烟草过氧化氢酶基因CAT1的克隆及表达特征分析

基于GeneBank中已有的植物Catalase 1（CAT1）基因序列设计烟草CAT1的特异性引物，通过RT-PCR扩增克隆获得Nicotiana tabacum var. NC89 CAT1全长mRNA序列，可编码492个氨基酸残基。遗传进化分析显示NC89 CAT1中与N .benthamiana CAT1基因亲缘关系最近。利用real-time RT-PCR技术对CAT1基因在烟草中的组织表达特异性和烟草NC89应对生物和非生物胁迫的表达差异进行了分析。结果表明CAT1基因在烟草NC89的根、茎、叶、花瓣、花萼、种子中均有表达，其中在根部表达量最低，在叶中相对表达量最高。生物和非生物胁迫处理烟株，其CAT1诱导表达分析显示，机械损伤、渗透压、低温和高温、干旱、和感染TMV CAT1表达量上调，紫外胁迫下表达量下调。上述研究表明烟草CAT1基因可能参与了植物的生长发育、应对非生物和生物胁迫的过程。 

Molecular Cloning,Characterization and Expression of Catalase1 Gene of Nicotiana tabacum

The full-length cDNA of Catalse 1 (CAT1) of Nicotiana tabacum var. NC89 was cloned based on the specific primers designed according to CAT1 mRNA sequences of other plants, an amino acide sequence aligment indicated that CAT1 contains 492 amino acides. The phylogenetic analysis showed that NC89 CAT1 shares high similarity with the gene of N.benthamiana. Real-time quantitative polymerase chain reaction (qPCR) analysis revealed that CAT1 is highly expressed in the leaf and calyx, but little expressed in roots and seeds. The expression of NC89 CAT1 was enhanced by abiotic and biotic stressors, such as mechanical damage, osmotic pressure, low temperature, high temperature, drought, and TMV infection, whereas it was inhibited by ultraviolet irradiation. Here, we infer from our result that CAT1 acts an important role in growth, development, and interplay of abiotic and biotic stresses in plant.