Enhanced growth in nursery of coffee seedlings inoculated with the rhizosphere fungus Aspergillus niger for field transplantation

Multifunctional microorganisms, showing multiple mechanisms of plant growth promotion, are desirable in the development of microbial formulations. Aspergillus niger is known for its capacity to solubilize mineral phosphates, being considered a promising candidate for the development of inoculants. Furthermore, A. niger can produce phytohormones, which places it as a potential multifunctional plant-growth promoter. To test this potential, we evaluated if A. niger can promote the growth of coffee (Coffea arabica L.) seedlings in a substrate with no P limitation. The seedlings inoculated with a granular formulation of A. niger presented significant increments in height (5.6%), stem diameter (6.1%), number of leaves (8.5%), and mot dry mass (13%) and volume (15%) after 30 weeks. These findings show that A. niger can promote the growth of coffee seedlings in a substrate with no P limitation, providing evidence that A. niger has additional plant growth-promotion traits.