Nanobiotechnology-mediated regulation of reactive oxygen species homeostasis under heat and drought stress in plants

Traditionally, reactive oxygen intermediates (ROIs) were considered to be toxic by-products of aerobic metabolism, which were disposed of using antioxidants. However, in recent years, it has become apparent that plants actively produce ROIs as signaling molecules to control processes such as programmed cell death, abiotic stress responses, pathogen defense and systemic signaling. Recent advances including microarray studies and the development of mutants with altered ROI-scavenging mechanisms provide new insights into how the steady-state level of ROIs are controlled in cells. In addition, key steps of the signal transduction pathway that senses ROIs in plants have been identified. These raise several intriguing questions about the relationships between ROI signaling, ROI stress and the production and scavenging of ROIs in the different cellular compartments.

An updated comprehensive review to help researchers understand nanozymes better and in turn to advance the field. Nanozymes are nanomaterials with enzyme-like characteristics ( Chem. Soc. Rev. , 2013, 42 , 6060–6093). They have been developed to address the limitations of natural enzymes and conventional artificial enzymes. Along with the significant advances in nanotechnology, biotechnology, catalysis science, and computational design, great progress has been achieved in the field of nanozymes since the publication of the above-mentioned comprehensive review in 2013. To highlight these achievements, this review first discusses the types of nanozymes and their representative nanomaterials, together with the corresponding catalytic mechanisms whenever available. Then, it summarizes various strategies for modulating the activity and selectivity of nanozymes. After that, the broad applications from biomedical analysis and imaging to theranostics and environmental protection are covered. Finally, the current challenges faced by nanozymes are outlined and the future directions for advancing nanozyme research are suggested. The current review can help researchers know well the current status of nanozymes and may catalyze breakthroughs in this field.

Reactive oxygen species (ROS) are thought to play a dual role in plant biology. They are required for many important signaling reactions, but are also toxic byproducts of aerobic metabolism. Recent studies revealed that ROS are necessary for the progression of several basic biological processes including cellular proliferation and differentiation. Moreover, cell death-that was previously thought to be the outcome of ROS directly killing cells by oxidation, in other words via oxidative stress-is now considered to be the result of ROS triggering a physiological or programmed pathway for cell death. This Opinion focuses on the possibility that ROS are beneficial to plants, supporting cellular proliferation, physiological function, and viability, and that maintaining a basal level of ROS in cells is essential for life.