Arabidopsis Root-Type Ferredoxin:NADP(H) Oxidoreductase 2 Is Involved in Detoxification of Nitrite in Roots

Hachiya, T., Ueda, N., Kitagawa, M., Hanke, G., Suzuki, A., Hase, T., Sakakibara, H. (September 2016) Arabidopsis Root-Type Ferredoxin:NADP(H) Oxidoreductase 2 Is Involved in Detoxification of Nitrite in Roots. Plant Cell Physiol, 57 (11). pp. 2440-2450. ISSN 1471-9053 (Electronic)0032-0781 (Linking)

DOI: 10.1093/pcp/pcw158


Ferredoxin : NADP(H) oxidoreductase (FNR) plays a key role in redox metabolism in plastids. Whereas leaf FNR (LFNR) is required for photosynthesis, root FNR (RFNR) is believed to provide electrons to ferredoxin (Fd)-dependent enzymes, including nitrite reductase (NiR) and Fd-glutamine-oxoglutarate aminotransferase (Fd-GOGAT) in non-photosynthetic conditions. In some herbal species, however, most nitrate reductase activity is located in photosynthetic organs, and ammonium in roots is assimilated mainly by Fd-independent NADH-GOGAT. Therefore, RFNR might have a limited impact on N assimilation in roots grown with nitrate or ammonium nitrogen sources. AtRFNRs are rapidly induced by application of toxic nitrite. Thus, we tested the hypothesis that RFNR could contribute to nitrite reduction in roots by comparing A. thaliana seedlings of wild type with loss-of-function mutants of RFNR2 When these seedlings were grown under nitrate, nitrite or ammonium, only nitrite nutrition caused impaired growth and nitrite accumulation in roots of rfnr2 Supplementation of nitrite with nitrate or ammonium as N sources did not restore the root growth in rfnr2 Also, a scavenger for nitric oxide (NO) could not effectively rescue the growth impairment. Thus, nitrite toxicity, rather than N depletion or nitrite-dependent NO production, probably causes the rfnr2 root growth defect. Our results strongly suggest that RFNR2 has a major role in reduction of toxic nitrite in roots. A specific set of genes related to nitrite reduction and the supply of reducing power responded to nitrite concomitantly, suggesting that the products of these genes act cooperatively with RFNR2 to reduce nitrite in roots.

Item Type: Paper
Uncontrolled Keywords: ferredoxin ferredoxin:NADP(H) oxidoreductse nitrite reduction root-type isoform
Subjects: organism description > plant > Arabidopsis
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > genes, structure and function > gene expression
CSHL Authors:
Communities: CSHL labs > Jackson lab
Depositing User: Matt Covey
Date: 11 September 2016
Date Deposited: 22 Sep 2016 16:42
Last Modified: 06 Mar 2017 21:55
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