玉米AGPase胞质型小亚基ZmSSUI基因的克隆及在籽粒发育过程中的表达

Cloning of a Cytosolic Small Subunit of AGPase and its Transcripts in the Developing Kernels of Maize(Zea mays)

利用RT-PCR方法从普通玉米浚单20中克隆出淀粉合成关键酶-腺苷二磷酸葡萄糖焦磷酸化酶（ADP-Glucose Pyrophosphorylase,AGPase）胞质型小亚基（cytosolic small subunit,SSUI）基因的cDNA序列,命名为ZmSSUI（GenBank登录号：GU550073）。序列分析表明,该cDNA序列长度1554 bp,包含一个完整的开放阅读框（2~1 429 bp）,长度为1 428 bp,编码476个氨基酸,克隆基因编码的氨基酸序列与其他植物SSUI氨基酸序列有较高同源性。半定量RT-PCR分析表明,在籽粒发育过程中,ZmSSUI基因的表达呈单峰状变化,与已报道的AGPase酶活性及淀粉积累速率趋势基本一致,推测其在玉米淀粉合成中发挥着重要作用。

A cDNA sequence encoding a cytosolic small subunit gene of AGPase was isolated from maize（Zea mays） by RT-PCR and designated as ZmSSU I（GenBank Accession No.GU550073）.Its length was 1 554 bp,containing an open reading frame（ORF） of 1 428 bp encoding a putative protein of 476 amino acids.Sequence alignment indicated that the putative amino acid sequence of ZmSSU I shared high identities 96%,94%,91% and 89% to Zea mays（AAN39299）,Sorghum bicolor（ABK97531）,Oryza sativa（ACJ86322） and Triticum aestivum（AAF61173）,respectively.The transcription levels of ZmSSU I in maize kernels were analyzed with semi-quantitative RT-PCR method.Results showed that the expression of ZmSSU I in developing kernels had a single-peak curve occurring 30 d after pollination.The results showed that ZmSSU I played an important role in maize starch biosynthesis.