The Importance of Different Species of Aspergillus for Stimulation of Plant Growth

Recently, the application of filamentous fungi which can improve the growth of different plants has been considered as an important alternative to the application of synthetic fertilizer in modern sustainable agricultural practices. Plant growth-promoting fungi (PGPF) are fungus residents in the rhizosphere which are beneficial to plants, and the association between these fungi and plants can improve plant growth. Species of Aspergillus have been used in the promotion of plant growth of many agricultural and horticultural plants. The plant growth promotion activity of Aspergillus species can induce better absorption of mineral nutrients through deep root penetration, maintenance of soil pH, and production of siderophores; improved physicochemical processes through delayed senescence, increased photosynthesis, improved stomatal conductance, and improved water-holding capacity; enhanced morphological growth via regulation of phytohormone levels; better reproductive potential and yield through improved physiological and physical growth; higher abiotic stress tolerance through upregulation of stress-ameliorative genes; and better induction of disease resistance. Sustainability is the main driving force for the application and the investigation of biocontrol with plant growth-promoting fungi. The present review article aims to present the most up-to-date results and findings regarding the practical applications of Aspergillus spp. in agricultural and horticultural species. Moreover, the mechanisms of action of these species of fungi are briefly described.