|
KMID : 0613820130230040487
|
|
Journal of Life Science
2013 Volume.23 No. 4 p.487 ~ p.494
|
|
|
Salt Stress Responses of an Alanine Aminotransferase Knock-out Mutant of Rice (Oryza sativa L.)
|
|
Im Kyoung-Nam
Lee Chin-Bum
|
|
|
Abstract
|
|
|
|
An AlaAT knock-out mutant (alaat) of rice (Oryza sativa L.) was isolated from T-DNA tagging lines and the genotypes of its progeny were determined with AlaAT1-specific primers. The alaat phenotypes showed decreased growth and grain yield when compared with control plants. The activity of AlaAT1 in the mutant plants was practically undetectable. The responses of alaat plants to growth under salt stress were compared with those of control plants by measuring chlorophyll fluorescence and the activities and mRNA expression of antioxidant enzymes. All abiotic stresses tested (salt, drought, and chilling) caused a similar decrease in chlorophyll fluorescence in both alaat and wild type plants. The activity of peroxidase (POX), an antioxidant enzyme, decreased following salt treatment of alaat plants, while control plant showed an increased activity. The mRNA levels for cAPX (cytosolic ascorbate peroxidase), POX2, and AlaAT were determined by RT-PCR following salt stress. No AlaAT1 mRNA was detected in alaat plants. The POX2 mRNA showed a slightly increased level in the wild type but was not detected in alaat plants, in agreement with the activity assays. The levels of cAPX mRNA were greatly increased in both the wild type and alaat plants. The salt stress effects on rice plant growth are therefore proposed to reflect a loss of function of AlaAT, which alters the activity and synthesis of antioxidant enzymes (especially peroxidases), rather than a direct effect on photosynthesis.
|
|
|
KEYWORD
|
|
|
Alanine aminotransferase, Peroxidase, ascorbate peroxidase, salt stress, chlorophyll fluorescence
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
|
|