Uracil salvage is necessary for early Arabidopsis development.
Uridine nucleotides can be formed by energy-consuming de novo synthesis or by the energy-saving recycling of nucleobases resulting from nucleotide catabolism. Uracil phosphoribosyltransferases (UPRTs; EC 2.4.2.9) are involved in the salvage of pyrimidines by catalyzing the formation of uridine monophosphate (UMP) from uracil and phosphoribosylpyrophosphate. To date, UPRTs are described as non-essential, energy-saving enzymes. In the present work, the six genes annotated as UPRTs in the Arabidopsis genome are examined through phylogenetic and functional complementation approaches and the available T-DNA insertion mutants are characterized. We show that a single nuclear gene encoding a protein targeted to plastids, UPP, is responsible for almost all UPRT activity in Arabidopsis. The inability to salvage uracil caused a light-dependent dramatic pale-green to albino phenotype, dwarfism and the inability to produce viable progeny in loss-of-function mutants. Plastid biogenesis and starch accumulation were affected in all analysed tissues, with the exception of stomata. Therefore we propose that uracil salvage is of major importance for plant development.
Mainguet
Samuel E
SE
URGV, UMR 1165 Institut National de la Recherche Agronomique-CNRS, Evry cedex, France.
Gakière
Bertrand
B
Majira
Amel
A
Pelletier
Sandra
S
Bringel
Françoise
F
Guérard
Florence
F
Caboche
Michel
M
Berthomé
Richard
R
Renou
Jean Pierre
JP
D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D019143:Evolution, Molecular; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D016254:Mutagenesis, Insertional; D010430:Pentosyltransferases / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D014498:Uracil / Q000378:metabolism*
D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D018744:DNA, Plant; C036483:T-DNA; D014498:Uracil; D010430:Pentosyltransferases; C023269:uracil phosphoribosyltransferase