Intrinsic GUS-like activities in seed plants.

Area of Science:

• Plant biochemistry
• Enzymology

Background:

• Beta-glucuronidase enzymes play various roles in biological systems.
• Understanding plant-specific enzyme activities is crucial for plant science.

Purpose of the Study:

• To survey intrinsic beta-glucuronidase-like activities across diverse plant species.
• To investigate the localization and behavior of these activities in plant tissues.

Main Methods:

• Histochemical assays with overnight incubation.
• Qualitative fluorometric assays with 24-hour incubation.
• In vitro culturing of excised embryos.
• Germination studies of mature seeds.

Main Results:

• Beta-glucuronidase-like activities were detected in fruit walls, seed coats, endosperms, and particularly embryos of 52 plant species.
• Activities in soybean and string bean embryos diminished rapidly during in vitro culture and seed germination.
• Vegetative organs of seedlings and mature plants generally lacked these activities.
• The plant enzyme(s) were antigenically distinct from E. coli beta-glucuronidase.

Conclusions:

• Intrinsic beta-glucuronidase-like activities are predominantly localized in reproductive plant structures.
• These activities are dynamic, decreasing with development and germination.
• Plant beta-glucuronidase-like enzymes are distinct from their bacterial counterparts.