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Regulation of maize root nitrate reductase mRNA levels
Author(s) -
Long Deborah M.,
Oaks Ann,
Rothstein Steven J.
Publication year - 1992
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1992.tb04755.x
Subject(s) - nitrate reductase , complementary dna , biology , messenger rna , reductase , cdna library , biochemistry , nad+ kinase , microbiology and biotechnology , enzyme , gene
The regulation of maize ( Zea mays L. cv. W64A x W182E) root nitrate reductase (NR) transcript levels has been investigated. To facilitate this process a partial nitrate reductase cDNA clone has been isolated from a maize root cDNA library. Its derived amino acid sequence was found to be more similar to that of the barley nicotinamide adenine dinucleotide (phosphate)‐reduced from [NAD(P)H] bispecific isoform of NR than to that of the maize leaf NADH:NR. The amount of NR mRNA in maize roots was found to increase very rapidly upon the addition of nitrate, reaching a maximum approximately 30 min after induction in the root tip. The level of NR mRNA was analysed in leaf and root tissue. There was very little cross‐hybridizing mRNA in leaf tissue when the root cDNA clone was used as a probe. Conversely, the leaf NADH:NR cDNA clone hybridized to an mRNA that was present at considerably higher levels in leaf tissue than in root tissue, although there was a clearly detectable level of this transcript present in the roots. Finally, the level of root NR mRNA was analyzed by using the tissue print technique to study its localization at the cellular level. The greatest amount of NR transcript was found in the region just above the root tip. At the cellular level, NR mRNA was found in all root cell types.