Effect of Drought Stress on Wheat (Triticum durum L.) Growth and Metabolism: Insight from GABA Shunt, Reactive Oxygen Species and Dehydrin Genes Expression

Title : Effect of Drought Stress on Wheat (Triticum durum L.) Growth and Metabolism: Insight from GABA Shunt, Reactive Oxygen Species and Dehydrin Genes Expression

Abstract:

This study investigated the physiological, biochemical, and molecular mechanisms that triggered in post-germination and seedlings of four durum wheat (Triticum durum L.) cultivars (Umqais, Hurani75, Sham1, and Acsad65) in response to water deficit (80%, 50% and 20% water holding capacity) through the characterization of seed germination pattern, seedling growth (plant height, fresh and dry weight, and water content), GABA shunt metabolite levels (GABA, Glutamate, and Alanine), oxidative damage (malondialdehyde (MDA) level) and the expression of glutamate decarboxylase (GAD) and dehydrins (dhn and wcor) genes. Data showed a significant decrease (P ≤ 0.05) in seeds germination percentage, seedling length, fresh weight, dry weight, and water content as water availability was decreased. GABA shunt metabolites abundances were significantly increased with negative correlation under all water stress treatments. MDA content increased in post-germination and seedling stages in all durum wheat cultivars under all water stress levels. However, decreased water content and prolonged exposure of durum wheat cultivars to drought stress increased the GAD expression that activated GABA shunt pathway especially at seedlings growth stage. The activation of GABA shunt through up-regulation of GAD expression was correlated with GABA accumulation to maintain carbon-nitrogen balance, metabolism of amino acids and carbohydrates, and the regulation of growth under drought stress. dhn and wcor mRNA transcript significantly increased as water availability decreased in all wheat cultivars during post-germination stage to enhance drought tolerant by membrane protection, cryoprotection of enzymes and prevent ROS accumulation in response to drought stress. Generally, our data clearly showed that different durum wheat cultivars responded differently to water stress during seedling growth stage. The degree of tolerance in durum wheat might be connected with ROS scavenging systems and the activation of antioxidant enzymes that was associated with activation of GABA shunt pathway and the production of GABA in response to drought stress

Biography:

Biographical sketch: Nisreen AL-Quraan graduated in 1998 with Bachelor of Science degree from the Department of Biological Sciences, Yarmouk University, Jordan. She joined the graduate program in the Department of Biological sciences, Yarmouk University and received her Master of Science degree in Plant Biochemistry and Molecular biology in 2001. After completion of her MS, she worked as research and teaching assistant for two years in the Department of Biological Sciences, Yarmouk University, Jordan. On May, 2004 she joined the Department of Biological Sciences, Auburn University, Alabama, USA to pursue her PhD degree in Plant Biochemistry and Molecular Biology working on the plant abiotic stress interaction and the role of GABA shunt pathway in plant stress tolerance. She obtained her PhD Degree in August, 2008 from Auburn University, Alabama, USA. Since September 2008, Nisreen AL-Quraan has been working as a professor in plant biochemistry and molecular biology at Jordan University of Science and Technology, JORDAN. Her research is focusing on investigating the pathways that enable plants to adapt and tolerate harsh biotic and Abiotic stress conditions. She is interested in understanding the role of GABA shunt metabolic pathway that is activated in response to the interactions between plants and its environments.

Research interest: Plant Biochemistry and Molecular Biology, Plant and Environment, Stress Physiology