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Indian Journal of Biochemistry and Biophysics (IJBB) >
IJBB Vol.47 [2010] >
IJBB Vol.47(4) [August 2010] >
| Title: | Role of H2O2 and cell wall monoamine oxidases in germination of Vigna radiata seeds |
| Authors: | Verma, Giti
Sharma, Samir |
| Keywords: | Aromatic monoamines (AMA)
Monoamine oxidases (MAO)
Protein reserve mobilization
Reactive oxygen species (ROS)
Seed germination |
| Issue Date: | Aug-2010 |
| Publisher: | CSIR |
| Abstract: | Plant
cell wall expresses monoamine oxidases (MAOs) that catalyze oxidation of
secreted amines and produce H2O2 in the process. The H2O2,
so produced is used by cell wall peroxidases for lignification of cell wall or
for plant defense. The natural substrates for these MAOs are elusive, but
polyamines and certain catecholamines have been proposed as candidates.
Reactive oxygen species are also known to act as signaling molecules
controlling plant metabolism. Mungbean (Vigna
radiata) has long served as the plant model of choice while studying
molecular programs followed during germination and seed development. In this
study, we tested the effect of externally added MAO substrates epinephrine and
H2O2 on storage protein mobilization in germinating seeds
of Vigna radiata. The seeds were
imbibed in the presence of 50  M epinephrine and 10 M H2O2.
These low concentrations of the two compounds were used to exclude direct
effects on proteolysis and were arrived at after testing a range of the two and
choosing the most effective concentration. These seeds showed 11% and 7%
decrease in fresh weight respectively, indicating greater storage mobilization
and a corresponding 19% and 46% increase in axis length as compared to
untreated seeds. Soluble protein in seeds treated with epinephrine and H2O2
decreased significantly by 34% and 33% as compared to untreated seeds. Electrophoretic
analysis of seed proteins revealed a startling and selective depletion of
storage proteins in treated seeds. The results indicated a clear involvement of
H2O2 in storage protein mobilization in the cotyledons.
We propose that H2O2 generated within cell walls of seeds
serves as a signaling molecule guiding germination events, including protein
reserve mobilization. |
| Page(s): | 249-253 |
| ISSN: | 0975-0959 (Online); 0301-1208 (Print) |
| Source: | IJBB Vol.47(4) [August 2010]
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