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Developmental expression of genetically defined peptidases in maize.
1Department of Genetics, North Carolina State University, Raleigh, North Carolina 27650.
Plant Physiology
|June 1, 1979
Summary
Maize peptidase activity is highest in immature kernels and declines with drying. Paternally contributed peptidase variants appear early, with specific isozymes like AMP2 showing tissue-specific expression in endosperm.
Area of Science:
- Plant Biochemistry
- Molecular Biology
- Maize Genetics
Background:
- Peptidases play crucial roles in protein metabolism within plants.
- Understanding peptidase activity in maize is vital for crop development and yield.
Purpose of the Study:
- To compare the activities of genetically defined amino- and endopeptidases in different maize kernel tissues.
- To investigate the expression of paternally contributed peptidase genes during early development.
- To determine the role of peptidases in maize germination and seedling growth.
Main Methods:
- Comparative analysis of peptidase activities in pericarp, endosperm, and embryonic tissues.
- Examination of peptidase gene expression in F(1) crosses using pollen parent contribution.
- Isozyme analysis and subcellular fractionation of maize scutellum.
Main Results:
- Peptidase activities were highest in immature maize kernels and decreased as the kernel dried.
- Paternally contributed peptidase variants were detectable as early as 7 days post-pollination.
- Peptidase activity declined in the endosperm but remained high in the scutellum during germination.
- A specific aminopeptidase isozyme (AMP2) exhibited endosperm-specific localization during kernel maturation.
Conclusions:
- Maize peptidase activity is developmentally regulated and tissue-specific.
- Paternal gene expression contributes to peptidase diversity in developing maize kernels.
- Maize peptidases likely do not directly hydrolyze storage proteins during germination and growth.