Salvia Miltiorrhiza-Derived Carbon Dots as Scavengers of Reactive Oxygen Species for Reducing Oxidative Damage of Plants

Abstract

Effective removal of excess reactive oxygen species (ROS) from plants is important to minimize biotic and abiotic stress and increase crop yield. Efficient natural ROS scavenging enzymes already exist; however, these enzymes are sensitive to environmental conditions, and it is challenging to produce them on a large scale. In this study, using biomass Salvia miltiorrhiza as the precursor, fluorescence carbon dots (CDs) were synthesized on a large scale using a one-step hydrothermal method. After a series of structural changes, the surface of CDs contains a S. miltiorrhiza-like polymer, which endows the CDs with high antioxidant capacity. These CDs have multiple enzyme activities with stronger antioxidant activity than that of the pure S. miltiorrhiza extract. CDs can scavenge DPPH•, O2 •–, and •OH with excellent scavenging efficiencies of 88.9, 95.6, and 71.4%, respectively. Additionally, the corresponding enzyme activities are superior to those of the natural antioxidant Vc. The synthesized CDs not only have a good scavenging effect on intracellular ROS in plants but can also effectively alleviate the oxidative damage of Italian lettuce under salt stress. Compared with the control group, the root and leaf biomass of Italian lettuce significantly increased by 52.2 and 58.1%, respectively, the water content increased by 48.2%, and malondialdehyde (MDA) content decreased by 92.2%. This study provides a promising strategy for engineering biological antioxidant systems with multiple enzyme activities to attenuate plant biotic stress and abiotic stress.

The role of fluorescent carbon dots in crops: Mechanism and applications

“…97,104 CDs with antioxidant properties have been reported to improve the stress resistance of crops. 97,99,[101][102][103][104][105][106][107][108][109] More applications for CDs in the preharvest process of crops remain to be developed. (3) The molecular mechanism of CDs promoting crop growth remains to be elucidated.…”

“…CDs prepared with PEI as a precursor have been reported to deliver targeted disease resistance genes or biomolecules in crops 97,104 . CDs with antioxidant properties have been reported to improve the stress resistance of crops 97,99,101–109 . More applications for CDs in the preharvest process of crops remain to be developed. The molecular mechanism of CDs promoting crop growth remains to be elucidated.…”

“…While studying the effects of CDs on crop growth, the cytotoxicity of CDs was explored, and the results showed low or no toxicity. 49,51,[97][98][99][100] Studies have shown that CDs can be degraded into plant hormone analogs after they were applied to plants, thus promoting plant growth. 36,37,101 However, the potential effects have been considered to be concentration-dependent, that is, low dose has a promoting effect and high dose has an inhibiting effect.…”

“…The phytotoxicity of CDs has not been fully and definitively described. While studying the effects of CDs on crop growth, the cytotoxicity of CDs was explored, and the results showed low or no toxicity 49,51,97–100 . Studies have shown that CDs can be degraded into plant hormone analogs after they were applied to plants, thus promoting plant growth 36,37,101 .…”

A Strategic Review on Carbon Quantum Dots for Cancer-Diagnostics and Treatment

“…Apart from these unique properties, the presence of multifunctional groups and heteroatoms and large abundance offer more capabilities in the biomedical field. Plenty of precursors are available in nature for the synthesis of CQDs, low molecular weight biomolecules, biopolymers, biomass such as plant leaves ( Shukla et al, 2020 ) ( Li et al, 2021 ), fruits ( Ramezani, Qorbanpour, and Rahbar 2018 ) ( Tadesse et al, 2020 ), vegetables ( Sachdev and Gopinath 2015 ), flowers ( Wang Y. et al, 2020 ; Rojas-valencia et al, 2021 ) and milk ( Han et al, 2015 ; Wang D. et al, 2016 ). In this review, we discuss recent advances of CQDs derived from biomolecules and medicinal plants for their application in oncology research and treatment, including diagnosis of the tumor, cell imaging, photoinduced therapy and drug delivery ( Figure 1 ).…”