The Department of Biology at the College of Education for Pure Sciences (Ibn Al-Haitham) held a PhD dissertation defense in Pure Sciences by researcher Wafaa Hameed Majeed Mohammed, entitled: “A Physiological and Molecular Study of the Role of Brassinolide and Gamma-Aminobutyric Acid in Iron-Deficiency Stress Tolerance in Wheat (Triticum aestivum L.)”, under the supervision of Asst. Prof. Dr. Asaad Kadhim Abdullah.
The study addressed an important issue in plant physiology and agricultural production, focusing on the effects of iron deficiency stress on wheat growth, nutritional efficiency, and productivity. Particular attention was given to the potential role of hormonal treatments, especially brassinolide and gamma-aminobutyric acid (GABA), in enhancing plant adaptation to stress conditions and improving iron uptake and utilization efficiency.
The study aimed to identify the genetic and physiological variation among the investigated wheat cultivars in their responses to iron-deficiency stress and to evaluate their adaptive capacity under different levels of iron availability. It also investigated the relative changes in the expression of several genes involved in iron uptake, transport, and metabolism, including TaNAS, TaNAAT, TaDMAS, TaTOM, and TaYSL, and examined their responses to different iron levels and the applied hormonal treatments.
The research further focused on the physiological, biochemical, and molecular responses associated with iron deficiency by evaluating growth-related indicators, elemental balance, and selected organic acids involved in iron uptake and stress-adaptation mechanisms. In addition, the study evaluated the effectiveness of hormonal treatments in enhancing physiological traits associated with iron-uptake efficiency and stress tolerance.
The findings highlighted the importance of an integrated relationship among physiological, biochemical, and molecular indicators in elucidating the mechanisms responsible for improving the nutritional efficiency and productivity of wheat cultivars under iron-deficiency conditions. The Lateefa and Super Max cultivars emerged as promising candidates for future studies on iron-stress tolerance, owing to their demonstrated capacity to improve growth indicators and regulate the expression of genes associated with iron uptake.
Correlation analysis also revealed significant positive relationships between gene-expression levels and grain yield, with TaTOM, TaNAAT, and TaDMAS emerging as among the genes most strongly associated with productive traits. These findings highlight their potential as promising molecular markers in wheat breeding programs aimed at improving iron-uptake efficiency and enhancing productivity under iron-deficiency stress.
The study recommended further investigations into iron-chelation pathways, particularly the enzymatic activities associated with TaNAAT and TaDMAS, as well as studies on antioxidant enzymes such as SOD, CAT, and POD to clarify their roles in reducing oxidative stress and improving plant growth under iron deficiency. It also recommended expanding research on the relationship between organic-acid accumulation, enzymatic activity, and gene expression, while integrating molecular and physiological indicators with field traits, including grain yield and harvest index, to identify more precise selection markers for wheat improvement programs.
The dissertation was scientifically evaluated by the following examination committee:
Prof. Dr. Abbas Ali Hussein – Chair.
Prof. Dr. Muzaaz Aziz Hussein – Member.
Asst. Prof. Dr. Areej Abdul-Sattar Farman – Member.
Asst. Prof. Dr. Israa Kareem Nasrallah – Member.
Asst. Prof. Dr. Radhia Ali Hassan – Member.
Asst. Prof. Dr. Asaad Kadhim Abdullah – Member and Supervisor.
The study has significant scientific and practical relevance in supporting sustainable agricultural production, improving nutrient-use efficiency, and enhancing cereal-crop productivity under environmental stress conditions. In this context, the research contributes to several United Nations Sustainable Development Goals (SDGs), particularly:
SDG 2 – Zero Hunger: by contributing to improved wheat productivity and mineral-nutrient efficiency, thereby supporting the sustainable production of a major staple cereal crop.
SDG 3 – Good Health and Well-being: through its indirect contribution to sustainable agricultural production and food security.
SDG 12 – Responsible Consumption and Production: by promoting more efficient utilization of essential plant nutrients and agricultural resources.
SDG 13 – Climate Action: by advancing scientific understanding of crop adaptation to environmental stress, thereby supporting more resilient agricultural systems.
