Chitosan-Induced Activation of the Antioxidant Defense System Counteracts the Adverse Effects of Salinity in Durum Wheat

Abstract

The present study was carried out with the aim of (i) evaluating the effect of chitosan (CTS) on the growth of durum wheat under salinity and (ii) examining CTS-regulated mechanisms of salinity tolerance associated with the antioxidant defense system. To achieve these goals, durum wheat seedlings were treated with CTS at different molecular weight, low (L-CTS, 50–190 kDa), medium (M-CTS, 190–310 kDa) and high (H-CTS, 310–375 kDa). The results obtained show that exposure to 200 mM NaCl reduced the shoot and the root dried biomass by 38% and 59%, respectively. The growth impairment induced by salinity was strongly correlated with an increase in the superoxide anion production (5-fold), hydrogen peroxide content (2-fold) and malondialdehyde (MDA) content (4-fold). Seedlings responded to the oxidative stress triggered by salinity with an increase in the total phenolic content (TPC), total flavonoid content (TFC) and total antioxidant activity (TAA) by 67%, 51% and 32%, respectively. A salt-induced increase in the activity of the antioxidant enzymes superoxide dismutase and catalase (CAT) of 89% and 86%, respectively, was also observed. Treatment of salt-stressed seedlings with exogenous CTS significantly promoted seedling growth, with the strongest effects observed for L-CTS and M-CTS, which increased the shoot biomass of stressed seedlings by 32% and 44%, respectively, whereas the root dried biomass increased by 87% and 64%, respectively. L-CTS and M-CTS treatments also decreased the superoxide anion production (57% and 59%, respectively), the hydrogen peroxide content (35% and 38%, respectively) and the MDA content (48% and 56%, respectively) and increased the TPC (23% and 14%, respectively), the TFC (19% and 10%, respectively), the TAA (up to 10% and 7%, respectively) and the CAT activity (29% and 20%, respectively). Overall, our findings indicate that CTS exerts its protective role against the oxidative damages induced by salinity by enhancing the antioxidant defense system. L-CTS and M-CTS were the most effective in alleviating the adverse effect of NaCl, thus demonstrating that the CTS action is strictly related to its molecular weight.

Use of a Biostimulant to Mitigate Salt Stress in Maize Plants

“…Our experiment showed that the salt stress caused significant increases in TPC in unbiostimulated plants, and this can be seen as a plant response to improve its free radical scavenging activity (Table 3). Therefore, it can be concluded based on TPC results that the biostimulant reduced the stress and, consequently, the TPC in maize [59].…”

Biochar and Chitosan Regulate Antioxidant Defense and Methylglyoxal Detoxification Systems and Enhance Salt Tolerance in Jute (Corchorus olitorius L.)

“…Detoxification of H 2 O 2 by enhancing CAT and POD activity with CHT amendment resulted in increased tolerance of milk thistle plants to salinity [ 65 ]. Foliar application of low- and medium-molecular-weight CHT to durum wheat under salt stress increased the activities of SOD and CAT [ 66 ]. Likewise, SOD, CAT, and POD activities were increased following foliar application of CHT in salt-stressed tomato plants [ 58 ].…”

Chitosan, chitosan nanoparticles and modified chitosan biomaterials, a potential tool to combat salinity stress in plants

“…Cs and CsNPs application improved plant productivity under different stressed conditions by boosting plant immune responses and by the activation of various defense related enzymes and decreasing reactive oxygen species (ROS) of plants (E. F. Ali et al, 2021;Attia et al, 2021;Picchi, Gobbi, Fattizzo, Zefelippo, & Faoro, 2021;Quitadamo, De Simone, Beleggia, & Trono, 2021).…”