Trehalose pretreatment induces salt tolerance in rice (Oryza sativa L.) seedlings: oxidative damage and co-induction of antioxidant defense and glyoxalase systems

Abstract

Salinity in the form of abiotic stress adversely effects plant growth, development, and productivity. Various osmoprotectants are involved in regulating plant responses to salinity; however, the precise role of trehalose (Tre) in this process remains to be further elucidated. The present study investigated the regulatory role of Tre in alleviating salt-induced oxidative stress in hydroponically grown rice seedlings. Salt stress (150 and 250 mM NaCl) for 72 h resulted in toxicity symptoms such as stunted growth, severe yellowing, and leaf rolling, particularly at 250 mM NaCl. Histochemical observation of reactive oxygen species (ROS; O2 (∙-) and H2O2) indicated evident oxidative stress in salt-stressed seedlings. In these seedlings, the levels of lipoxygenase (LOX) activity, malondialdehyde (MDA), H2O2, and proline (Pro) increased significantly whereas total chlorophyll (Chl) and relative water content (RWC) decreased. Salt stress caused an imbalance in non-enzymatic antioxidants, i.e., ascorbic acid (AsA) content, AsA/DHA ratio, and GSH/GSSG ratio decreased but glutathione (GSH) content increased significantly. In contrast, Tre pretreatment (10 mM, 48 h) significantly addressed salt-induced toxicity symptoms and dramatically depressed LOX activity, ROS, MDA, and Pro accumulation whereas AsA, GSH, RWC, Chl contents, and redox status improved considerably. Salt stress stimulated the activities of SOD, GPX, APX, MDHAR, DHAR, and GR but decreased the activities of CAT and GST. However, Tre-pretreated salt-stressed seedlings counteracted SOD and MDHAR activities, elevated CAT and GST activities, further enhanced APX and DHAR activities, and maintained GPX and GR activities similar to the seedlings stressed with salt alone. In addition, Tre pretreatment enhanced the activities of methylglyoxal detoxifying enzymes (Gly I and Gly II) more efficiently in salt-stressed seedlings. Our results suggest a role for Tre in protecting against salt-induced oxidative damage attributed to reduced ROS accumulation, elevation of non-enzymatic antioxidants, and co-activation of the antioxidative and glyoxalase systems.

Insecticidal Activity of Melaleuca alternifolia Essential Oil and RNA-Seq Analysis of Sitophilus zeamais Transcriptome in Response to Oil Fumigation

“…Thus, it led to the inhibition of the activity of GSTs. Both induction and inhibition of GSTs in response to certain plant secondary metabolites by the enzyme inhibition assay have been reported [60, 61]. However, multiple studies have confirmed that the monoterpene compound showed a distinct enzyme inhibition [62, 63].…”

Bacillus licheniformis SA03 Confers Increased Saline–Alkaline Tolerance in Chrysanthemum Plants by Induction of Abscisic Acid Accumulation

“…The values of MDA and EL were determined according to the method reported by Jiang and Zhang (2001). Moreover, the activities of antioxidant enzymes were assayed according to the methods reported by Mostofa et al (2015).…”

Hydrogen peroxide priming modulates abiotic oxidative stress tolerance: insights from ROS detoxification and scavenging

“…ROS like hydrogen peroxide (H 2 O 2 ), superoxide (${\mathrm{O}}_{\mathrm{2}}^{\mathrm{\cdot -}}$), the hydroxyl radical (OH ⋅ ) and singlet oxygen ( 1 ${\mathrm{O}}_{\mathrm{2}}^{\mathrm{\cdot }}$) are also produced as one of the earliest responses of plant cells to environmental stresses, and these ROS molecules can cause damage to a variety of biological processes (Halliwell, 2006; Gill and Tuteja, 2010; Das and Roychoudhury, 2014). In plants subjected to various abiotic stresses, such as salt, drought, chilling, heat and metal or metalloid stresses, ROS levels can rise significantly, leading to redox imbalance and oxidative stress (Hossain et al, 2010; Hasanuzzaman et al, 2011a,b; Hossain and Fujita, 2013; Mostofa and Fujita, 2013; Das and Roychoudhury, 2014; Mostofa et al, 2014a,b,c; Nahar et al, 2014). High ROS levels can result in extensive damage to proteins, DNA, and lipids, thereby affecting normal cellular functions, which can lead to permanent metabolic dysfunction and plant death (Anjum et al, 2015).…”

“…Recent studies have shown that priming can also modulate abiotic stress tolerance (Filippou et al, 2012; Hossain and Fujita, 2013; Mostofa and Fujita, 2013; Borges et al, 2014; Mostofa et al, 2014a,b,c; Nahar et al, 2014; Wang et al, 2014a). Despite the agronomic and ecological importance of priming, in-depth molecular mechanisms associated with priming in plants are still unknown (Conrath, 2011).…”