对付缺铁：含铁量是精白米粒六倍多的稻株诞生
2009-07-31 22:05:51   来源：丁香园   作者：  评论：0 点击：

ScienceDaily (July 22, 2009) — According to the World Health Organization, approximately two billion people suffer from iron deficiency. They tire easily, experience problems in metabolizing harmful substances in their bodies and eventually suffer from anemia. Women and children are particularly affected in developing countries, where rice is the major staple food. Peeled rice, also called polished rice, does not have enough iron to satisfy the daily requirement, even if consumed in large quantities. For many people, a balanced diet or iron supplements are often unaffordable.
《每日科学》2009年7月22日报道——根据世界卫生组织的数据显示，世界上大约有2亿人患有缺铁。他们很容易疲倦，当体内有害物质代谢发生问题时，他们的身体就会最终得贫血。特别是在发展中国家，在那里大米是主要的主食，女人和儿童比较容易出现此类问题。去皮的大米,也称为精白米，即使大量食用也没有足够的铁来满足日常需要消耗。而且对许多人来说往往负担不起均衡的饮食或铁补充剂。 Rice actually has a lot of iron, but only in the seed coat. Because unpeeled rice quickly becomes rancid in tropical and subtropical climates, however, the seed coat - along with the precious iron - has to be removed for storage. Researchers working with Christof Sautter and Wilhelm Gruissem in the laboratory of plant biotechnology at ETH Zurich have now succeeded in increasing the iron content in polished rice by transferring two plant genes into an existing rice variety. Their work was published July 21 in the online edition of Plant Biotechnology Journal.
其实大米中有很多的铁,但是这些铁只有存在在种皮里。因为未剥皮的大米会在热带和亚热带气候中很快变质,因此,种皮——连同珍贵的铁都会被移除。苏黎世理工学院与Christof Sautter和Wilhelm Gruissem一起工作的植物生物技术实验室的研究人员，现在已经成功地通过转移两段植物基因到现有的稻株品种，开发出了铁含量增加的优质大米。他们的研究成果7月21日发表于《植物生物技术杂志》的网络版。
　　
Genes help to mobilize and store iron
基因帮助动员和储存铁

The rice plants express the two genes to produce the enzyme nicotianamin syn-thase, which mobilizes iron, and the protein ferritin, which stores iron. Their synergistic action allows the rice plant to absorb more iron from the soil and store it in the rice kernel. The product of nicotianamine synthase, called nicotianamin, binds the iron temporarily and facilitates its transportation in the plant. Ferritin acts as a storage depot for iron in both plants and humans. The researchers controlled the genes introduced in such a way that nicotianamin synthase is expressed throughout the rice plant, but ferritin only in the rice kernel. Together, the expression of the genes has a positive impact on iron accumulation in the rice kernel and increases the iron content more than six-fold compared to the original variety.

稻株表达这两种基因的结果是产生了一种酶（nicotianamin合成酶），这种酶可以动员铁和储存铁的铁蛋白。他们的协同作用可以使稻株从土壤中吸收更多的铁,并将其存储下来的铁与米粒紧密结合。其中nicotianamin合成酶的作用是暂时性地负载铁并且促进铁在植物中的转运，而铁蛋白的作用则是作为植物以及人体中铁的储存站。研究人员控制基因产生的作用中发现，nicotianamin合成酶的表达遍布稻株植物的各个部分，但是铁蛋白仅在米粒中。并且这种基因的表达在米粒的铁积累方面也有积极作用，同时可以使铁含量是最初品种的六倍多。

No negative impacts anticipated
预计没有负面影响

The ETH scientists are excited about the new rice variety. The prototypes behave normally in the greenhouse and show no signs of possible negative effects. "Next we will have to test whether the rice plants also perform well in the field under agronomical conditions", says Wilhelm Gruissem. The ETH Professor does not expect the plants to have a negative impact on the environment. It is unlikely that they will deplete the soil of iron, as iron is the most abundant metallic element in it.
ETH的科学家对这一稻株新品种十分兴奋。目前观察该品种在温室里的表现没有负面影响的迹象。Wilhelm Gruissem说：“下一步我们将测试这种稻株在田地以及农艺方面的表现。”ETH的教授不希望植物对环境造成负面影响。至于说这种稻株会耗尽土壤中的铁更是不可能的，因为铁是地球上最丰富的金属元素。

Distribution to farmers still many years away
向农民推广还需要很多年

The rice plants will have to undergo many greenhouse and field tests for bio-safety and agronomic performance before the high-iron rice varieties eventually become available to farmers. The current prototypes are unsuitable for agricultural production yet. Although the new rice variety already has an iron content that is nutritionally relevant, Gruissem wants to increase it further. After all, many people who suffer from iron deficiency can only afford one meal per day. If the scientists manage to increase iron in the rice kernel up to twelve-fold, one rice meal will be sufficient to satisfy the daily iron requirement.

在这种高铁稻株被农民利用前不得不在温室以及田地现场接受诸多的生物安全以及农艺方面的测试。因为当前的稻株原型还并不适合农业生产。尽管新稻株品种在营养上可以增加铁含量，但是Gruissem还期望更大的进步。毕竟，人们发生了铁缺乏不能仅仅靠每天的一顿饭来补充。如果科学家将米粒中铁含量提高到12倍，一顿米饭将有可能满足每日的铁需求。

The experience with the high-vitamin A "Golden Rice", which was developed at ETH Zurich in collaboration with researchers at the University of Freiburg (Germany), has shown that it takes years before genetically engineered rice can actually be planted by farmers. The regulatory hurdles and costs involved in making genetically modified plants available to agriculture and consumers are very high. The ETH scientists aim to make their high-iron rice plants available to small-scale and self-sufficient farmers free of charge.

此次试验与高维生素A的“黄金米”都是由苏黎世理工学院与德国弗赖堡大学合作完成的，这些试验结果都预示了转基因技术可以再不久的将来真正地被农民所使用。目前转基因植物的管制障碍以及成本对于农业和消费者来说都很高。EHT的科学家目的是使他们高铁稻株免费提供给小规模以及自给自足的农民们。