Plant Biotechnology, Department of Biology, ETH Zurich, Universitätstrasse, Zurich, Switzerland.
Biotechnology Center, National Chung Hsing University, Taichung City, Taiwan.
J Exp Bot. 2022 Sep 12;73(16):5440-5459. doi: 10.1093/jxb/erac214.
Intrinsic improvement of iron (Fe) concentration in rice grains, called rice Fe biofortification, is a promising countermeasure against widespread human Fe deficiency. In this study, two novel rice Fe biofortification approaches are reported. The first approach (Y approach) involved the expression of maize YELLOW STRIPE 1 controlled by the HEAVY METAL ATPASE 2 promoter. The Y approach increased the polished grain Fe concentrations up to 4.8-fold compared with the non-transgenic (NT) line. The second approach (T approach) involved the expression of rice TRANSPORTER OF MUGINEIC ACID 1 controlled by the FERRIC REDUCTASE DEFECTIVE LIKE 1 promoter. The T approach increased the polished grain Fe concentrations by up to 3.2-fold. No synergistic increases in the polished grain Fe concentrations were observed when Y and T approaches were combined (YT approach). However, the polished grain Fe concentrations further increased by 5.1- to 9.3-fold compared with the NT line, when YT approach was combined with the endosperm-specific expression of FERRITIN (YTF approach), or when YTF approach was combined with the constitutive expression of NICOTIANAMINE SYNTHASE (YTFN approach). Total grain weight per plant in most Y, T, YT, and YTFN lines was comparable to that in the NT line, while it was significantly decreased in most YTF lines. The novel approaches reported in this study expand the portfolio of genetic engineering strategies that can be used for Fe biofortification in rice.
提高稻米中铁（Fe）浓度的内在改良，即稻米 Fe 生物强化，是应对广泛存在的人类 Fe 缺乏症的一种很有前途的对策。本研究报道了两种新的稻米 Fe 生物强化方法。第一种方法（Y 方法）涉及由 heavy metal ATPase 2 启动子控制的玉米 YELLOW STRIPE 1 的表达。Y 方法使抛光稻米 Fe 浓度比非转基因（NT）系增加了 4.8 倍。第二种方法（T 方法）涉及由 FERRIC REDUCTASE DEFECTIVE LIKE 1 启动子控制的水稻 TRANSPORTER OF MUGINEIC ACID 1 的表达。T 方法使抛光稻米 Fe 浓度增加了 3.2 倍。当 Y 和 T 方法结合（YT 方法）时，没有观察到抛光稻米 Fe 浓度的协同增加。然而，当 YT 方法与胚乳特异性表达 FERRITIN（YTF 方法）结合，或当 YTF 方法与 NICOTIANAMINE SYNTHASE 的组成型表达（YTFN 方法）结合时，与 NT 系相比，抛光稻米 Fe 浓度进一步增加了 5.1-9.3 倍。大多数 Y、T、YT 和 YTFN 系的每株总谷物重量与 NT 系相当，而大多数 YTF 系的总谷物重量显著降低。本研究报道的新方法扩展了遗传工程策略的组合，可以用于稻米 Fe 生物强化。
