Journal Article

Role of brassinosteroids in alleviation of phenanthrene– cadmium co-contamination-induced photosynthetic inhibition and oxidative stress in tomato

Choudhary, Sikander Pal, Zhou, Yanhong, Chen, Shuangchen, Ahammed, Golam Jalal, Shi, Kai, Yu, Jingquan, Xia, Xiaojian

2013

Overview

Heavy metal pollution often occurs together with organic contaminants. Brassinosteroids (BRs) induce plant tolerance to several abiotic stresses, including phenanthrene (PHE) and cadmium (Cd) stress. However, the role of BRs in PHE+Cd co-contamination-induced stress amelioration is unknown. Here, the interactive effects of PHE, Cd, and 24-epibrassinolide (EBR; a biologically active BR) were investigated in tomato plants. The application of Cd (100 μM) alone was more phytotoxic than PHE applied alone (100 μM); however, their combined application resulted in slightly improved photosynthetic activity and pigment content compared with Cd alone after a 40 d exposure. Accumulation of reactive oxygen species and membrane lipid peroxidation were induced by PHE and/or Cd; however, the differences in effect were insignificant between Cd and PHE+Cd. The foliar application of EBR (0.1 μM) to PHE- and/or Cd-stressed plants alleviated photosynthetic inhibition and oxidative stress by causing enhancement of the activity of the enzymes and related transcript levels of the antioxidant system, secondary metabolism, and the xenobiotic detoxification system. Additionally, PHE and/or Cd residues were significantly decreased in both the leaves and roots after application of EBR, more specifically in PHE+Cd-stressed plants when treated with EBR, indicating a possible improvement in detoxification of these pollutants. The findings thus suggest a potential interaction of EBR and PHE for Cd stress alleviation. These results advocate a positive role for EBR in reducing pollutant residues for food safety and also strengthening phytoremediation.

• Publisher: Oxford University Press
• Subject: abiotic stress / analysis / Antioxidants / Antioxidants - metabolism / Biodegradation, Environmental / Biodegradation, Environmental - drug effects / Biological and medical sciences / Biomass / brassinosteroids / Brassinosteroids - pharmacology / cadmium / Cadmium - toxicity / Chlorophyll / Chlorophyll - metabolism / drug effects / Environmental Pollution / Environmental Pollution - analysis / enzymes / enzymology / Fluorescence / foliar application / Food industries / food safety / Fundamental and applied biological sciences. Psychology / Gases / Gases - metabolism / Gene Expression Regulation, Plant / Gene Expression Regulation, Plant - drug effects / General aspects / genetics / heavy metals / Hydrogen Peroxide / Hydrogen Peroxide - metabolism / Hygiene and safety / Inactivation, Metabolic / Inactivation, Metabolic - genetics / leaves / lipid peroxidation / Lipid Peroxidation - drug effects / Lycopersicon esculentum / Lycopersicon esculentum - drug effects / Lycopersicon esculentum - enzymology / Lycopersicon esculentum - genetics / Lycopersicon esculentum - physiology / metabolism / oxidative stress / Oxidative Stress - drug effects / pharmacology / phenanthrenes / Phenanthrenes - toxicity / photosynthesis / Photosynthesis - drug effects / physiology / phytoremediation / phytotoxicity / Plant Leaves / Plant Leaves - drug effects / Plant Leaves - enzymology / Plant physiology and development / pollutants / reactive oxygen species / RESEARCH PAPER / roots / Solanum lycopersicum / Steroids, Heterocyclic / Steroids, Heterocyclic - pharmacology / Superoxides / Superoxides - metabolism / tomatoes / toxicity