Genomic analysis of the nitrate response using a nitrate reductase-null mutant of Arabidopsis.
A nitrate reductase (NR)-null mutant of Arabidopsis was constructed that had a deletion of the major NR gene NIA2 and an insertion in the NIA1 NR gene. This mutant had no detectable NR activity and could not use nitrate as the sole nitrogen source. Starch mobilization was not induced by nitrate in this mutant but was induced by ammonium, indicating that nitrate was not the signal for this process. Microarray analysis of gene expression revealed that 595 genes responded to nitrate (5 mm nitrate for 2 h) in both wild-type and mutant plants. This group of genes was overrepresented most significantly in the functional categories of energy, metabolism, and glycolysis and gluconeogenesis. Because the nitrate response of these genes was NR independent, nitrate and not a downstream metabolite served as the signal. The microarray analysis also revealed that shoots can be as responsive to nitrate as roots, yet there was substantial organ specificity to the nitrate response.
Wang
Rongchen
R
Section of Cell and Developmental Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA.
Tischner
Rudolf
R
Gutiérrez
Rodrigo A
RA
Hoffman
Maren
M
Xing
Xiujuan
X
Chen
Mingsheng
M
Coruzzi
Gloria
G
Crawford
Nigel M
NM
D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D018744:DNA, Plant / Q000235:genetics; D020869:Gene Expression Profiling; D018745:Genome, Plant; D009154:Mutation; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000235:genetics* / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism / Q000494:pharmacology*; D020411:Oligonucleotide Array Sequence Analysis
D018744:DNA, Plant; D009566:Nitrates; D009565:Nitrate Reductases; D050901:Nitrate Reductase