Overexpression of IbP5CR enhances salt tolerance in transgenic sweetpotato
Overexpression of IbP5CR enhances salt tolerance in transgenic sweetpotato
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IbP5CR 过表达增强转基因甘薯的耐盐性
DOI：
10.1007/s11240-013-0415-y
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发表时间：
2014-04-01
影响因子：
3
通讯作者：
Liu, Qingchang
中科院分区：
文献类型：
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作者：
Liu, Degao;He, Shaozhen;Liu, Qingchang
吡咯啉-5-羧酸还原酶（P5 CR）位于谷氨酸和鸟氨酸途径的交汇点，是脯氨酸生物合成的最后和关键酶。本研究从耐盐甘薯品系ND 98中克隆了一个P5 CR基因，命名为IbP 5CR。盐胁迫下甘薯IbP 5CR基因表达上调。将IbP 5CR过表达甘薯（cv. Kokei No. 14）植株与野生型相比表现出显著更高的耐盐性。转基因植株的脯氨酸含量、超氧化物歧化酶活性和光合活性显著提高，而丙二醛含量显著降低。还发现H2 O2在转基因植物中的积累显著低于野生型。在盐胁迫下，IbP 5CR的过表达上调了吡咯啉-5-羧酸合成酶基因，下调了脯氨酸脱氢酶和P5 C脱氢酶基因。盐胁迫下，转基因植株体内活性氧清除基因表达上调。这些结果表明，IbP 5CR基因的过表达增加了脯氨酸的积累，从而通过调节渗透压平衡、保护膜完整性和光合作用以及激活ROS清除系统来增强转基因甘薯的耐盐性。本研究表明IbP 5CR基因具有提高植物耐盐性的潜力。
Pyrroline-5-carboxylate reductase (P5CR) lies at the converging point of the glutamate and ornithine pathways and is the last and critical enzyme in proline biosynthesis. In the present study, a P5CR gene, named IbP5CR, was isolated from salt-tolerant sweetpotato line ND98. Expression of IbP5CR was up-regulated in sweetpotato under salt stress. The IbP5CR-overexpressing sweetpotato (cv. Kokei No. 14) plants exhibited significantly higher salt tolerance compared with the wild-type. Proline content and superoxide dismutase and photosynthetic activities were significantly increased, whereas malonaldehyde content was significantly decreased in the transgenic plants. H2O2 was also found to be significantly less accumulated in the transgenic plants than in the wild-type. Overexpression of IbP5CR up-regulated pyrroline-5-carboxylate synthase gene and down-regulated proline dehydrogenase and P5C dehydrogenase genes under salt stress. The systemic up-regulation of reactive oxygen species (ROS) scavenging genes was found in the transgenic plants under salt stress. These findings suggest that overexpression of IbP5CR increases proline accumulation, which enhances salt tolerance of the transgenic sweetpotato plants by regulating osmotic balance, protecting membrane integrity and photosynthesis and activating ROS scavenging system. This study indicates that IbP5CR gene has the potential to be used for improving salt tolerance of plants.