Determination of Xanthine Dehydrogenase Activity in Nitrate Reductase Deficient Mutants of Pisum sativum and Arabidopsis thaliana

Jacobsen, E.; Braaksma, F. J.; Feenstra, W.J.

doi:10.1016/s0044-328x(84)80053-7

Cited by 16 publications

(7 citation statements)

References 16 publications

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“…Both vp14 and vp1 mutants did not show a reduction in either activity, indicating that these enzymes are not generally affected in other viviparous mutants (lanes 14 and 15). Aldehyde oxidase and XDH activities were assayed in shoot extracts from the same seedlings with similar results, except that chl6 mutants showed a low level of XDH activity in shoots, consistent with prior observations (data not shown; Jacobsen et al. , 1984).…”

Section: Resultssupporting

confidence: 85%

The maize Viviparous10/Viviparous13 locus encodes the Cnx1 gene required for molybdenum cofactor biosynthesis

Porch¹,

Tseung²,

Schmelz³

et al. 2005

The Plant Journal

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). † Present address: USDA-ARS-TARS, 2200 P. A. Campos Ave., Suite 201, Mayaguez, Puerto Rico, 00680. SummaryAbscisic acid (ABA), auxin and nitrate are important signaling molecules that affect plant growth responses to the environment. The synthesis or metabolism of these compounds depends on the molybdenum cofactor (MoCo). We show that maize (Zea mays) viviparous10 (vp10) mutants have strong precocious germination and seedling lethal phenotypes that cannot be rescued with tissue culture. We devised a novel PCR-based method to clone a transposon-tagged allele of vp10, and show that Vp10 encodes the ortholog of Cnx1, which catalyzes the final common step of MoCo synthesis. The seedling phenotype of vp10 mutants is consistent with disruptions in ABA and auxin biosynthesis, as well as a disruption in nitrate metabolism. Levels of ABA and auxin are reduced in vp10 mutants, and vp10 seedlings lack MoCo-dependent enzyme activities that are repairable with exogenous molybdenum. vp10 and an Arabidopsis cnx1 mutant, chlorate6 (chl6), have similar defects in aldehyde oxidase (AO) enzyme activity, which is required for ABA synthesis. Surprisingly, chl6 mutants do not show defects in abiotic stress responses. These observations confirm an orthologous function for Cnx1 and Vp10, as well as defining a characteristic viviparous phenotype to identify other maize cnx mutants. Finally, the vp10 mutant phenotype suggests that cnx mutants can have auxin-as well as ABAbiosynthesis defects, while the chl6 mutant phenotype suggests that low levels of AO activity are sufficient for normal abiotic stress responses.

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Section: Resultssupporting

confidence: 85%

The maize Viviparous10/Viviparous13 locus encodes the Cnx1 gene required for molybdenum cofactor biosynthesis

Porch¹,

Tseung²,

Schmelz³

et al. 2005

The Plant Journal

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“…Feenstra et al (1982) showed that acetylene reduction in a pea mutant deficient in NR activity was inhibited 28% less in the presence of NO; than that of the parent. The mutation appeared to be in the Mo-bearing cofactor, which also functions in other enzymes such as xanthine dehydrogenase (Jacobsen et al 1984), and it is possible that the response observed was due to other metabolic changes in addition to the loss of NR activity. Warner et al (1982) selected three NRdeficient mutants of pea; one, A3(X) also had defects in the Mo cofactor, while the other two, A317 and A334, appeared to have alterations in the structural gene of nitrate reductase.…”

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confidence: 99%

Effect of nitrate on nitrogen fixation and nodule carbohydrate and organic acid concentrations in pea mutants deficient in nitrate reductase

Nelson¹,

Edie²

1988

Physiologia Plantarum

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Nitrate inhibits symbiotic N2 fixation and a number of hypotheses concerned with NO3− assimilation have been suggested to explain this inhibition. These hypotheses were tested using a pea (Pisum sativum L. cv. Juneau) with normal nitrate reductase NR; (EC 1,6,6,4) activity and two mutants of cv. Juneau, A317 and A334, with impaired NR activity. The plants were inoculated with three strains of Rhizobium leguminosarum and grown for 3 weeks in N‐free medium, followed by 1 week in medium supplemented with 0, 5 or 10 mM KNO3 before harvesting. NO3 was taken up at comparable rates by the parent and the mutants and accumulated in leaf and stem tissue of the latter. Acetylene reduction rates were inhibited similarly in both the parent and mutants in the presence of KNO3 but there were differences among rhizobial strains. Starch concentration of the nodules decreased by 46% in the presence of KNO3 and there were differences among rhizobial strains but not among pea genotypes. Malate and succinate accumulated in nodules in the presence of KNO3. These data are not consistent with the photosynthate deprivation hypothesis as a primary mechanism for NO3 inhibition of N2 fixation since NO3 affected the nodule carbohydrate composition of all three pea genotypes in a similar manner. The lack of correlation between NR activity and NO3 inhibition of N2 fixation suggests that NO3 assimilation may be only indirectly involved in the inhibition phenomenon.

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“…The CcR activity was determined according to Wallace and Johnson [27] and is expressed as nmol cytochrome-c reduced per minute. XDH activity was assayed by a procedure of Scazzocchio et al [28], modified by Jacobsen et al [29]. One unit of XDH is defined as the increase in absorbance brought about by 0.25 ml of a 4 × 103-fold diluted suspension of xanthine oxidase from buttermilk {Sigma Chemical Company, St. Louis, MO).…”

Section: Enzyme Assaysmentioning

confidence: 99%

Biochemical characterization of some nitrate reductase deficient mutants of Nicotiana plumbaginifolia

Vries

Dirks

Mendel³

et al. 1986

Plant Science

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Determination of Xanthine Dehydrogenase Activity in Nitrate Reductase Deficient Mutants of Pisum sativum and Arabidopsis thaliana

Cited by 16 publications

References 16 publications

The maize Viviparous10/Viviparous13 locus encodes the Cnx1 gene required for molybdenum cofactor biosynthesis

The maize Viviparous10/Viviparous13 locus encodes the Cnx1 gene required for molybdenum cofactor biosynthesis

Effect of nitrate on nitrogen fixation and nodule carbohydrate and organic acid concentrations in pea mutants deficient in nitrate reductase

Biochemical characterization of some nitrate reductase deficient mutants of Nicotiana plumbaginifolia

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