Suppressed expression of the apoplastic ascorbate oxidase gene increases salt tolerance in tobacco and Arabidopsis plants.
Suppressed expression of the apoplastic ascorbate oxidase gene increases salt tolerance in tobacco and Arabidopsis plants.
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DOI：
10.1093/jxb/eri167
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发表时间：
2005-07
影响因子：
6.9
通讯作者：
A. Yamamoto;Md Nazmul H Bhuiyan;Rungaroon Waditee;Yoshito Tanaka;M. Esaka;K. Ôba;A. Jagendorf;T. Tak
中科院分区：
文献类型：
--
作者：
A. Yamamoto;Md Nazmul H Bhuiyan;Rungaroon Waditee;Yoshito Tanaka;M. Esaka;K. Ôba;A. Jagendorf;T. Tak
以有义和反义方向表达抗坏血酸氧化酶 (AAO) 基因的转基因烟草植物，以及将 T-DNA 插入假定的 AAO 基因的拟南芥突变体，用于检查 AAO 在植物耐盐胁迫方面的潜在作用。以有义和反义方向表达该基因的转基因烟草植物中的AAO活性分别是野生型的约16倍和0.2倍。在正常生长条件下，除了反义植物开花时间延迟外，没有观察到表型的显着差异。然而，在高盐度下，反义植物的发芽率、光合活性和种子产量较高，而野生型和有义植物的水平逐渐降低。即使在正常生长条件下，有义植物中质外体抗坏血酸的氧化还原状态也非常低。在盐胁迫下，三类植物中共质体和质外体抗坏血酸的氧化还原状态降低，但在有义植物中最低。有义植物共质体和质外体空间中的过氧化氢含量较高，野生型植物逐渐降低，反义植物次之。拟南芥T-DNA插入突变体表现出非常低的抗坏血酸氧化酶活性，其表型与反义烟草植物相似。这些结果表明，在盐胁迫条件下，质外体 AAO 的表达受到抑制，导致过氧化氢积累水平相对较低，共质体和质外体抗坏血酸处于高氧化还原状态，这反过来又允许更高的种子产量。
Transgenic tobacco plants expressing the ascorbate oxidase (AAO) gene in sense and antisense orientations, and an Arabidopsis mutant in which the T-DNA was inserted into a putative AAO gene, were used to examine the potential roles of AAO for salt-stress tolerance in plants. AAO activities in the transgenic tobacco plants expressing the gene in sense and antisense orientations were, respectively, about 16-fold and 0.2-fold of those in the wild type. Under normal growth conditions, no significant differences in phenotypes were observed, except for a delay in flowering time in the antisense plants. However, at high salinity, the percentage germination, photosynthetic activity, and seed yields were higher in antisense plants, with progressively lower levels in the wild type and the sense plants. The redox state of apoplastic ascorbate in sense plants was very low even under normal growth conditions. Upon salt stress, the redox state of symplastic and apoplastic ascorbate decreased among the three types of plants, but was lowest in the sense plants. The hydrogen peroxide contents in the symplastic and apoplastic spaces were higher in sense plants, progressively lower in the wild type, followed by the antisense plants. The Arabidopsis T-DNA inserted mutant exhibited very low ascorbate oxidase activity, and its phenotype was similar to that of antisense tobacco plants. These results suggest that the suppressed expression of apoplastic AAO under salt-stress conditions leads to a relatively low level of hydrogen peroxide accumulation and a high redox state of symplastic and apoplastic ascorbate which, in turn, permits a higher seed yield.