植物寡肽运输与硝酸根运输基因家族的研究进展

Progress on Nitrate and Oligopeptide Transporters in Plants

摘要:

氮素是植物生长发育的重要营养元素，也是限制植物生物量尤其是经济产量的关键营养元素之一。植物不仅能从外界获取无机氮素(硝酸根、铵根和尿素等)，还能以氨基酸、寡肽等形式获取有机氮素。植物已进化出复杂的运输系统来吸收与运输这些含氮化合物。硝酸根运输基因家族分为低亲和力硝酸根运输基因(low-affinity nitrate transporter family, NRT1)与高亲和力硝酸根运输基因(high-affinity nitrate transporter family, NRT2)两类。寡肽运输基因家族分为：运输含2~3个氨基酸残基的寡肽的PTR运输基因家族(peptide transporter family, PTR)和运输4~5个氨基酸残基的寡肽的OPT运输基因家族(oligopeptide transporter family, OPT)。其中NRT1与PTR在序列同源性上归属于同一基因家族，称作NRT1/PTR家族。对寡肽运输基因和硝酸根运输基因家族在植物生长发育中的生理、生化功能的研究进展进行了简要综述。

Abstract:

Nitrogen is one of the most important nutrients for plant growth, and one of key factors in limiting plant biomass and economic yield. Plants have evolved diverse and complex transport systems to facilitate uptake and reallocation of nitrogen compounds. Except uptake of inorganic nitrogen such as nitrate and ammonium by their specific transporters, plants can also uptake organic nitrogen including amino acids, small peptides and proteins by their corresponding transporters as nitrogen source. In higher plants, there are two types of nitrate transporters, known as low affinity nitrate transporter family (NRT1) and high affinity nitrate transporter family (NRT2). On the other hand, two families of small-peptide transporters have been recognized in eukaryotes, which are the oligopeptide transporter family (OPT) and the peptide transporter family (PTR). OPTs can transport tetra- and pentapeptides, while PTRs can transport di- and tripeptides. Interestingly, PTR family is similarity to NTR1 family based on their protein sequence, and their members usually mixed together to cluster into a homologous group called NTR1/PTR family. This article briefly reviewed on the research progress of nitrate transporter family and small-peptide transporter family in their substrates and physiological roles in plants.