Research articles
ScienceAsia 49 (2023):ID 646-652 |doi:
10.2306/scienceasia1513-1874.2023.065
Effects of calmodulin overexpression on gamma-aminobutyric
acid (GABA) levels and glutamate decarboxylase activity in
rice seedlings
Potitorn Kanchitanuraka,c, Supachitra Chadchawanb, Teerapong Buaboochac,*
ABSTRACT: The transgenic ?Khao Dawk Mali 105? (KDML105) rice (Oryza sativa L.) lines overexpressing OsCam1-1
calmodulin gene are more tolerant to salt stress and drought than the wild type (WT) plants. Here, we examined
the production of gamma-aminobutyric acid (GABA) and glutamate decarboxylase (GAD) during germination in such
plants. During the first 24 h of soaking in water under normal conditions, the GABA content increased to a higher
degree in all transgenic rice lines than in the WT. During seed germination (from day 2 to day 4) under both normal
and salt stress conditions, the GABA content in all rice lines rapidly increased. GABA content under salt stress conditions
then continued to increase and reached higher levels in all transgenic overexpression lines than in WT after 6?8 days
of germination. Two of the three transgenic overexpression lines also exhibited statistically significantly higher GAD
activity while the other line had a trend of having higher activity compared to the WT. These results suggest that
transgenic rice plants overexpressing OsCam1-1 had enhanced GAD activity facilitated by calmodulin overexpression,
resulting in higher GABA content.
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a |
Biotechnology Program, Faculty of Science, Chulalongkorn University, Bangkok 10330 Thailand |
b |
Center of Excellence in Environment and Plant Physiology, Department of Botany, Faculty of Science,
Chulalongkorn University, Bangkok 10330 Thailand |
c |
Center of Excellence for Molecular Crop, Department of Biochemistry, Faculty of Science, Chulalongkorn University,
Bangkok 10330 Thailand |
* Corresponding author, E-mail: Teerapong.B@chula.ac.th
Received 4 Dec 2022, Accepted 17 Jun 2023
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