GrainGenes Reference Report: PPS-122-783
Reference
PPS-122-783
Title
Isolation and characterization of HvNRT2.3 and HvNRT2.4, cDNAs encoding high-affinity nitrate transporters from roots of barley
Journal
Plant Physiology
Year
2000
Volume
122
Pages
783-792
Author
Vidmar JJ Zhuo D Siddiqi MY Glass ADM
Abstract
Summary: Two full-length cDNAs, HvNRT2.3 and HvNRT2.4, were isolated from roots of barley (Hordeum vulgare), using reverse transcriptase-PCR and RACE-PCR. The corresponding polypeptides, consisting of 507 amino acids (molecular masses of 54.6 kD), belong to the major facilitator superfamily (MFS), and are closely related (> 87% identity) to those encoded by HvNRT2.1 and HvNRT2.2 (formerly BCH1 and BCH2, respectively) from roots of barley. The latter are considered to encode inducible high-affinity NO3(-) transporters (Trueman et al., 1996). HvNRT2 transcripts were undetectable in NO3(-)-deprived plants. Following exposure to either NO3(-) or NO2(-), transcript abundance and (13)NO3(-) influx increased to a maximum by 6 to 12 h, then declined in HvNRT2.1, HvNRT2.2, and HvNRT2.3. The pattern of HvNRT2.4 transcript abundance was different, remaining high after achieving peak abundance. When external NO3(-) concentrations were varied from 0 to 500 micromolar under steady-state conditions of NO3(-) supply, HvNRT2 transcript accumulation and (13)NO3(-) influx were highest in 50 micromolar NO3(-)-grown plants. When NH4(+) was provided together with NO3(-), transcript accumulation during the first 2 h was similar to that due to NO3(-) alone, but by 4 h the transcript level was significantly reduced. HvNRT2 transcript was undetectable in leaf tissues
Keyword
GrainGenes is a product of the Agricultural Research Service of the US Department of Agriculture.
GrainGenes Reference Report: PPS-122-783
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GrainGenes is a product of the Agricultural Research Service of the US Department of Agriculture. | |||