Nitric oxide could allay arsenic phytotoxicity in tomato (Solanum lycopersicum L.) by modulating photosynthetic pigments, phytochelatin metabolism, molecular redox status and arsenic sequestration

Abazar Ghorbani,Leila Pishkar,Nasim Roodbari,Necla Pehlivan,Chu Wu

doi:10.1016/j.plaphy.2021.08.019

Abstract

Plants do not always have the genetic capacity to tolerate high levels of arsenic (As), which may not only arrest their growth but pose potential health risks through dietary bioaccumulation. Meanwhile, the interplay between the tomato plants and As–NO-driven molecular cell dynamics is obscure. Accordingly, seedlings were treated with As (10 mg/L) alone or in combination with 100 μM sodium nitroprusside (SNP, NO donor) and 200 μM 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO, NO scavenger). Sodium nitroprusside immobilized As in the roots and reduced the shoot translocation by up-regulating the transcriptional expression of the PCS, GSH1, MT2, and ABC1. SNP further restored the growth retardation through modulating the chlorophyll and proline metabolism, increasing NO accumulation and stomatal conductance along with clear crosstalk between the antioxidant activity as well as glyoxalase I and II leading to endogenous H2O2 and MG reduction. Higher PCs and glutathione accumulation helped protect photosynthetic apparatus; however, cPTIO reversed the protective effects of SNP, confirming the role of NO in the As toxicity alleviation.

Highlights

Today, anthropogenic activities, including irrigation of crops with contaminated groundwater and uncontrolled use of herbicides and pesticides, have led to increased arsenic (As) pollution in waters, sediments and soils
Higher PCs and glutathione accumulation helped to protect photosynthetic apparatus, cPTIO reversed the protective effects of sodium nitroprusside (SNP), authenticating the role of NO in the As toxicity alleviation
Tomato seedling heights were found to be declined by 23.3%, 25.4% and 22.8% with As, As + cPTIO and As + SNP + cPTIO treatments, respectively, compared to the untreated controls

Summary

Introduction

Anthropogenic activities, including irrigation of crops with contaminated groundwater and uncontrolled use of herbicides and pesticides, have led to increased arsenic (As) pollution in waters, sediments and soils. This has resulted a sharp risk for plants. Yadav [68] indicated that the toxic As levels generates oxidative stress in plants by damaging the photosynthetic apparatus itself, by disrupting the electron transfer chains and the redox balance. A strong defense system consisting glyoxalase system and the antioxidant systems can effectively increase plant tolerance to external abiotic stresses such as arsenic toxicity. Seedlings were treated with As (10 mg/L) alone or in combination with 100 μM sodium nitroprusside (SNP, NO donor) and 200 μM 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3oxide (cPTIO, NO scavenger)

Methods

Results

Discussion

Conclusion