Molecular Cloning of Complementary DNA Encoding Maize Nitrite Reductase

Abstract

Complementary DNA has been isolated that codes for maize nitrite reductase (NiR) by using the corresponding spinach gene (E Back et al. 1988 Mol Gen Genet 212:20-26) as a heterologous probe. The sequences of the complementary DNAs from the two species are 66% homologous while the deduced amino acid sequences are 86% similar when analogous amino acids are included. A high percentage of the differences in the DNA sequences is due to the extremely strong bias in the corn gene to have a G/C base in the third codon position with 559/569 codons ending in a G or C. Using a hydroponic system, maize seedlings grown in the absence of an exogenous nitrogen source were induced with nitrate or

Transient Accumulation of Nitrite Reductase mRNA in Maize following the Addition of Nitrate

“…10 and references therein). It has been shown for both NR in several plant species (5,7,9) and for NiR in spinach and maize (3,16) (2,8).…”

“…Two salt media were used: (a) minimal medium, 10 mM Mes (pH 5.5), 5 mM CaSO4; (b) complete medium (minus nitrogen), 5 For RNA blot hybridization, 20 ,g of leaf or 10 ,ug of root total cellular RNA was subjected to electrophoresis through a 1.2% agarose, 2.2 M formaldehyde gel, and the RNA was blotted onto nitrocellulose. The probe used for the hybridization was a NiR cDNA insert from the plasmid pCIB801 (16). Filters were allowed to decay and then rehybridized with nick-translated soybean actin gene (19).…”

“…[10] for a review). With the cloning of these genes, it has been possible to demonstrate that the mRNA levels for these genes increase considerably upon the addition of nitrate (3,5,7,9,16). The rate with which nitrate is taken into root tissue has also been shown to be increased in the presence of nitrate (13).…”

“…In this paper, we utilize a maize NiR cDNA clone (16) as a probe to analyze the regulation by nitrate of NiR gene expression in hydroponically grown maize seedlings. Upon addition of nitrate to the medium, a rapid induction in the NiR mRNA levels is seen.…”

A Nitrate-Inducible Ferredoxin in Maize Roots (Genomic Organization and Differential Expression of Two Nonphotosynthetic Ferredoxin Isoproteins)

“…The blots were probed with various cDNA inserts that had been labeled with [a-32 P]dCTP. cDNAs for FNR, NiR, and ubiquitin, which had originally been cloned by Ritchie et al (1994), Lahners et al (1988), and Liu et al (1995), respectively, were isolated from the maize root cDNA library with appropriate oligonucleotide DNAs as the probes. The probes were synthesized on the basis of the published sequences.…”