Abstract
Different organs of maize seedlings are known to contain different complements of NADH and NAD(P)H nitrate reductase (NR) activity. The study of the genetic programming that gives rise to such differences can be initiated by looking for genetic variants exhibiting different patterns of distribution of the above enzymes. We demonstrate in this work that scutella of very young maize seedlings contain NADH NR almost exclusively and that this activity is gradually replaced, as the seedling ages, with NAD(P)H NR. Leaves in the seedlings contain exclusively the NADH NR activity. A genetic variant is described that contains much reduced levels of NAD(P)H NR activity but not of NADH NR activity in the scutellum. This same variant exhibits a relatively low level of NAD(P)H NR but normal NADH NR activity in seedling root tips. These observations suggest that the genetic program used to specify the scutellar complement of NR activity shares some common components with the genetic program used to determine the young root tip complement of NR activities. Parts of regenerating callus at different stages of differentiation were examined to determine when the differences in NR complement begin to appear. The same pattern of NADH NR and NAD(P)H NR activities was found in unorganized as well as in organized callus, in recognizable root-like and even in green shoot-like material, both activities being present in all these tissues. An examination of the NR complement in different organs of a number of siblings originating from a cross involving transposon Mu-containing parents and having different levels of leaf NADH NR activity shows that the leaf NADH NR activity content and the scutellum NAD(P)H NR activity content are relatively independent of each other, indicating that the genetic programs specifying the NR content of these organs are not tightly coupled, if at all.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Dailey F. A., Kuo T., Warner R. L. Pyridine nucleotide specificity of barley nitrate reductase. Plant Physiol. 1982 May;69(5):1196–1199. doi: 10.1104/pp.69.5.1196. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nakagawa H., Poulle M., Oaks A. Characterization of Nitrate Reductase from Corn Leaves (Zea mays cv W64A x W182E) : Two Molecular Forms of the Enzyme. Plant Physiol. 1984 Jun;75(2):285–289. doi: 10.1104/pp.75.2.285. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Orihuel-Iranzo B., Campbell W. H. Development of NAD(P)H: and NADH:Nitrate Reductase Activities in Soybean Cotyledons. Plant Physiol. 1980 Apr;65(4):595–599. doi: 10.1104/pp.65.4.595. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Redinbaugh M. G., Campbell W. H. Purification and Characterization of NAD(P)H:Nitrate Reductase and NADH:Nitrate Reductase from Corn Roots. Plant Physiol. 1981 Jul;68(1):115–120. doi: 10.1104/pp.68.1.115. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shen T. C., Funkhouser E. A., Guerrero M. G. NADH- and NAD(P)H-Nitrate Reductases in Rice Seedlings. Plant Physiol. 1976 Sep;58(3):292–294. doi: 10.1104/pp.58.3.292. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Streit L., Nelson R. S., Harper J. E. Nitrate Reductases from Wild-Type and nr(1)-Mutant Soybean (Glycine max [L.] Merr.) Leaves : I. Purification, Kinetics, and Physical Properties. Plant Physiol. 1985 May;78(1):80–84. doi: 10.1104/pp.78.1.80. [DOI] [PMC free article] [PubMed] [Google Scholar]
- THORNE C. J., KAPLAN N. O. Physicochemical properties of pig and horse heart mitochondrial malate dehydrogenase. J Biol Chem. 1963 May;238:1861–1868. [PubMed] [Google Scholar]
- Wells G. N., Hageman R. H. Specificity for nicotinamide adenine dinucleotide by nitrate reductase from leaves. Plant Physiol. 1974 Aug;54(2):136–141. doi: 10.1104/pp.54.2.136. [DOI] [PMC free article] [PubMed] [Google Scholar]