Enhanced tolerance to ozone and drought stresses in transgenic tobacco overexpressing dehydroascorbate reductase in cytosol
Enhanced tolerance to ozone and drought stresses in transgenic tobacco overexpressing dehydroascorbate reductase in cytosol
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DOI：
10.1111/j.1399-3054.2006.00624.x
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发表时间：
2006-05-01
影响因子：
6.4
通讯作者：
Tanaka, K
中科院分区：
文献类型：
--
作者：
Eltayeb, AE;Kawano, N;Tanaka, K
抗坏血酸（维生素C）是一种有效的抗氧化剂，能保护植物免受诸如臭氧和干旱等环境胁迫造成的氧化损伤。脱氢抗坏血酸还原酶（DHAR；EC 1.8.5.1）是在抗坏血酸（AsA）再生过程中起作用的两种重要酶之一。为了检验DHAR对氧化应激的保护作用，我们培育了过量表达拟南芥细胞质DHAR基因的转基因烟草植株。通过聚合酶链反应和Southern杂交分析证实了转基因整合到烟草植株的基因组中，通过Northern杂交和Western杂交分析证实了其表达。与未转化的对照植株相比，这些转基因植株的DHAR活性提高了2.3 - 3.1倍，还原型AsA水平提高了1.9 - 2.1倍。转基因植株保持了AsA的氧化还原状态，并且在净光合作用较高方面表现出对臭氧、干旱、盐和聚乙二醇胁迫更强的耐受性。在这项研究中，我们首次报道通过靶向细胞质中DHAR的过量表达来提高AsA水平，能显著增强植物对干旱和盐胁迫的氧化应激耐受性。
Ascorbate (vitamin C) is a potent antioxidant protecting plants against oxidative damage imposed by environmental stresses such as ozone and drought. Dehydroascorbate reductase (DHAR; EC 1.8.5.1) is one of the two important enzymes functioning in the regeneration of ascorbate (AsA). To examine the protective role of DHAR against oxidative stress, we developed transgenic tobacco plants overexpressing cytosolic DHAR gene from Arabidopsis thaliana. Incorporation of the transgene in the genome of tobacco plants was confirmed by polymerase chain reaction and Southern blot analysis, and its expression was confirmed by Northern and Western blot analyses. These transgenic plants exhibited 2.3-3.1 folds higher DHAR activity and 1.9-2.1 folds higher level of reduced AsA compared with non-transformed control plants. The transgenic plants showed maintained redox status of AsA and exhibited an enhanced tolerance to ozone, drought, salt, and polyethylene glycol stresses in terms of higher net photosynthesis. In this study, we report for the first time that the elevation of AsA level by targeting DHAR overexpression in cytosol properly provides a significantly enhanced oxidative stress tolerance imposed by drought and salt.