The influence of chlorsulfuron herbicide on GABA metabolism and oxidative damage in lentil (Lens culinaris Medik) and wheat (Triticum aestivum L.) seedlings

Abstract

Abiotic stresses like salinity, drought, cold, heat, nutrient deficiency, and nutrient toxicity act as a major threats for crops quality and productivity. Herbicides are large category of chemical classes that affect various metabolic pathways and energy cascade in plants. γ-aminobutyric acid (GABA) is proposed to be critically involved in nitrogen metabolism, cytosolic pH regulation, and protection against oxidative imbalance in response to a wide range of abiotic stresses in plants. The objectives of this study were to determine the influence of chlorsulfuron herbicide on GABA metabolism and oxidative damage in two wheat (Triticumaestivum L.) cultivars (Hurani 75 and Um Qayes) and two lentil cultivars (Jordan 1 and Jordan 2) with respect to seed germination, GABA and malondialdehyde (MDA) levels accumulation, transcription of glutamate decarboxylase gene (GAD) mRNA level, total proteins, and carbohydrates contents. A significant increase in GABA, MDA and GAD mRNA level, proteins, and carbohydrates contents under chlorsulfuron treatments in the wheat and lentil cultivars was found in this study. The significant increase in GAD gene expression indicates the increase in GABA level under chlorsulfuron treatments. Hurani 75 and Jordan 2 cultivars showed significant decrease in protein level at high concentration of chlorsulfuron, whereas Um Qayes and Jordan 1 cultivars showed more tolerance under the same treatments. This study indicates that GABA metabolism might be one of multiple integrated signaling and metabolic pathways of herbicide stress adaptation and tolerance in wheat and lentil seedlings. This suggests that GABA molecule may act as a protective and metabolic signaling molecule in carbohydrates and proteins metabolism in plants under herbicidal treatments.