Arbuscular mycorrhizal symbiosis and alleviation of salinity stress

Abstract

Several environmental factors adversely affect plant growth and development and final yield performance of a crop. Drought, salinity, nutrient imbalances (including mineral toxicities and deficiencies) and extremes of temperature are among the major environmental constraints to crop productivity worldwide. Development of crop plants with stress tolerance, however, requires, among others, knowledge of the physiological mechanisms and genetic controls of the contributing traits at different plant developmental stages. In the past two decades, biotechnology research has provided considerable insights into the mechanism of biotic stress tolerance in plants at the molecular level. Furthermore, different abiotic stress factors may provoke osmotic stress, oxidative stress and protein denaturation in plants, which lead to similar cellular adaptive responses such as accumulation of compatible solutes, induction of stress proteins, and acceleration of reactive oxygen species scavenging systems. Recently, various methods are adapted to improve plant tolerance to salinity injury through either chemical treatments (plant hormones, minerals, amino acids, quaternary ammonium compounds, polyamines and vitamins) or biofertilizers treatments (Asymbiotic nitrogen-fixing bacteria, symbiotic nitrogen-fixing bacteria) or enhanced a process used naturally by plants (mycorrhiza) to minimise the movement of Na+ to the shoot. Proper management of Arbuscular Mycorrhizal Fungi (AMF) has the potential to improve the profitability and sustainability of salt tolerance. In this review article, the discussion is restricted to the mycorrhizal symbiosis and alleviation of salinity stress.

Salinity Stress and Arbuscular Mycorrhizal Symbiosis in Plants

“…Salinity not only reduces yield of crops but also disrupts the ecological balance of the area (Aggarwal et al 2012). Several literatures have reported that arbuscular mycorrhizal (AM) fungi act as growth regulator and mitigate the harmful effects of plants exposed to salt stress.…”

“…Among the environmental stress, soil salinity globally results in the greater loss in agricultural productivity and therefore affecting the lives of humans and animals (Aggarwal et al 2012). Evelin et al (2009) reported that 50 % loss of cultivated land affected by salinity and also the photosynthesis, protein synthesis, lipid and energy metabolism.…”

Responses of Different Panicum miliaceum L. Genotypes to Saline and Water Stress in a Marginal Mediterranean Environment

“…In Europe, about 3.8 million ha are affected by soil salinization due to natural saline soils in Spain, Hungary, Greece, and Bulgaria, or irrigation with saline water in significant areas of Sicily and the Ebro Valley in Spain and in other smaller parts of Italy, Hungary, Greece, Portugal, France, Slovakia, and Romania [6]. Plants growing in saline soil are subjected to three distinct physiological stresses: (1) toxic effects of specific ions such as sodium and chloride, which disrupt the structure of enzymes and other macromolecules, damage cell organelles, reduce photosynthesis and respiration, inhibit protein synthesis, and induce ion deficiency [7,8]; (2) osmotic effects due to physiological drought because plants must maintain lower internal osmotic potential to prevent water from moving from the roots into the soil [9]; and (3) nutrient imbalances caused by depression in uptake and/or transport [10,11].…”

Association and mycorrhizal dependency in Jatropha curcas L. seedlings under salt stress

“…However, the mycorrhizae did not increase the dry matter in the control treatment plants. Arbuscular mycorrhizal fungi promote a better absorption of nutrients, compartmentalization of toxic ions, and production of osmolytes that mitigate the effects of salinity (Aggarwal et al, 2012). Phosphorus is one of the nutrients that have its absorption increased by the presence of AMF in the roots (Saboya et al, 2012).…”

“…The AMF penetrate plant roots and their network of hyphae spreads in the soil, highly increasing the surface area for absorption (Silva et al, 2001;Latef & Miransari, 2014;Bonfante & Desirò, 2015). However, under saline conditions, the difficulty in obtaining water affects the germination of AMF spores and the symbiosis is not always established (Sheng et al, 2008;Aggarwal et al, 2012).…”