Improving Activity of Native Arbuscular Mycorrhizal Fungi (AMF) for Mycorrhizal Benefits in Agriculture: Status and Prospect

Agricultural importance and ecological implications of arbuscular mycorrhizal (AM) symbiosis with land plants are well known. AM symbiosis facilitates plant growth through enhancing uptake of several macro- and micro-nutrients of low mobility in soil, like phosphorus, zinc, copper etc. Beside nutritional benefits to plant, AM also contributes to numerous ecological advantages like influencing microbial and chemical environment of the mycorrhizosphere, stabilizing soil aggregates, conferring tolerance (plant) to several abiotic and biotic stresses, bioremediation of soil and supplying protective (antioxidants) nutrient components to human being through agricultural products (food). There are two approaches to exploit arbuscular mycorrhiza for crops: (1) soil introduction of non-native inoculum and (2) exploitation of native AM fungal (AMF) population. The approach of soil introduction of non-native inoculum of selected AMF to field crops suffers from (i) cost intensiveness, (ii) inconsistent competitive performance of introduced inoculum due to lack of adaptability to new ecology and (iii) negative ecological consequences in terms of possible introduction of invasive species as unintended contaminants. Exploitation of native AM fungal (AMF) population of soils, keeping it undisturbed by avoiding faulty agricultural practices, is an alternative approach, now promoted for sound ecological management of crop production, particularly under stressful situations. The approach is based on twin attributes of AM symbiosis – ubiquitous nature and lack of host specificity of AMF. Several prospective avenues of enhancing native AM activities through agronomic manipulations of crop management practices and cropping systems for enhanced response to diverse native AMF population have been discussed in the present article