Nitrate reductase is required for salicylic acid‐induced water stress tolerance of pepper by upraising the AsA‐GSH pathway and glyoxalase system

Abstract

A trial was conducted to evaluate whether nitrate reductase (NR) participates in salicylic acid (SA)-improved water stress (WS) tolerance in pepper (Capsicum annuum L.) plants. Before starting WS treatment, 0.5 mM SA was applied to half of the well-watered (WW) plants as well as to WS-plants as a foliar spray once a day for a week. The soil water holding capacity was maintained at 40 and 80% of the full water storing capacity for WS and and well-watered (WW) plants, respectively. Water stress caused substantial decreases in total plant dry weight, F v /F m , chlorophyll a and b, relative water content, leaf water potential (ΨI) by 53, 37, 49, 21, 36 and 33%, respectively relative to control, but significant increases in malondialdehyde (MDA), hydrogen peroxide (H 2 O 2 ), electrolyte leakage (EL), methylglyoxal (MG), proline, key antioxidant enzymes' activities, NO and NR activity. The SA reduced oxidative stress, but improved antioxidant defence system, ascorbate-glutathione (AsA-GSH) cycle enzymes, glyoxalase system-related enzymes, glyoxalase I (Gly I) and glyoxalase II (Gly II), plant growth, photosynthetic traits, NO, NR and proline. SA-induced WS tolerance was further improved by supplementation of sodium nitroprusside (SNP), a donor of NO. NR inhibitor, sodium tungstate (ST) was applied in conjunction with SA and SA + SNP to the WW and WS-plants to assess whether NR contributes to SA-improved WS tolerance. ST abolished the beneficial effects of SA by reducing NO and NR activity in WS-pepper, but the application of SNP along with SA + ST reversed negative effects of ST, showing that NO and NR are jointly needed for SA-induced WS tolerance of pepper plants.

Kuraklık Stresi Altında Sarı Kantaronun (Hypericum perforatum L.) Fizikokimyasal ve Antioksidan Tepkileri

“…4). Similar observations for SOD, CAT, and GR increases were reported for tomato [44], chrysanthemum [45], Oudneya africana [37], wheat [38], soybean [16], and pepper [46] under drought stress. Another antioxidant enzyme measured in this study was POX, which is also responsible for detoxifying H2O2 in chloroplasts and cytosols.…”

γ-Aminobutyrate (GABA) Regulated Plant Defense: Mechanisms and Opportunities

“…It is known that the exogenous application of GABA, ABA and salicylate alleviate the drought-induced damage to membranes and leaf water status in creeping bentgrass by affecting similar metabolic pathways, yet cause differential changes in metabolite accumulation [155]. Additionally, NO and nitrate reductase are jointly needed for salicylate-induced water-stress tolerance in pepper plants [189]. The osmotin protein, which belongs to the PR-5 family of pathogenesisrelated proteins, is known to inhibit the activity of defensive cell wall barriers in fungi [190].…”

Salicylic Acid Increases Photosynthesis of Drought Grown Mustard Plants Effectively with Sufficient-N via Regulation of Ethylene, ABA and Nitrogen-Use Efficiency

“…It also increased NR activity and nitrate assimilation in isolated cucumber cotyledons. Kaya (2020) found that in pepper under drought, nitrate reductase is required for SA-induced drought tolerance through upregulation of ascorbate-glutathione pathway and glyoxylase system. Gunes et al (2007) reported that SA stimulated the concentrations of mineral nutrient such as phosphorus (P), potassium (K), magnesium (Mg), and manganese (Mn) in Zea mays under water de cit and boron stress.…”

“…SA also interacts with N assimilation, affects proline metabolism and photosynthesis (Khan et al2015). Thus, increased SA synthesis under drought stress (Hussain et al 2021;Kaya 2020;Khalvandi et al 2021) might play a role in acclimation of plant through maximum utilization of the available water resources.…”