A reappraisal of nitrate inhibition of nitrogenase in A317, a nitrate reductase-deficient mutant of pea (Pisum sativum)

Walsh, K.B. and Carroll, B.J. (1992) A reappraisal of nitrate inhibition of nitrogenase in A317, a nitrate reductase-deficient mutant of pea (Pisum sativum). Physiologia Plantarum, 84 2: 283-291. doi:10.1034/j.1399-3054.1992.840215.x


Author Walsh, K.B.
Carroll, B.J.
Title A reappraisal of nitrate inhibition of nitrogenase in A317, a nitrate reductase-deficient mutant of pea (Pisum sativum)
Formatted title
A reappraisal of nitrate inhibition of nitrogenase in A317, a nitrate reductase-deficient mutant of pea (Pisum sativum)
Journal name Physiologia Plantarum   Check publisher's open access policy
ISSN 0031-9317
1399-3054
Publication date 1992-02-01
Sub-type Article (original research)
DOI 10.1034/j.1399-3054.1992.840215.x
Volume 84
Issue 2
Start page 283
End page 291
Total pages 9
Place of publication Malden, MA, United States
Publisher Wiley-Blackwell Publishing
Language eng
Abstract Symbiotic plants of Pisum sativum L. cv. Juneau and its nitrate reductase-(EC 1. 6. 6. 1)-deficient mutant, A317, were exposed to nitrate for up to 8 days and assessed for nitrate assimilation, nitrogenase activity and nodule carbohydrate status. The mutant, A317, was not impaired in its ability to absorb nitrate over up to 8 days, but was leakier with respect to nitrate reduction ability than previously realized, as 63% of the nitrate absorbed by the plant over 8 days was assimilated (in contrast to 93% in the wild type). After 2 days exposure to 5 mM nitrate, nitrogenase (EC 1.18.2.1) activity was less affected in A317 (84% of initial) than in Juneau (46% of initial): nodule starch reserves were less depleted in A317 (70% of initial) than in Juneau (26% of initial). It was concluded that nitrate reduction is a major cause of nitrate inhibition of nodule activity, and that its effect may be mediated through a decrease in the availability of carbohydrate to the nodules. Longer term (> 4 day) exposure of A317 plants to nitrate resulted in accumulation of nitrate in plant tissues, an associated necrosis of shoot tissue, a marked decrease in nodule starch content and a severe inhibition of nodule activity. This consideration of the effect of the duration of exposure to nitrate is used to resolve a discrepancy between previous reports on the sensitivity to nitrate of nitrogenase activity in nitrate reductase-deficient mutants of pea.
Keyword Carbohydrate Deprivation
Carbon Partitioning
Nitrate
Nitrate Reductase Mutant
Nitrogenase Inhibition
Pisum-Sativum
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Chemistry and Molecular Biosciences
 
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