Arbuscular Mycorrhiza-Mediated Alterations in Redox Buffer Synchronize Antioxidant Network to Alleviate Salt Induced Oxidative Burden in Host Legumes and their Nodules : A Review

Neera Garg, Priyanka Singla

Abstract


Legumes represent an important resource-conserving component of sustainable
agricultural system as they fix atmospheric nitrogen and thus reduce the need for
chemical fertilizers while enhancing overall crop productivity. However, most legumes
are salt-sensitive, where adverse effects of salinity are referred through its detrimental
effects on nitrogen fixing symbiosis in the nodules. High rates of respiration and the
presence of O -sensitive metalloproteins and leghemoglobin in the nodules, particularly 2
favor Reactive Oxygen Species (ROS) overproduction and thus makes nodule highly salt
susceptible. Despite destructive activity of ROS, they are well-described second
messengers in a variety of cellular processes, including nodule development and
functioning. Under steady state conditions, antioxidative system comprising of the
nonenzymic as well as enzymic antioxidants work in concert to control the cascades of
uncontrolled oxidation and this redox balance orchestrates various metabolic activities,
including nodulation process. However, salinity induced disturbance in cellular
homeostasis eventually perturbs equilibrium between production and scavenging of
ROS, thereby grounding progressive oxidative damage to proteins, DNA and lipids of both
symbionts and thus induce nodular premature senescence and ultimately reduce legume
productivity. Efficient antioxidative activity does not necessarily mean strong
upregulation of full set of antioxidants, indeed redox balance as a result of
synchronization between protective and regeneration antioxidant systems plays a
crucial role in the regulation of nodule functioning and determines salt tolerance in most
legumes. Apart from the intrinsic protective systems of legumes against stress,
exploitation of arbuscular mycorrhizal fungi, another microorganism hosted by legumes,
opens new alternatives for a pyramiding strategy against salinity induced oxidative
damage. In the current review, we provide an inclusive update on the salt-induced
oxidative burden in legumes, especially their nodules and recent advances on the
emerging role of arbuscular mycorrhiza (AM) in imparting salt tolerance by altering
redox buffers through fine regulation of ascorbate-glutatione (AsA-GSH) cycle.

Keywords


Antioxidants, Antioxidative activity, Arbuscular mycorrhizal, AsA-GSH cycle, Ascorbate-glutatione, Glycolate oxidase, Legumes, Oxidative stress, RuBisCO Salinity

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DOI: https://doi.org/10.18811/ijpen.v2i1-2.6617

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