Arbuscular Mycorrhiza Inoculum to Support Sustainable Cropping Systems

Abstract

Arbuscular mycorrhizae (AM) are symbiotic associations, formed between plants and soil fungi that play an essential role in plant growth, plant protection, and soil quality. The AM fungi expand their filaments in soil and plant roots. This filamentous network promote bi‐directional nutrient movement where soil nutrients and water move to the plant and plant photosynthates flow to the fungal network. AM fungi are ubiquitous in the soil and can form symbiosis with most terrestrial plants including major crops, cereals, vegetables, and horticultural plants. In agriculture, several factors, such as host crop dependency to mycorrhizal colonization, tillage system, fertilizer application, and mycorrhizal fungi inoculum's potential can affect plant response and plant benefits from mycorrhizae. Due to their obligate symbiotic status, AM fungi need to associate with plant for growth and proliferation. Consequently, the cultivation of AM fungal strains and the maintenance of reference collections require methodologies and infrastructures quite different from those used with other microbial collections and inoculum production. Interest in AM fungi propagation for agriculture is increasing due to their role in the promotion of plant health, in soil nutrition improvement, and soil aggregate stability. The comprehensive life cycle of AM fungi and methods currently used for the propagation of inoculum and the maintenance of in vivo and in vitro source collections are described. Methods and regulations of large‐scale production of commercial inoculum that provide users with products of high quality and efficiency are discussed.