Soybean roots retain the seed urease isozyme synthesized during embryo development. [Glycine max (L. ) Merr]
- Univ. of Missouri, Columbia (USA)
Roots of young soybean (Glycine max (L.) Merr.) plants (up to 25 days old) contain two distinct urease isozymes, which are separable by hydroxyapatite chromatography. These two urease species (URE1 and URE2) differ in: (a) electrophoretic mobility in native gels, (b) pH dependence, and (c) recognition by a monoclonal antibody specific for the seed (embryo-specific) urease. By these parameters root URE1 urease is similar to the abundant embryo-specific urease isozyme, while root URE2 resembles the ubiquitous urease which has previously been found in all soybean tissues examined (leaf, embryo, seed coat, and cultured cells). The embryo-specific and ubiquitous urease isozymes are products of the Eu1 and Eu4 structural genes, respectively. Roots of the eu1-sun/eu1-sun genotype, which lacks the embryo-specific urease (i.e. seed urease-null), contain no URE1 urease activity. Roots of eu4/eu4, which lacks ubiquitous urease, lack the URE2 (leaflike) urease activity. From these genetic and biochemical criteria, then, we conclude that URE1 and URE2 are the embryo-specific and ubiquitous ureases, respectively. Adventitious roots generated from cuttings of any urease genotype lack URE1 activity. In seedling roots the seedlike (URE1) activity declines during development. Roots of 3-week-old plants contain 5% of the total URE1 activity of the radicle of 4-day-old seedlings, which, in turn, has approximately the same urease activity level as the dormant embryonic axis. The embryo-specific urease incorporates label from ({sup 35}S)methionine during embryo development but not during germination, indicating that there is no de novo synthesis of the embryo-specific (URE1) urease in the germinating root.
- OSTI ID:
- 5852848
- Journal Information:
- Plant Physiology; (USA), Vol. 94:2; ISSN 0032-0889
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GLYCINE HISPIDA
PHYSIOLOGY
ROOTS
ENZYME ACTIVITY
SEEDS
BIOSYNTHESIS
EMBRYOS
ISOENZYMES
METHIONINE
SULFUR 35
TRACER TECHNIQUES
AMINO ACIDS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
DAYS LIVING RADIOISOTOPES
DRUGS
EVEN-ODD NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
LEGUMINOSAE
LIGHT NUCLEI
LIPOTROPIC FACTORS
MAGNOLIOPHYTA
MAGNOLIOPSIDA
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PLANTS
RADIOISOTOPES
SULFUR ISOTOPES
SYNTHESIS
551001* - Physiological Systems- Tracer Techniques