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

Abstract

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, H2O2 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.

Role of Acinetobacter sp. CS9 in Improving Growth and Phytoremediation Potential of Catharanthus longifolius under Cadmium Stress

“…The increased activity of antioxidant enzymes may reduce the production of ROS in plants under stress. The current study revealed increased levels of CAT and SOD in plants under Cd stress [45]. The activity of these enzymes was further increased in inoculated plants under Cd stress.…”

Photosynthesis is differently regulated during and after copper‐induced nutritional stress in citrus trees

“…Similar to citrus trees, increased activities of SOD followed by APX in sugarcane were important to prevent damages to the photosynthetic machinery of plants under drought stress (Sales et al ). This emphasizes the importance of understanding the balance between activities of APX and CAT enzymes, and possibly other peroxidases not analyzed in this study, which generally have a different role in the elimination of H 2 O 2 (Gratão et al , Anjum et al , Hippler et al ).…”

Root-to-Shoot Communication to Modulate Source-Sink Relationship in Tomato Depends on Phytochromes

“…To better understand the factors involved in root-to-shoot signaling, grafting has been an important research tool because molecular and/or biochemical changes, either endogenously or exogenously induced, in the scion can result from modifications in both the root and shoot (Gratão et al, 2015, Gaion et al, 2018. Thus, to study light signaling, especially that phytochrome-dependent, in photoassimilate partition control, it is interesting to associate the grafting technique with molecular tools, such as photomorphogenic mutants.…”