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铁蛋白是一种由24个亚基组成的高分子贮藏蛋白质,可以储存多达4500个铁原子,在动植物及微生物的新陈代谢中起着非常重要的作用。有研究表明,外源铁蛋白的大量表达可以提高植物储存铁离子的能力。为了明确外源铁蛋白基因转化植物中内源铁蛋白基因差异表达与植物含铁量的关系,本研究在成功获得2个烟草铁蛋白基因的全长cDNA克隆NtFer1(登录号:ay083924)和NtFer2(登录号:ay141105)的基础上,以烟草品种SR-1(Nicotianatabacumcv.PetitHavanaSR-1)为受体,培育了转铁蛋白基因烟草。将双元载体pBI121中的GUS基因用来自大豆的铁蛋白基因SoyFer1(登录号:m64337)置换,利用农杆菌介导法转化烟草叶盘,获得在CaMV35S启动子驱动表达的大豆铁蛋白基因转化烟草植株。Northern杂交和Western杂交分析表明外源铁蛋白基因在转基因烟草中得到了正确表达。比较转基因烟草和非转基因烟草的内源铁蛋白基因表达强度、叶片铁含量、根系铁还原酶活性、株高和鲜重表明,外源铁蛋白基因不但促进了NtFer1的表达,提高转基因植株的储存铁的能力和根系铁还原酶活性,而且促进植株的生长速度。以上结果说明,外源铁蛋白基因转化烟草中内源铁蛋白基因的表达、铁离子的还原吸收及光和作用都得到了进一步的提高。
Ferritin, a 24-subunit polymer storage protein that stores up to 4,500 iron atoms, plays an important role in the metabolism of animals, plants and microorganisms. Studies have shown that the large number of exogenous ferritin expression can increase the plant’s ability to store ferric ions. In order to clarify the relationship between the differential expression of endogenous ferritin gene and the iron content in plants transformed with exogenous ferritin, two full-length cDNA clones of NtFer1 (accession number: ay083924) and NtFer2 (Accession Number: ay141105), a tobacco cultivar of transferrin gene was cultivated with the tobacco variety SR-1 (Nicotiana tabacumcv. PetitHavana SR-1) as a receptor. The GUS gene in the binary vector pBI121 was replaced with SoyFer1 (accession number: m64337) of ferritin from soybean, and the leaf discs of tobacco were transformed by Agrobacterium-mediated transformation to obtain the soybean ferritin gene-transformed tobacco that is driven by CaMV35S promoter Plant. Northern hybridization and Western blot analysis showed that exogenous ferritin gene was correctly expressed in transgenic tobacco. Comparison of endogenous ferritin gene expression intensity, leaf iron content, root iron reductase activity, plant height and fresh weight of transgenic tobacco and non-transgenic tobacco showed that the exogenous ferritin gene not only promoted the expression of NtFer1 and increased the storage of transgenic plants Iron capacity and root iron reductase activity, but also to promote plant growth rate. The above results show that exogenous ferritin gene transformation of tobacco endogenous ferritin gene expression, reduction and absorption of iron ions and light have been further enhanced.