Perspectives on the Role of Arbuscular Mycorrhizal Fungi in the In Vivo Vegetative Plant Propagation

Abstract

Vegetative propagation is an important method for increasing the productivity of economically important agricultural and horticultural plants. Apart from the application of phytohormones, beneficial microorganisms such as arbuscular mycorrhizal (AM) fungi being natural biofertilizers are also widely used in the field of horticultural production systems. The mutualistic association between the AM fungi and plant are not only known for their efficient water and nutrient uptake, less vulnerability to pathogens, and ability to withstand or tolerate abiotic and biotic stresses but are also involved in the production of plant hormones and adventitious root formation in asexual propagation. The inoculation of AM fungi to the rooting substrate could result in similar responses on the cuttings to those obtained through the application of exogenous plant growth regulators. In addition, the combined use of AM fungi along with plant hormones leads to increased root initiation and development of plant parts. The early inoculation of AM fungi onto the rooting medium enhances the plant growth rate of vegetatively propagated plant species after forming a symbiotic relationship with the plant. Moreover, a series of sequential signaling events are known to occur between AM fungi and the host plant during the development of roots. The present chapter focuses on the role of AM fungi in various types of vegetative propagation including cutting, layering, and grafting, the interaction between the plant hormones, and the AM symbiosis. The mechanism involved in the production of plant hormones through AM fungi and thereby the physiological changes occurring in the plant metabolism during propagation is also discussed.