice roots and ABA treatment in seedlings. The potential role of RH3.2A during salt stress was discussed.For investigating the Shan Rong 3 wheat (salt-tolerant wheat) transcriptional profiling salt stress,RNA samples were collected at different hours mixly influence dye-labeled complimentary DNA were used to hybridize with the whole genome wheat gene chip. Data analysis indicated that most of the histone genes was down-regulated simultaneously but interestingly,there were great changes of different expressed histone genes,even individual histone genes were up-regulated. In Jinan 177,22 histone genes were upregulated by salt stress in leaves and 9 histone genes were downregulated by salt stress in leaves; 9 histone genes were upregulated by salt stress in roots and 124 histone genes were downregulated by salt stress in roots.In Shan rong 3,5 histone genes were upregulated by salt stress in leaves and 122 histone genes were downregulated by salt stress in leaves; 37 histone genes were upregulated by salt stress in roots and 20 histone genes were downregulated by salt stress in roots. This were further verified to be true by Real Time PCR. Generally speaking,Real Time PCR analysis indicated that five cloned histone genes expressed the same as gene chip’s data.At last we have chosen one of them named I-H2B to Transform of Arabidopsis.Now,we have TO seeds for investigating its function in plant.更多还原