萝卜过氧化物酶基因片段的cDNA克隆及花期表达谱分析

通过研究过氧化物酶(POD)活性在心里美萝卜花期的变化以及萝卜POD基因的结构,探讨POD的基因结构和功能之间的关系。测定了萝卜花期 不同时间各个部位中POD活性，用改进的半定量RT-PCR分析了过氧化物酶基因(Rsprx)的表达谱，并通过RT-PCR克隆过氧化物酶基因的cDNA片段。结 果表明，心里美萝卜花期不同器官中的POD活性具有明显的变化，地上部分和地下部分POD活性差异显著，在结荚期的木质部II中达到峰值（17.53± 0.35）×10³ U•g^-1(FW)。不同器官中Rsprx的表达差异明显，花蕾和荚中表达最强。从花蕾和荚中得到4个长度为400 bp左右的cDNA克隆片段，序列 比对结果显示，与棉花的花器官过氧化物酶基因Ghpod具有较高的同源性和结构相似性。因此认为POD与萝卜花期生长发育有一定的关系，且有多种 过氧化物酶基因在该过程中表达。

cDNA Partial Cloning of Peroxidases Genes from Raphanus sativus L. And Their Expression in Floral Stage

In order to explore the relationship between the structure and function of peroxidases,the changes of radish peroxidases(POD)activities were investigated at floral stage and the POD gene structure were also analyzed.Activities of POD in different organs of radish were determined.The expression profile of radish peroxidase genes(Rsprx)were analyzed by modified semi-quantitive RT-PCR,some partial cDNAs of radish peroxidase genes were cloned and sequenced.The results showed that the activities of POD were changed greatly in difterent organs at florescence in the Chinese red radish.POD activities were significantly difference between above-ground and under-ground organs.The peak of the POD activity was (17.53±0.35)×10³ U•g^-1 (FW)in xylemⅡ at producing legumen stage.The expression levels of the Rsprx were higher among different organs of Chinese red radish.There were significant differences in expression of Rsprx in bud and legumen.Four radish peroxidase partial cDNAs about 400 bp were cloned from the bud and legumen,which showed high identity and structure similarity with the flower-specific expressed cotton gene Ghpod by sequence alignment. There are correlation between POD and florescence growth and development of radish,and various peroxidases genes expression during the floral organ development processes of radish.