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转化是用来描述烟草合成和贮藏尼古丁过程的术语,尼古丁是烟草中存在的主要生物碱形式,在叶片衰老和烘烤过程中,尼古丁的很大比例转化成N去甲基化合物—去甲基烟碱,转化是一种显性性状,且具有不可逆转的特性,能使植物积累去甲基烟碱达到总烟碱量的90%。转化是白肋烟的一个特殊问题,有些品种世代间转化率可高达20%。去甲基烟碱是N’亚硝基去甲基烟碱(NNN)的前体物,N’亚硝基去甲基烟碱(NNN)属于烟草特有亚硝胺,就烟草而言,科学家对降低去甲基烟碱的合成方面的研究有很大的兴趣。对控制转化过程基因的了解,有助于形成新的排除白肋烟中去甲基烟碱的对策,并能从分子水平上理解去甲基烟碱的生成。新的强大的基因组技术将加快农艺学重要基因的鉴定和特性描述。为鉴定转化过程的基因资源,我们利用来源于烟草衰老叶片转化特性的等位基因的cDNA文库构建了一个表达序列标签(EST)数据库,EST数据库基因微阵表达分布,提供了鉴定尼古丁转化基因的新的机会。
Transformation is a term used to describe the process by which tobacco synthesizes and stores nicotine, the major alkaloid present in tobacco. During leaf senescence and toasting, a large proportion of nicotine is converted to N-methyl-demethylated Nicotine, a dominant trait, has irreversible properties that allow plants to accumulate demethyl nicotine up to 90% of the total nicotine content. Transformation is a particular issue with burley tobacco, with conversion rates up to 20% for some varieties over generations. N-methyl nicotine is a precursor of N’-nitroso-n-methyl nicotine (NNN), which is a tobacco-specific nitrosamine and, in the case of tobacco, scientists There is great interest in reducing the synthesis of demethyl nicotine. Knowledge of the genes involved in controlling the transformation helps to create new strategies to eliminate demethyl nicotine in burley tobacco and to understand the generation of demethyl nicotine at the molecular level. The new powerful genomic technology will speed up the identification of agronomic important genes and characterization. To identify the genetic resources involved in the transformation process, we constructed a database of expressed sequence tags (ESTs) using a cDNA library of alleles derived from the transformation characteristics of tobacco senescent leaves. The EST database was genetically microarrayally expressed and provided a platform for identifying nicotine-transformed genes New opportunity