pho3: a phosphorus-deficient mutant of Arabidopsis thaliana (L.) Heynh.
A novel P-deficient mutant of Arabidopsis thaliana, pho3, was isolated by screening for root acid phosphatase (APase) activity in plants grown under low-P conditions. pho3 had 30% less APase activity in roots than the wild type and, in contrast to wild-type plants, root APase activity did not increase in response to growth in low P. However, shoot APase activity was higher in pho3 than in the wild-type plants. In addition, the pho3 mutant had a P-deficient phenotype, even when grown in P-sufficient conditions. The total P content of 11-d-old pho3 plants, grown in agar media with a plentiful supply of P, was about 25% lower than the wild-type level in the shoot, and about 65% lower in the roots. In the rosette leaves of mature soil-grown pho3 plants the total P content was again reduced, to about 50% of wild-type levels. pho3 exhibited a number of characteristics normally associated with low-P stress, including severely reduced growth, increased anthocyanin content (at least 100-fold greater than the wild type in soil-grown plants) and starch accumulation. The results suggest that the mutant is unable to respond to low internal P levels, and may lack a transporter or a signalling component involved in regulating P nutrition.
Zakhleniuk
O V
OV
Department of Biological Sciences, University of Essex, Colchester, UK.
Raines
C A
CA
Lloyd
J C
JC
D000135:Acid Phosphatase / Q000096:biosynthesis; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics*; D004790:Enzyme Induction; D017343:Genes, Plant; D009154:Mutation; D010641:Phenotype; D010758:Phosphorus / Q000032:analysis / Q000378:metabolism* / Q000494:pharmacology; D010860:Pigments, Biological / Q000032:analysis; D018517:Plant Roots / Q000201:enzymology; D018520:Plant Shoots / Q000201:enzymology; D013213:Starch / Q000378:metabolism
D010860:Pigments, Biological; D010758:Phosphorus; D013213:Starch; D000135:Acid Phosphatase