Molybdenum in Plant Biology: From Cofactor Biochemistry to Molybdenum Homeostasis and Stress Adaptation in Crops

Molybdenum (Mo) is an essential micronutrient in plants, where it is incorporated into the molybdenum cofactor (Moco) required for the activity of enzymes central to nitrogen, sulfur, and carbon metabolism. Although plants require Mo only in minute amounts, its availability strongly influences nitrate assimilation, hormone biosynthesis, redox balance, and developmental vigor. Recent advances have clarified key aspects of molybdenum cofactor biosynthesis, enzyme maturation, Mo transport, and intracellular allocation. This also includes symbiotic nitrogen-fixing plants with their bacterial FeMoco synthesis. However, major questions remain regarding how plants coordinate Mo uptake and distribution with developmental demands, nutrient balance, and environmental stress. The relationships between Mo homeostasis, nitrogen-use efficiency, and resilience to abiotic stresses such as drought, salinity, and temperature extremes also require further elucidation as well the study of the interplay between bacterial and plant Mo homeostasis in nitrogen-fixers. Integrative studies connecting cofactor biochemistry with whole-plant physiology and stress responses are therefore needed to advance our understanding of Mo function in crops and model systems.This Research Topic aims to examine the molecular, biochemical, and physiological roles of Mo in plants, with an emphasis on connecting cofactor biochemistry and molybdenum homeostasis with abiotic stress adaptation in crops. It will address how Mo cofactors are synthesized and assembled, the functions of established and emerging plant molybdoenzymes (including the mitochondrial amidoxime reducing component, mARC), and the regulatory networks governing Mo uptake, transport, and homeostasis. Particular attention will be given to the mechanisms through which Mo nutrition shapes nitrogen assimilation, redox balance, and abiotic stress resilience, as well as strategies to optimize Mo-use efficiency in model systems and crops including symbiotic nitrogen-fixers. To maintain a coherent physiological focus and avoid generic agronomic studies, submissions addressing nutrient interactions, bioavailability, or application practices must have a clear, direct mechanistic link to molybdenum metabolism.To gather new insights across molecular biochemistry, cellular transport, and plant physiology, we welcome Original Research, Reviews, and Mini-Reviews addressing, but not limited to, the following themes:-Molybdenum cofactor (Moco) biosynthesis, maturation, and protein–protein interaction networks-Structure, regulation, and catalytic mechanisms of plant molybdoenzymes, including the emerging roles of plant mARC-Mo transporters, uptake kinetics, vascular translocation, and subcellular compartmentation-Regulation of Mo homeostasis at the molecular, cellular, and whole-plant levels-Direct links between Mo nutrition, nitrate assimilation, and nitrogen-use efficiency-Contributions of Mo-dependent enzymes to redox regulation, antioxidant defenses, and hormone metabolism-Mo-mediated physiological and molecular responses to abiotic stress (drought, salinity, heat, cold, and heavy metal toxicity)-Plant-available Mo, chemical speciation, and root uptake mechanisms with an explicit focus on Mo acquisition-Genetic and phenotypic variation in Mo accumulation, utilization, and stress tolerance across germplasm-Physiological and genetic strategies for enhancing Mo-use efficiency and targeted biofortification in crops-Quantitative proteomics, structural biology, metabolomics, and gene-editing approaches to investigate Mo biology Topic editors: Ralf R. Mendel, Katrin Fischer-Schrader Source: https://www.frontiersin.org/research-topics/84044/molybdenum-in-plant-biology-from-cofactor-biochemistry-to-molybdenum-homeostasis-and-stress-adaptation-in-crops