拟南芥高迁移率族蛋白B族基因表达模式分析

摘要

为了解高迁移率族蛋白B族(HMGB)基因在拟南芥中的表达模式及作用方式,该研究克隆了拟南芥中5个编码HMGB的基因:AtHMGB1、AtHMGB2、AtHMGB3、AtHMGB4、AtHMGB5,并运用荧光实时定量PCR方法检测野生型拟南芥中以上5种基因在不同器官中的表达及在外源植物激素(ABA、2,4-D)处理前后的表达差异,选取AtHMGB2、AtHMGB4和AtHMGB5分别转化拟南芥并筛选出超表达株系,随即检测ABA诱导下超表达AtHMGB的转基因拟南芥的表型.研究证实:在野生型拟南芥中AtHMGB2在拟南芥各个器官中的表达量远高于其它家族成员,AtHMGB4和AtHMGB5在花、果荚和根中的表达略高于茎和叶；在ABA处理前后AtHMGB家族成员的表达水平有显著差异,其中AtHMGB2的表达被ABA显著负调控；ABA诱导下超表达AtHMGB2的转基因拟南芥与野生型相比出现萌发及生长迟缓现象,但超表达AtH MG B4与AtHMGB5的转基因拟南芥在ABA诱导下的种子萌发和幼苗生长与野生型相比差异不大.研究发现,AtHMGB家族成员在转录水平上响应ABA的方式各有不同,对理解AtHMGB家族成员的生物学功能提供了新的基础.%To better understand the expression and function of the High Mobility Group Protein B (HMGB) family genes in Arabidopsis ,we cloned the first five genes encoding HMGB proteins in Arabidopsis thali-ana genome:AfHMGB 1, AtHMGBZ,AtHMGBZ,AtHMGB and AtHMGBb. Real-time reverse transcrip-tion-PCR (RT-PCR) analysis was employed to determine the transcript levels of HMGB genes accurately in Arabidopsis wild-type under plant phytohormone treatment. Binary vectors carrying the AtHMGB2, AtHMGBA and AtHMGB5 genes were transformed into Arabidopsis to detect the phenotype of the trans-genic Arabidopsis induced by ABA. Our results proved that AtHMGB2 was more abundantly expressed than other family members,whereas AtHMGBA and AtHMGB5 were more abundantly expressed in roots and flowers than in stems and leaves. The expression level of the AtHMGB family genes were markedly regulated by ABA induction,especially the AtHMGB2. Under ABA treatment,the transgenic Arabidopsis plants that over-expressed AtHMGB2 displayed retarded germination and subsequent growth compared with the wild-type Arabidopsis. Overexpression of AtHMGBA and AtHMGBb had little impact on seed germination and seedling growth of the plants by ABA induction. Taken together, these results provide anovel basis for understanding the biological functions of AtHMGB family members under ABA conditions.