Nitric oxide mitigates salt-induced oxidative stress in Brassica juncea seedlings by regulating ROS metabolism and antioxidant defense system

Abstract

The present investigation was designed to determine the interaction of nitric oxide with other antioxidants in relieving oxidative stress induced by NaCl at morphological, physiological and molecular level. 15 days old seedlings of B. juncea were subjected to 50 mM NaCl alone, 100 μM SNP alone and in combination (SNP + NaCl) in hoagland growth medium for 96 h and to analyze the cellular homeostasis and salt tolerance mechanism via examining growth, stress parameters, enzymatic and non enzymatic antioxidants and expression level of NR. Exposure of 100 μM sodium nitroprusside to mustard seedling enhanced photosynthetic pigment content and prevented plant growth inhibition. Accumulation of MDA and H 2 O 2 was more pronounced in individual NaCl treated seedling than in the combination of NaCl and SNP. Applying SNP enhanced NR activity by 1.70 folds and increased NO production by 2.26 folds than individual salt treated roots. Furthermore, the activities of CAT, GPX and NR act synergistically with endogenous NO level whereas APX work antagonistically. In addition, the study also demonstrates that NO regulated NaCl induced transcriptional expression of NR. Induction of BjNR in Indian mustard roots lead to enhanced the plant resistance against salinity stress. The present finding revealed that NO confers increased B. juncea tolerance to salt stress by stimulation of antioxidants and reestablishment of cellular redox status.

Exogenous nitric oxide promotes salinity tolerance in plants: A meta-analysis

“…Both one time and regular interval treatments of exogenous NO were efficient for the significant shoot and root dry biomass production in the presence of salinity ( Figures 4C , 5C ). These findings are in agreement with the results on maize ( Kaya et al., 2015 ), chickpea ( Ahmad et al., 2016 ), broccoli ( Brassica oleracea ) ( Akram et al., 2020 ), and chicory ( Cichorium intybus ) ( Abedi et al., 2021 ) in the case of the regular interval, while in maize ( Keyster et al., 2012 ), cotton ( Liu et al., 2013a ), and mustard ( Brassica Juncea ) ( Khator and Shekhawat, 2020 ) for the one-time treatment. However, “continuous” NO treatment limited shoot and root growth under salinity ( Figures 4C , 5C ), suggesting that a continuous supply of exogenous NO could be toxic to plants instead of providing cellular antioxidant protection.…”

Role of Sodium Nitroprusside on Potential Mitigation of Salt Stress in Centaury (Centaurium erythraea Rafn) Shoots Grown In Vitro

“…This reduction may be responsible for the induction of antioxidant defense system to scavenge H 2 O 2 . These results are in accordance with SNP application reducing the H 2 O 2 content in cucumber, lettuce, wheat, brown mustard and lentil [ 23 , 28 , 29 , 66 , 67 ].…”

“…In this work, decreased activities of SOD, CAT and POX were observed in centaury shoots grown under stress conditions caused by NaCl. Although unexpected, the same results were also reported in halophytic species Salvadora persica , date palm and the oil-seed crop Brassica juncea [ 60 , 61 , 67 ]. The positive effect of SNP on the activity of SOD, CAT and POX was previously confirmed in citrus seedlings, wheat and lentil under salinity stress [ 28 , 29 , 85 ].…”

Nitric oxide in plants: an insight on redox activity and responses toward abiotic stress signaling

“…In plant cells, the level of S -nitrosoglutathione (GSNO) is regulated by S - nitrosoglutathione reductase 1 (GSNOR 1). 33 . This enzyme is mainly localized in the cytosol and produces S -nitrosoglutathione (GSNO), an oxidized form of glutathione (GSSG) and ammonia (NH 3 ) by the catalytic reduction of S-nitrosoglutathione (GSNO) using NADH as the reducing equivalent.…”