Chloroplast nitrite uptake is enhanced in Arabidopsis PII mutants.
In higher plants, the PII protein is a nuclear-encoded plastid protein that regulates the activity of a key enzyme of arginine biosynthesis. We have previously observed that Arabidopsis PII mutants are more sensitive to nitrite toxicity. Using intact chloroplasts isolated from Arabidopsis leaves and (15)N-labelled nitrite we show that a light-dependent nitrite uptake into chloroplasts is increased in PII knock-out mutants when compared to the wild-type. This leads to a higher incorporation of (15)N into ammonium and amino acids in the mutant chloroplasts. However, the uptake differences do not depend on GS/GOGAT activities. Our observations suggest that PII is involved in the regulation of nitrite uptake into higher plant chloroplasts.
Ferrario-Méry
Sylvie
S
Unité de Nutrition Azotée des Plantes, INRA, Route de St. Cyr, 78026 Versailles Cedex, France. ferrario@versailles.inra.fr
Meyer
Christian
C
Hodges
Michael
M
D027321:Anion Transport Proteins / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D001692:Biological Transport; D002736:Chloroplasts / Q000378:metabolism*; D004237:Diuron / Q000494:pharmacology; D009154:Mutation; D009573:Nitrites / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism; D051922:PII Nitrogen Regulatory Proteins / Q000235:genetics / Q000502:physiology*; D010788:Photosynthesis / Q000187:drug effects
D027321:Anion Transport Proteins; D029681:Arabidopsis Proteins; D009573:Nitrites; D051922:PII Nitrogen Regulatory Proteins; C473074:PII protein, Arabidopsis; D004237:Diuron; D009584:Nitrogen