烟蚜热激蛋白Hsp90基因的克隆及在UV-B胁迫下的表达分析
Cloning and expression of Hsp90 gene from green peach aphid Myzus persicae under UV-B stress

为探讨UV-B胁迫对烟蚜Myzus persicae热激蛋白Hsp90基因表达量的影响，采用RT-PCR与RACE技术克隆了烟蚜热激蛋白Hsp90基因的全长，并对其进行生物信息学分析，利用实时荧光定量PCR技术研究了烟蚜Hsp90基因在不同时长UV-B胁迫下的表达量变化。结果表明，烟蚜Hsp90基因的cDNA全长为2 670 bp，编码728个氨基酸，编码蛋白质的相对分子量为82.6 kD，等电点为4.95，获得的氨基酸序列具有Hsp90蛋白家族的1个签名序列及C末端MEEVD基序，推测其属于胞质型热激蛋白。系统进化树结果显示，烟蚜Hsp90与其它昆虫Hsp90具有很高的相似性。实时荧光定量PCR结果表明，不同时长UV-B胁迫下烟蚜Hsp90均有表达，随着照射时间延长，Hsp90表达量表现为先上升后下降的趋势；与对照相比，照射时间为15、30、60、90和120 min时，Hsp90表达量均显著升高，且在60 min时Hsp90表达量达最大，是对照组的2.05倍。表明Hsp90基因在不同时长UV-B胁迫下差异表达，在烟蚜适应紫外胁迫的分子机制中具有重要作用。
To investigate the influences of UV-B stress on the expression of Hsp90 gene from green peach aphid Myzus persicae, the full-length cDNA of Hsp90 gene was amplified by the reverse transcription PCR (RT-PCR) and rapid amplification of cDNA ends (RACE) methods. The characteristics of Hsp90 gene were analyzed by bioinformatic method, and the expression levels of the M. persicae Hsp90 gene under different UV-B treatments were detected by the real-time quantitative PCR. The results showed that the full-length cDNA of M. persicae Hsp90 gene was 2 670 bp, which encoded 728 amino acids, with a molecular weight of 82.6 kD and a theoretical isoelectric point of 4.95. The deduced amino acid sequence of Hsp90 contained one signature sequence of Hsp90 family and a cytoplasmic character sequence (MEEVD) at C-terminal. Therefore, the Hsp90 protein of M. persicae should belong to cytoplasmic heat shock protein. The phylogenetic tree indicated that the protein sequence shared a high homology with Hsp90 proteins from other insect species. The results of real-time quantitative PCR analyses showed that Hsp90 could be induced by UV-B irradiation. The expression of Hsp90 gene increased firstly and then decreased with increasing treatment time. When the treatment time lasted for 15, 30, 60, 90 and 120 min, the expression of Hsp90 gene were significantly higher than that of the control, reaching a peak at 60 min, which was 2.05 times that of the control. The expression level of M. persicae Hsp90 gene varied at different time points of UV-B stress, and it might play an important role in the response of the pests to UV-B stress.