Tripartite association among plant, arbuscular mycorrhizal fungi and bacteria

Abstract

Most plant roots are colonized by arbuscular mycorrhizal (AM) fungi and their presence, generally, stimulates plant growth. In addition, AM fungi can interact with different bacterial species establishing a tripartite association and represent a vital component in the plant ecosystem. These interactions may range from loose to endosymbiotic association. In context of AM fungi, interaction with host plant is long been studied, however, information is little on the mechanisms controlling interaction of bacteria with AM fungi and host plant in the mycorrhizosphere. Understanding the interaction between AM fungi and bacteria is essential for describing the soil-plant interface. Although there are several studies concerning interactions between AM fungi and bacteria, the underlying mechanisms behind these associations are in general not very well understood, and their functional properties still require experimental confirmation. Modern tools of molecular biology and genome sequencing have solved the questions about the identity and role of bacteria associated with AM fungi. In this chapter, different aspects of tripartite association among plant, AM fungi and bacteria are discussed with greater emphasis on associated bacterial component.