ARBUSCULAR MYCORRHIZAL FUNGI IN THE ALLEVIATION OF OXIDATIVE STRESS UNDER CUTTING PROPAGATION MANAGEMENT

BOMPADRE MJ; COLOMBO R; GODEAS ALICIA; A. PARDO

Mycorrhizas: structure, development and functions

Nova Publishers

Año: 2014; p. 181 - 202

Abstract   The capacity of roots to sense soil physicochemical parameters plays an essential role in maintaining plant nutritional and developmental functions under abiotic stress. Drought greatly affects the growth and development of plants and can cause extensive losses to agricultural productivity. The water regime affects a wide variety of physiological and biochemical processes in plants including an increased production of reactive oxygen species (ROS) capable of causing oxidative damage to proteins, DNA and lipids. Moreover, this ROS production can induce cellular, anatomical, and morphological changes that improve drought tolerance. Arbuscular mycorrhizal fungi (AMF) colonize a wide range of plant species though the ability of different AMF to promote host growth and/or water deficit resistance is variable. AMF contributes to drought tolerance through a combination of physical, nutritional and physiological effects. The response to oxidative stress depends on many factors, including the organism tissue and the degree of stress. In most cases mycorrhizal plants increase antioxidant defenses, such as the ROS-scavenging enzymes superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX). AMF can maintain the levels of malondialdehyde (MDA), a compound indicative of lipid damage, by rapidly increasing antioxidant defenses and preventing lipid damage. In other cases an increase of MDA is observed in mycorrhizal plants due to an active response to oxidative stress. A critical step of AMF inoculation technology is the appropriate selection of fungal isolates to be used as inoculants. Nursery cultivation is the most convenient way to improve the success of semi-woody cuttings transplantation (e.g. olive, pomegranate, citrus) at the crop area. Plants suffer at least two transplant moments in nursery conditions prior to outside cultivation. AMF can reduce transplant stress by changing the morphology of the root system favouring the establishment of plants. Thus AMF can greatly contribute to crop productivity and environmental sustainability. Artificial inoculation of plant cuttings with AMF at an early stage of cutting development has been adopted by an increasing number of nursery managers as a method for promoting growth, production and precocity. Moreover, it is an essential component for most plants and it can be used as a biofertilizer resource. In this chapter we discuss the effect of an early AMF inoculation in alleviating oxidative stress in semi-woody cutting propagation management under nursery conditions. We also discuss the benefits of AMF to solve the problematic issue of water deficit and transplant stresses generated during plant growth.