Abstract: Inorganic pyrophosphatase hydrolyzes inorganic pyrophosphate (PPi) to two ions of phosphate radical (Pi) in vivo. The timely degradation of PPi has been recognized as a key ratelimiting step in the process of disaccharide synthesis, especially sucrose. However, maintaining certain concentration of PPi in vascular bundle cells is required for the translocation of sucrose. Therefore, it could be the best resolution to overexpress inorganic pyrophosphatase gene only in mesophyll tissue, which would feed back and accelerate photosynthesis and produce more carbohydrate. In this research, we firstly analyzed 30 inorganic pyrophosphatase genes predicted in rice by a series of bioinformatics softwares, such as protein clusters, amino acids sequence alignment, protein subcellular localization prediction and ciselements analysis. Secondly, one gene (Os04g0687100) that was considered encoding soluble cytoplasmic inorganic pyrophosphatase, named as OsIP1, was cloned and placed under the rice mesophyllspecific promoter  cyFBPase  from a cytosolic fructose1,6bisphosphatase gene. Thirdly, we transformed this chimeric gene, cyFBPase:OsIP1, into two different  sourcesink type rice varieties using Agrobacteriummediated method, and obtained a total of 48 independent positive transgenic plants.

Key words: rice, inorganic pyrophosphatase, gene cloning, mesophyllspecific promoter

摘要： 无机焦磷酸化酶在植物体内催化焦磷酸基团分解为磷酸基团的反应，而焦磷酸的及时降解，被认为是原初光合产物合成双糖特别是蔗糖，进而进行长距离运输的关键步骤之一。但是，蔗糖在维管束中的运输需要焦磷酸，因此，在叶肉细胞中特异性过表达焦磷酸化酶基因，被认为是拉动和促进光合作用的关键措施之一。对水稻中约30个无机焦磷酸化酶编码基因进行氨基酸序列比较、结构域特征、亚细胞定位预测以及上游顺式元件释义等生物信息学分析，进而克隆了1个预测为编码胞质型可溶性无机焦磷酸化酶的基因OsIP1（Os04g0687100），并将其与叶肉细胞特异性启动子cyFBPase相连，构建成嵌合基因cyFBPase:OsIP1；通过农杆菌转化法将其转入2个水稻品种中，累计获得48个阳性转基因植株。

关键词: 水稻, 无机焦磷酸化酶, 基因克隆, 叶肉细胞特异启动子