Overexpression of NtHAL3 genes confers increased levels of proline biosynthesis and the enhancement of salt tolerance in cultured tobacco cells.
Overexpression of NtHAL3 genes confers increased levels of proline biosynthesis and the enhancement of salt tolerance in cultured tobacco cells.
复制标题
DOI：
10.1093/jxb/erh043
复制
发表时间：
2004-02
影响因子：
6.9
通讯作者：
Ikuko Yonamine;Kazuya Yoshida;Keiji Kido;Atsushi Nakagawa;H. Nakayama;A. Shinmyō
中科院分区：
文献类型：
--
作者：
Ikuko Yonamine;Kazuya Yoshida;Keiji Kido;Atsushi Nakagawa;H. Nakayama;A. Shinmyō
酿酒酵母的 Hal3 蛋白抑制 PPZ1 1 型蛋白磷酸酶的活性，并作为耐盐性和细胞周期控制的调节剂。在植物中，已分离出拟南芥中的两个HAL3同源基因AtHAL3a和AtHAL3b，并通过使用转基因植物研究了AtHAL3a的功能。两个 AtHAL3 基因的表达均由盐胁迫诱导。 AtHAL3a 过表达转基因植物表现出改善的盐和山梨醇耐受性。体外研究表明AtHAL3蛋白具有4'-磷酸泛酰半胱氨酸脱羧酶活性。这一结果表明植物HAL3基因的分子功能与酵母HAL3不同。为了更清楚地了解植物 HAL3 基因在耐盐性中的功能，鉴定了来自烟草的三个烟草 HAL3 基因：NtHAL3a、NtHAL3b 和 NtHAL3c。 NtHAL3 基因在所有器官中以及在所检查的所有应激条件下均持续表达。 NtHAL3a 的过度表达改善了培养烟草细胞的盐、渗透和锂耐受性。 NtHAL3 基因可以补充编码辅酶 A 生物合成途径中 4'-磷酸泛酰基-半胱氨酸脱羧酶的大肠杆菌 dfp 基因中的温度敏感突变。过表达 NtHAL3a 的细胞胞内脯氨酸比例增加。综上所述，这些结果表明 NtHAL3 蛋白参与烟草细胞中的辅酶 A 生物合成途径。
The Hal3 protein of Saccharomyces cerevisiae inhibits the activity of PPZ1 type-1 protein phosphatases and functions as a regulator of salt tolerance and cell cycle control. In plants, two HAL3 homologue genes in Arabidopsis thaliana, AtHAL3a and AtHAl3b, have been isolated and the function of AtHAL3a has been investigated through the use of transgenic plants. Expressions of both AtHAL3 genes are induced by salt stress. AtHAL3a overexpressing transgenic plants exhibit improved salt and sorbitol tolerance. In vitro studies have demonstrated that AtHAL3 protein possessed 4'-phosphopantothenoylcysteine decarboxylase activity. This result suggests that the molecular function of plant HAL3 genes is different from that of yeast HAL3. To understand the function of plant HAL3 genes in salt tolerance more clearly, three tobacco HAL3 genes, NtHAL3a, NtHAL3b, and NtHAL3c, from Nicotiana tabacum were identified. NtHAL3 genes were constitutively expressed in all organs and under all conditions of stress examined. Overexpression of NtHAL3a improved salt, osmotic, and lithium tolerance in cultured tobacco cells. NtHAL3 genes could complement the temperature-sensitive mutation in the E. coli dfp gene encoding 4'-phosphopantothenoyl-cysteine decarboxylase in the coenzyme A biosynthetic pathway. Cells overexpressing NtHAL3a had an increased intracellular ratio of proline. Taken together, these results suggest that NtHAL3 proteins are involved in the coenzyme A biosynthetic pathway in tobacco cells.