Molecular cloning and characterization of an inorganic pyrophosphatase from barley.
A cDNA clone with sequence homology to soluble inorganic pyrophosphatase (IPPase) was isolated from a library of developing barley grains. The protein encoded by this clone was produced in transgenic Escherichia coli, and showed IPPase activity. In nondormant barley grains, the gene appeared to be expressed in metabolically active tissue such as root, shoot, embryo and aleurone. During inhibition, a continuous increase of the steady state mRNA level of IPPase was observed in embryos of non-dormant grains. In the embryos of dormant grains its production declined, after an initial increase. With isolated dormant and nondormant embryos, addition of recombinant IPPase, produced by E. coli, enhanced the germination rate. On the other hand, addition of pyrophosphate (PPi), substrate for this enzyme, appeared to reduce the germination rate. A role for this IPPase in germination is discussed.
Visser
K
K
Center for Phytotechnology, Leiden University/Netherlands Organization for Applied Scientific Research, Netherlands.
Heimovaara-Dijkstra
S
S
Kijne
J W
JW
Wang
M
M
D000040:Abscisic Acid / Q000096:biosynthesis; D000595:Amino Acid Sequence; D001483:Base Sequence; D011756:Diphosphates / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D015723:Gene Library; D018525:Germination / Q000502:physiology*; D001467:Hordeum / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D043564:Inorganic Pyrophosphatase; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011755:Pyrophosphatases / Q000235:genetics*; D012639:Seeds / Q000201:enzymology / Q000254:growth & development; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
D011756:Diphosphates; D010940:Plant Proteins; D000040:Abscisic Acid; D011755:Pyrophosphatases; D043564:Inorganic Pyrophosphatase