关键词: Ghuhrf1基因, 启动子, 缺失分析, 克隆, 顺式作用元件

Abstract: The absence of excellent gene and promoter is one of the main factors to restrict the development of genetic engineering in cotton fiber improvement. By analyzing the differential expression profiles in transcriptome databases, it was found that Ghuhrf1 was the dominant expressed at 0 DPA (days post anthesis) flowering in ovules, so it was speculated to be involved in the synthesis of cotton fibers. The fulllength cDNA of Ghuhrf1 gene was cloned by RACE techniques according EST sequence. Realtime PCR analysis indicated that Ghuhrf1 was significantly expressed at the initial stage of fiber cell differentiation. 1 417 bp sequence of Ghuhrf1 promoter was cloned according to the homologous sequence. There were lots of cis-acting factors and the tissue specific regulation elements, such as GCbox, CAATbox, CATbox, CCGTCCbox and ACGTmotif. Based on the distribution of the regulatory elements, four truncations of Ghuhrf1Pro were obtained and transformed into tobacco and Arabidopsis thaliana through Agrobacterium. The results of GUS histochemical staining indicated that the fulllength promoter Ghuhrf1Pro and the truncations Pro1（-1 180～+226 bp）, Pro2 (-867～+226 bp), and Pro3 (-726～+226 bp) could specifically drive the gus gene to express in the differentiated and vigorous growth sites of the leaf tip and petiole base of the transgenic Arabidopsis thaliana, which indicated the meristem expressionrelated CATbox and CCGTCCbox elements played important roles in Ghuhrf1 promoter. At the same time, the promoter deletion analysis further indicated that the Ghuhrf1 gene might not be directly involved in the synthesis of cotton fiber, but indirectly involved in the regulation of the initiation of cotton fiber primitive cell differentiation. Above results provided reference for understanding Ghuhrf1 and regulatory elements for genetic engineering of cotton fiber quality improvement.