Transgenic salt-tolerant sugar beet (Beta vulgaris L.) constitutively expressing an Arabidopsis thaliana vacuolar Na+/H+ antiporter gene, AtNHX3, accumulates more soluble sugar but less salt in storage roots
Transgenic salt-tolerant sugar beet (Beta vulgaris L.) constitutively expressing an Arabidopsis thaliana vacuolar Na+/H+ antiporter gene, AtNHX3, accumulates more soluble sugar but less salt in storage roots
复制标题
转基因耐盐甜菜 (Beta vulgaris L.) 组成型表达拟南芥液泡 Na /H 逆向转运蛋白基因 AtNHX3，在贮藏根中积累更多可溶性糖，但积累更少盐
DOI：
10.1111/j.1365-3040.2008.01838.x
复制
发表时间：
2008-09-01
影响因子：
7.3
通讯作者：
Zhang, Hongxia
中科院分区：
文献类型：
--
作者：
Liu, Hua;Wang, Qiuqing;Zhang, Hongxia
在拟南芥中，鉴定出了 6 个液泡 Na+/H+ 逆向转运蛋白 (AtNHX1-6)。其中，AtNHX1、2和5是功能性Na+/H+逆向转运蛋白，在幼苗芽和根中表达量最丰富。然而AtNHX3在拟南芥中的表达只能通过RT-PCR检测，其生理功能仍不清楚。在这项工作中，我们证明 AtNHX3 在甜菜 (Beta vulgaris L.) 中的组成型表达赋予转基因植物增强的高盐抗性。在 300 或 500 mM NaCl 存在下，转基因植物在根和贮藏根中显示出非常高的钾积累。此外，转基因植物中保留了蔗糖磷酸合酶（SPS）、蔗糖合酶（SS）和细胞壁蔗糖转化酶（SI）基因的转录本。高盐胁迫条件下生长的转基因植物贮藏根中可溶性糖的积累也较高。我们的结果表明，AtNHX3 也是一种功能性反向转运蛋白，通过介导高等植物中的 K+/H+ 交换来负责耐盐性。盐胁迫条件下，叶片中盐积累但贮藏根中不积累，以及可溶性糖成分含量增加的贮藏根产量增加，表明该基因在提高作物品质和产量方面具有巨大的潜在用途。
In Arabidopsis thaliana, six vacuolar Na+/H+ antiporters (AtNHX1-6) were identified. Among them, AtNHX1, 2 and 5 are functional Na+/H+ antiporters with the most abundant expression levels in seedling shoots and roots. However, the expression of AtNHX3 in Arabidopsis can only be detected by RT-PCR, and its physiological function still remains unclear. In this work, we demonstrate that constitutive expression of AtNHX3 in sugar beet (Beta vulgaris L.) conferred augmented resistance to high salinity on transgenic plants. In the presence of 300 or 500 mM NaCl, transgenic plants showed very high potassium accumulation in the roots and storage roots. Furthermore, the transcripts of sucrose phosphate synthase (SPS), sucrose synthase (SS) and cell wall sucrose invertase (SI) genes were maintained in transgenic plants. The accumulation of soluble sugar in the storage roots of transgenic plants grown under high salt stress condition was also higher. Our results implicate that AtNHX3 is also a functional antiporter responsible for salt tolerance by mediating K+/H+ exchange in higher plants. The salt accumulation in leaves but not in the storage roots, and the increased yield of storage roots with enhanced constituent soluble sugar contents under salt stress condition demonstrate a great potential use of this gene in improving the quality and yield of crop plants.