Cell wall invertase in developing rice caryopsis:: Molecular cloning of OsCIN1 and analysis of its expression in relation to its role in grain filling
Cell wall invertase in developing rice caryopsis:: Molecular cloning of OsCIN1 and analysis of its expression in relation to its role in grain filling
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DOI：
10.1093/pcp/pcf055
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发表时间：
2002-04-01
影响因子：
4.9
通讯作者：
Terao, T
中科院分区：
文献类型：
--
作者：
Hirose, T;Takano, M;Terao, T
为了确定细胞壁转化酶在水稻籽粒灌浆中的作用，我们从发育中的水稻籽粒中克隆了细胞壁转化酶的cDNA。该cDNA被命名为OsC1N1，包含一个1731 bp的开放阅读框，编码577个氨基酸残基的多肽。推导出的氨基酸序列与玉米细胞壁转化酶Incw1和Incw2的同源性分别为78.6和73.7%，具有典型的细胞壁转化酶特征，包括对果糖苷酶基序和半胱氨酸催化位点。OsC1N1在根、汇源叶和穗中表达。在颖果灌浆过程中，OsC1N1转录物仅在颖果发育的早期，即开花后1-4天检测到，此时细胞壁转化酶活性最高，颖果长度增加最快。原位定位结果显示，OsC1N1优先表达于背静脉血管薄壁、被膜及其周围细胞，在珠心突起和珠心表皮表达较弱。这些结果表明，在颖果发育的早期阶段。OsC1N1通过切割外质体中的卸载蔗糖，为发育中的子代组织提供碳源。
To establish the significance of cell wall invertase in grain filling of rice (Oryza sativa L.), we cloned a cDNA for a cell wall invertase from developing grains of rice. The cDNA, designated OsC1N1, contains an open reading frame of 1731 bp encoding a polypeptide of 577 amino acid residues. The deduced amino acid sequence showed typical features of the cell wall invertases, including a P-fructosidase motif and a cysteine catalytic site, and shared 78.6 and 73.7% identity with maize cell wall invertases, Incw1 and Incw2, respectively. OsC1N1 is expressed in roots, in sink-and source-leaves, and in panicles. During the course of grain filling in the caryopses, OsC1N1 transcript is detectable only in the very early stage of their development, 1-4, d after flowrering, when the cell wall invertase activity is the highest and the increase in caryopsis length is rapid. In situ localization of the mRNA revealed that OsC1N1 is expressed preferentially in the vascular parenchyma of the dorsal vein, integument and its surrounding cells, and is expressed weakly in the nucellar projection and nucellar epidermis. These results suggest that, during the early stage of caryopsis development. OsC1N1 is important for supplying a carbon source to developing filial tissues by cleaving unloaded sucrose in the apoplast.