Regulation of GmNRT2 expression and nitrate transport activity in roots of soybean (Glycine max)

被引：72

作者：

Ranamalie Amarasinghe B.H.R. ^{[1
]}

De Bruxelles G.L. ^{[1
]}

Braddon M. ^{[1
]}

Onyeocha I. ^{[2
]}

Forde B.G. ^{[2
]}

Udvardi M.K. ^{[1
]}

机构：

[1] Division of Biochemistry, Faculty of Science, Australian National University, Canberra

[2] Biochemistry Department, IACR-Rothamsted, Harpenden, Herts

来源：

Planta | 1998年 / 206卷 / 1期

基金：

澳大利亚研究理事会;

关键词：

Glycine (nitrate transport); High-affinity nitrate transporter; Major facilitator superfamily; Nitrate induction; Nutrient uptake;

D O I：

10.1007/s004250050372

中图分类号：

学科分类号：

摘要：

A full-length cDNA, GmNRT2, encoding a putative high-affinity nitrate transporter was isolated from a Glycine max (L.) root cDNA library and sequenced. The deduced GmNRT2 protein is 530 amino acids in length and contains 12 putative membrane-spanning domains and a long, hydrophilic C-terminal domain. GmNRT2 is related to high-affinity nitrate transporters in the eukaryotes Chlamydomonas reinhardtii and Aspergillus nidulans, and to putative high-affinity nitrate transporters in barley and tobacco. Southern blot analysis indicated that GmNRT2 is part of a small, multigene family in soybean. Expression of GmNRT2 in roots was regulated by the type of nitrogen source provided to plants: GmNRT2 mRNA levels were barely detectable in ammonium-grown plants, higher in nitrogen-deprived plants, and highest in nitrate-grown plants. Induction of GmNRT2 mRNA levels in roots occurred within 1 h after exposure of plants to nitrate. Nitrate induction of GmNRT2 mRNA levels was accompanied by a fourfold increase in net nitrate uptake by soybean roots at 100 μM external nitrate. The molecular and physiological evidence indicates that GmNRT2 is probably a high-affinity nitrate transporter involved in nitrate uptake by soybean roots.

引用

页码：44 / 52

页数：8

共 47 条

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