Cadmium stress antioxidant responses and root-to-shoot communication in grafted tomato plants

• Published in: Biometals 2015-10, Vol.28 (5), p.803-816
• Main Authors: Gratão, Priscila Lupino, Monteiro, Carolina Cristina, Tezotto, Tiago, Carvalho, Rogério Falleiros, Alves, Letícia Rodrigues, Peters, Leila Priscila, Azevedo, Ricardo Antunes
• Format: Article
• Language: English
• Subjects: Antioxidants; Antioxidants - metabolism; Ascorbate Peroxidases - metabolism; Biochemistry; Biomedical and Life Sciences; Cadmium; Cadmium - toxicity; Catalase - metabolism; Cell Biology; Detoxification; Glutathione Reductase - metabolism; Grafting; Heavy metals; Hydrogen peroxide; Hydrogen Peroxide - metabolism; Life Sciences; Lipid Peroxidation - drug effects; Lycopersicon esculentum - drug effects; Lycopersicon esculentum - genetics; Lycopersicon esculentum - growth & development; Medicine/Public Health; Metabolic Detoxication, Phase I - genetics; Microbiology; Modulation; Oxidative stress; Oxidative Stress - drug effects; Peroxidase; Peroxidation; Pharmacology/Toxicology; Plant Leaves - drug effects; Plant Leaves - metabolism; Plant pathology; Plant Physiology; Plant Roots - drug effects; Plant Roots - metabolism; Plant Shoots - drug effects; Plant Shoots - metabolism; Plants (organisms); Proline; Stresses; Superoxide Dismutase - metabolism; Tomatoes
• ISSN: 0966-0844; 1572-8773
• DOI: 10.1007/s10534-015-9867-3

Many aspects related to ROS modulation of signaling networks and biological processes that control stress responses still remain unanswered. For this purpose, the grafting technique may be a powerful tool to investigate stress signaling and specific responses between plant organs during stress. In order to gain new insights on the modulation of antioxidant stress responses mechanisms, gas-exchange measurements, lipid peroxidation, H 2 O 2 content, proline, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), ascorbate peroxidase (APX) and guaiacol peroxidase (GPOX) were analyzed in Micro-Tom grafted plants submitted to cadmium (Cd). The results observed revealed that higher amounts of Cd accumulated mainly in the roots and rootstocks when compared to leaves and scions. Macronutrients uptake (Ca, S, P and Mg) decreased in non-grafted plants, but differed among plant parts in all grafted plants. The results showed that the accumulation of proline observed in scions of grafted plants could be associated to the lower MDA contents in the scions of grafted plants. In the presence of Cd, non-grafted plants displayed increased CAT, GR, GPOX and APX activities for both tissues, whilst grafted plants revealed distinct trends that clearly indicate signaling responses from the rootstocks, allowing sufficient time to activate defense mechanisms in shoot. The information available concerning plants subjected to grafting can provide a better understanding of the mechanisms of Cd detoxification involving root-to-shoot signaling, opening new possibilities on strategies which can be used to manipulate heavy metal tolerance, since antioxidant systems are directly involved in such mechanism.