Abstract:

Folates are small-molecule metabolites maintaining the normal life activities of organisms. The reduced pterins can participate in folate synthesis. We investigated the effects of the NADPH-dependent pterin reductase (PTR1) from Leishmania spp. on plant folate biosynthesis by over-expressing this gene in model plants Arabidopsis thaliana and tobacco (Nicotiana tabacum). The Leishmania PTR1 gene was cloned and transformed into Arabidopsis and tobacco, respectively, under the control of the constitutive promoter, and folates were measured in the transgenic overexpressors. The results showed that the folate content was enhanced significantly in the transformed plants. The content of 5-formyl-tetrahydrofolate in transgenic Arabidopsis plants was substantially increased, and that of 5-methyl-tetrahydrofolate in transgenic tobacco plants was markedly improved. This research indicated that introduction of PTR1 gene into plants could improve folate biosynthesis, which had provided technological bases for better understanding the rule of folate biosynthesis in plants.

Key words: folate metabolism, Leishmania PTR1 gene, pterin, Arabidopsis, tobacco

摘要：

叶酸是生物体维持正常生命活动所必需的小分子代谢物，还原态的蝶呤参与叶酸的合成。通过利用组成型启动子驱动依赖NADPH的蝶呤还原酶基因（NADPH-dependent pterin reductase gene, PTR1）在模式植物拟南芥和烟草中进行过表达,探讨了来源于利什曼原虫的PTR1基因对植物叶酸合成代谢的影响。结果表明，在过表达PTR1的转基因拟南芥和烟草植株中，叶酸含量有不同程度的升高，其中转基因拟南芥的5-甲酰四氢叶酸有显著提高,而转基因烟草中5-甲基四氢叶酸有显著提高。说明将来源于原生动物的蝶呤还原酶引入植物，可以促进转基因植物中叶酸的合成代谢，为深入了解植物叶酸合成代谢的规律奠定了基础。

关键词: 叶酸代谢;利什曼原虫PTR1基因;蝶呤;拟南芥;烟草