Transcriptional control of the inducible nitrate reductase isoform from soybeans

John, Sabu; Malone, Mark J.; Watters, Michelle T.; Curtis, Luke

doi:10.1016/0006-291x(87)90769-8

Cited by 10 publications

(6 citation statements)

References 8 publications

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“…Non-legume plants, such as maize and tobacco, have been evaluated for response to common inhibitor effects on the gene encoding NRs [10,13]. Soybean N R has also be evaluated for feedback inhibition [22,30]. As expected, our data show that soybean iNR m R N A was inhibited by addition of glutamine to the growth medium (Fig.…”

Section: Discussionsupporting

confidence: 65%

“…It has been shown that barley NR expression is facilitated by phytochrome or another photoreceptor in etiolated seedlings but not in green leaves [24]. End products of nitrate assimilation, such as glutamine and other amino acids, also regulate NR expression [30]. Evaluation of regulation of nitrate assimilation and factors influencing NR gene expression is important in understanding nitrate assimilation and its interaction with nitrogen fixation in legumes.…”

Section: Introductionmentioning

confidence: 99%

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Identification of cDNA clones corresponding to two inducible nitrate reductase genes in soybean: analysis in wild-type and nr1 mutant

Kriz

et al. 1995

Plant Mol Biol

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Among higher plants, soybean is unique in that biochemically it has been characterized as having two constitutive nitrate reductase (cNR) isoforms and one substrate-inducible nitrate reductase (iNR) isoform in leaves. All three NR isoforms are expressed in cv. Williams 82 while the nr1 mutant expresses only the iNR isoform. The genetic and molecular mechanisms for regulation of these isoforms have not been elucidated. We describe here the isolation, by reverse transcription-polymerase chain reaction (RT-PCR), of two cDNA clones encoding soybean NR. They were designated as iNR1 and iNR2, respectively, since both were inducible by nitrate. The iNR1 and iNR2 cDNAs cover total encoding regions of 2661 and 2673 nucleotides, respectively. The iNR1 clone shows a 12 bp deletion at the 5' end, relative to iNR2. They show overall similarity of 89% at the nucleotide level, and 87% at the amino acid level. Like all plant NRs cloned so far, deduced amino acid sequences between iNR1 and iNR2 show greatest variation at the N-terminal region while no difference was observed at the C-terminus. Soybean iNR mRNAs were found to be different from those of maize and tobacco in response to tungsten inhibitor treatment, since the inhibitor decreased the steady-state levels of mRNA for soybean iNR and for NiR. Using the same 5' regions of both cDNAs as the probes, Southern blot analysis of genomic DNA revealed differences in organization between iNR1 and iNR2. The genomic DNA from wild-type Williams 82 soybean was shown to have three Eco RI fragments while the nr1 mutant lacked an 8 kb fragment when probed with iNR1 cDNA. Likewise, the nr1 mutant lacked three Hae III restriction fragments when probed with iNR1 cDNA. When probed with iNR2, both wildtype and nr1 mutant showed one identical Eco RI band and two identical Hae III bands. In northern blots, the steady-state level of iNR1 mRNA was similar for the nr1 mutant and the wild-type parent after 20 to 48 h induction by nitrate. Based on the Eco RI and Hae III restriction enzyme digestion patterns observed in Southern blot analysis of soybean DNA, it is concluded that in soybean iNR1 is encoded by a small multiple gene family and iNR2 is a single gene.

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Section: Discussionsupporting

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Identification of cDNA clones corresponding to two inducible nitrate reductase genes in soybean: analysis in wild-type and nr1 mutant

Kriz

et al. 1995

Plant Mol Biol

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“…Thus, conditions in which nitrate was eliminated from the growth medium and an alternative nitrogen source was provided had to be used. The use ofgln as the sole nitrogen source [21] fulfilled these two requirements and suppressed expression of the endogenous Nial *2 gene (Fig. 3, Table 1).…”

Section: Discussionmentioning

confidence: 99%

“…Genomic DNA was digested with Eco RI and Sal I restriction endonucleases prior to electrophoresis, and blotted to Zetaprobe nylon membrane (BioRad). The probe was a 3.1 kb Eco RI fragment from pAtc-46 [21] encoding the Nial*2 cDNA. Hybridization was performed at high stringency according to the manufacturer's protocol.…”

Section: Nucleic Acid Proceduresmentioning

confidence: 99%

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A chimeric Lhcb::Nia gene: an inducible counter selection system for mutants in the phytochrome signal transduction pathway

et al. 1995

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One approach towards understanding the transduction pathways of phytochromes is the selection of mutants impaired in various steps. We report here the construction of an inducible counter-selection system for such mutants employing the enzyme nitrate reductase. This enzyme can convert the benign substrate analogue chlorate to the toxic product chlorite, resulting in severe growth inhibition. An Arabidopsis thaliana nitrate reductase gene (Nial*2) was placed under the regulation of an Arabidopsis thaliana light-harvesting chlorophyll a/b protein (Lhcb1*3) promoter that is phytochrome-responsive. The chimeric Lhcb::Nia gene was transformed into A. thaliana. Homozygous transformant lines were selected and grown in the absence of nitrate and the presence of L-glutamine, conditions that substantially inhibited the expression of the endogenous nitrate reductase genes. In darkness seedlings of the transformed lines were resistant to chlorate; however, when seedlings were grown with intermittent red light, increased sensitivity to chlorate was observed. This sensitivity was correlated with an increase in both Nia1*2 RNA levels and nitrate reductase activity. The resistant seedlings were clearly distinguishable from the sensitive ones based on hypocotyl length, with no overlap in this parameter between the two populations. Thus, this system should allow for the selection of mutants that are impaired in phytochrome regulation of the transcription of Lhcb genes.

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The Regulation of Nitrate Assimilation in Yeast

Hipkin

1990

Inorganic Nitrogen in Plants and Microorganisms

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Transcriptional control of the inducible nitrate reductase isoform from soybeans

Cited by 10 publications

References 8 publications

Identification of cDNA clones corresponding to two inducible nitrate reductase genes in soybean: analysis in wild-type and nr1 mutant

Identification of cDNA clones corresponding to two inducible nitrate reductase genes in soybean: analysis in wild-type and nr1 mutant

A chimeric Lhcb::Nia gene: an inducible counter selection system for mutants in the phytochrome signal transduction pathway

The Regulation of Nitrate Assimilation in Yeast

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