Institute of Plant Biology, National Taiwan University, Taipei, 106, Taiwan, ROC.
Biotechnol Adv. 2012 Nov-Dec;30(6):1309-17. doi: 10.1016/j.biotechadv.2012.01.022. Epub 2012 Jan 28.
The initial investigation of the nature of the proteins in the tuber of sweet potato (Ipomoea batatas Lam.) revealed a globulin-designated "ipomoein," which was reported by Jones and Gersdorff, (1931). Later, "ipomoein" was renamed "sporamin" and was found to be a major storage protein that accounted for over 80% of the total protein in the tuberous root. To date, sporamin has been studied by a series of biochemical and molecular approaches. The first purification of sporamin into two major fractions, A and B, was successfully completed in 1985. Several characteristics of the protein, such as the diversification of the nucleotide sequences in the gene family, the protein structure, the biological functions of storage, defense, inhibitory activity and ROS scavenging, were identified. In the past decade, sporamin was classified as a Kunitz-type trypsin inhibitor, and its insect-resistance capability has been examined in transgenic tobacco and cauliflower plants, indicating the multiple functions of this protein has evolved to facilitate the growth and development of sweet potato. Sporamin is constitutively expressed in the tuberous root and is not normally expressed in the stem or leaves. However, this protein is expressed systemically in response to wounding and other abiotic stresses. These dual expression patterns at the transcriptional level revealed that the complex regulatory mechanism of sporamin was modulated by environmental stresses. The versatile functions of sporamin make this storage protein a good research model to study molecular evolution, regulatory mechanisms and physiological functions in plants. This review summarizes and discusses recent approaches and future perspectives in agricultural biotechnology.
最初对甘薯（Ipomoea batatas Lam.）块根中蛋白质性质的研究揭示了一种球蛋白，被 Jones 和 Gersdorff（1931 年）报道。后来，“ipomoein”被重新命名为“sporamin”，并被发现是一种主要的储存蛋白，占块根总蛋白的 80%以上。迄今为止，sporamin 已经通过一系列生化和分子方法进行了研究。1985 年首次成功将 sporamin 纯化分为两个主要部分 A 和 B。该蛋白的一些特性，如基因家族中核苷酸序列的多样化、蛋白结构、储存、防御、抑制活性和 ROS 清除的生物学功能等被确定。在过去的十年中，sporamin 被归类为 Kunitz 型胰蛋白酶抑制剂，其在转基因烟草和花椰菜植物中的抗虫能力已经过检验，表明该蛋白的多种功能已经进化，以促进甘薯的生长和发育。Sporamin 在块根中组成型表达，在茎或叶中通常不表达。然而，这种蛋白在受到创伤和其他非生物胁迫时会在全身系统中表达。这些在转录水平上的双重表达模式表明，sporamin 的复杂调控机制受到环境胁迫的调节。Sporamin 的多功能性使这种储存蛋白成为研究植物分子进化、调控机制和生理功能的良好研究模型。本综述总结和讨论了农业生物技术的最新方法和未来展望。
