Proline-2'-deoxymugineic acid (PDMA) increases seed quality and yield by alleviating iron deficiency symptoms in soybean under calcareous-alkaline conditions

Iron (Fe) deficiency in crops, particularly in calcareous-alkaline soils, poses a major challenge due to Fe immobilization. While synthetic chelators like EDTA and EDDHA are commonly used to improve Fe availability, proline-2-deoxymugineic acid (PDMA) has emerged as a promising alternative, enhancing Fe nutrition in crops such as rice and cucumber. This study aimed to assess the effectiveness of PDMA on soybean growth and yield under calcareous-alkaline conditions. A pot trial demonstrated that PDMA improves Fe uptake, translocation, and storage in soybeans, leading to increased chlorophyll content, and enhanced root and shoot growth. Even at low dosages, PDMA significantly improved plant development, with the highest dosage (30 M) resulting in notable increases in Fe, Zn, Mn, and Mg concentrations in roots, leaves, and seeds, surpassing the effects of the synthetic chelator Fe-EDDHA in several parameters. Additionally, 30 M PDMA substantially boosted soybean yield, increasing pod and seed number, and 100-seed weight. It also improved seed quality by increasing protein and oil content. These findings suggest that PDMA offers a sustainable, effective alternative to traditional Fe chelators, providing a viable solution for addressing Fe deficiency and enhancing crop biofortification in challenging soil conditions.