Naringenin- and Funneliformis mosseae-Mediated Alterations in Redox State Synchronize Antioxidant Network to Alleviate Oxidative Stress in Cicer arietinum L. Genotypes Under Salt Stress

Abstract

Salinity causes multifarious adverse effects in plants and one of its inevitable consequences is overproduction of reactive oxygen species (ROS). Arbuscular mycorrhizal (AM) symbiosis helps plants to thrive in saline soils by countering stress-induced oxidative damage, and flavonoids have been reported to improve plant redox status. However, little is known about the influence of flavonoids and/or AM in transforming the competence of the entire antioxidant machinery in salt-stressed plants. The present study was conducted to evaluate the potential role of naringenin (Nar) and mycorrhiza (Funneliformis mosseae) in modulating the antioxidant network to mitigate salinity-induced oxidative stress of two Cicer arietinum L. genotypes (PBG 5 and DCP 92-3). Despite the increase in enzymatic and non-enzymatic antioxidants under salt stress, ROS buildup increased, more in DCP 92-3 than PBG 5. Under salt stress, the increasing oxidative burden was coupled with lowering of ascorbate/dehydroascorbate and reduced/oxidized glutathione levels indicating that for efficient antioxidation, maintaining redox buffers may be of pivotal importance. However, in Nar-treated and/or AM plants, increased antioxidants efficiently attenuated oxidative loads, with the greatest redox stability attained by +Nar +AM plants. Improved efficacy was related to elevated recycling of reduced glutathione and ascorbate, thereby facilitating higher activity of scavenging antioxidants. However, PBG 5 was more responsive to Nar treatment and/or AM inoculation and displayed better redox equilibrium than DCP 92-3. The study suggested that to impart salinity tolerance to chickpea, besides improving nodulation, mitigation of oxidative burden by shifting the redox system toward a more reduced form is another important protective mechanism adopted by Nar and F. mosseae.