Ectopic expression of nicotianamine synthase genes results in improved iron accumulation and increased nickel tolerance in transgenic tobacco
Ectopic expression of nicotianamine synthase genes results in improved iron accumulation and increased nickel tolerance in transgenic tobacco
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DOI：
10.1111/j.1365-3040.2005.01273.x
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发表时间：
2005-03-01
影响因子：
7.3
通讯作者：
Bäumlein, H
中科院分区：
文献类型：
--
作者：
Douchkov, D;Gryczka, C;Bäumlein, H
重金属对于基本细胞过程至关重要，但浓度较高时有毒。这需要精确控制它们的细胞内浓度，这一过程称为稳态。金属螯合非蛋白氨基酸烟酰胺 (NA) 是植物金属同化和体内平衡的关键成分。其具体功能尚不清楚。因此，本文旨在提供有关 NA 体内功能的新信息，并评估其在植物营养和作物强化方面的潜在用途。为此目的，拟南芥的烟酰胺合酶基因在转基因烟草植物中异位表达。与野生型相比，烟草胺合酶基因的额外拷贝与 NA 水平共分离高达 10 倍。 NA 水平的增加导致： (a) 成年植物叶子中的铁水平显着增加； (b) 积累锌和锰，但不积累铜； (c)提高在铁限制下生长的成年植物的铁利用效率； (d) 对高达 1 mM 镍的耐受性增强。综上所述，数据预测 NA 可能是改善不良土壤上植物营养的有用工具，并可能提高叶类和种子作物的营养价值。
Heavy metals are essential for basic cellular processes but toxic in higher concentrations. This requires the precise control of their intracellular concentrations, a process known as homeostasis. The metal-chelating, non-proteinogenous amino acid nicotianamine (NA) is a key component of plant metal assimilation and homeostasis. Its precise function is still unknown. Therefore, this article aims to contribute new information on the in vivo function of NA and to evaluate its potential use for plant nutrition and crop fortification. For this purpose, a nicotianamine synthase gene of Arabidopsis thaliana was ectopically expressed in transgenic tobacco plants. The presence of extra copies of the nicotianamine synthase gene co-segregated with up to 10-fold elevated levels of NA in comparison with wild type. The increased NA level led to: (a) a significantly increased iron level in leaves of adult plants; (b) the accumulation of zinc and manganese, but not copper; (c) an improvement of the iron use efficiency in adult plants grown under iron limitation; and (d) an enhanced tolerance against up to 1 mM nickel. Taken together, the data predict that NA may be a useful tool for improved plant nutrition on adverse soils and possibly for enhanced nutritional value of leaf and seed crops.