An insight into genetically modified crop-mycorrhizal symbiosis

Abstract

Genetically modified crops (GMCs) are currently widely used in agricultural biotechnology where plants are engineered to express characters that defend them against different abiotic and biotic stresses. Many studies have revealed that GMCs have sequential benefits for the environment, human well-being, and farmers' economic growth, especially in densely populated countries. Several studies revealed that GMCs can significantly affect the soil microorganisms even their symbiosis with plants. Of these, arbuscular mycorrhizal fungi (AMF) are a good example for the widespread symbiotic relationship as they are associated with maximum crop species and provide several benefits in various agroecosystems. The AMF association can show an imperative functional character in the acquisition of nutrients by the crop plants. In this case, the associated response of transgenic crops and soil microorganisms in relation with AMF may be positive, negative, and neutral. Moreover, GMCs may influence AMF either directly and indirectly through modifications in root exudation or through discrepancies in the variety and action of soil microorganisms. Although Bacillus thuringiensis (Bt) corn is extensively cultivated, a limited number of studies have investigated the interaction of altered lines of Bt corn with symbiotic AMF. These studies pointed out that AMF colonization of genetically modified Bt corn lines differs with quantity and kind of engineered traits. Many research studies reported that GMCs do not affect AMF and failed to find any variations between non-Bt and Bt crops. In contrast, some studies reported a substantial decrease in AMF colonization levels. Therefore, we gathered the information available on the influence of GMCs on AMF in this chapter and consider that it will explore interesting insights on mycorrhizal symbioses in the modern agroecosystems.