Integrative agronomic and genetic approaches to understand iron and copper deficiency responses in soybean (Glycine max (L.) Merr) and Arabidopsis thaliana

Calcareous-alkaline soil-induced iron (Fe) deficiency chlorosis (IDC) impairs crop growth, yield, and nutritional quality. This thesis investigates agronomic and genetic strategies to enhance the productivity and seed nutrient content of soybean (Glycine max (L.) Merr.) and Arabidopsis thaliana under IDC conditions. IDC-tolerant and sensitive soybean cultivars were analyzed, showing that tolerant cultivars responded better to Fe fertilization, increasing seed Fe concentration, protein content, and size, while reducing seed phytate levels. Genetic analysis identified specific genes within quantitative trait loci (QTL) associated with IDC tolerance, and bioinformatic analysis of Arabidopsis orthologs identified a novel transcription factor, GATA12, involved in iron homeostasis in plant roots. Transcriptomic analysis of IDC-tolerant soybean cultivars showed differential expression of key transcription factors and transporters, including UMAMIT28 from the UMAMIT amino acid transporter family, which plays a crucial role in iron and copper homeostasis. Functional characterization of UMAMIT28 in Arabidopsis confirmed its involvement in maintaining Fe and Cu balance. This thesis highlights the importance of combining agronomic and genetic approaches to enhance crop yield, nutritional quality, and resilience under IDC stress, addressing global food security and malnutrition. Additionally, the discovery of GATA12 and UMAMIT28 advances the understanding of transmetal homeostasis in plants.