Zn2+ play an important role in maintaining the normal functioning of living organisms, and excessive or insufficient levels can cause serious health problems. Zn2+ play a vital role in maintaining normal biological functions, and abnormal levels Zn2+ may lead to a range of severe health issues. Therefore, real-time and accurate detection of Zn2+ is critically important. Given the widespread presence of Zn2+ in living organisms and external environments, developing probes suitable for multi-scenario Zn2+ detection is of significant practical value. In this study, a novel probe SSD was synthesized using salicylaldehyde as the precursor, enabling ultra-sensitive Zn2+ detection with a detection limit as low as 9.1 nM. The probe SSD was successfully applied to the detection of Zn2+ in water, soil, and food samples. In addition, an SSD-based Zn2+ smartphone detection platform was developed, which can quickly detect the content of Zn2+ in actual samples. Moreover, due to its excellent optical properties and low toxicity, SSD was able to detect both intracellular and extracellular Zn2+. Most importantly, probe SSD demonstrated the capability to monitor real-time changes in Zn2+ concentrations during cellular oxidative damage, providing valuable insights for research on related physiological diseases.

Rhizoctonia solani is a significant soil-borne pathogenic fungus that poses a significant threat to the economically important agricultural crops. 4-(Diethylamino)salicylaldehyde (DSA) is a secondary metabolite produced by Streptomyces sp. KN37, which has antifungal activity, meanwhile its inhibitory mechanism is still unclear. In this study, we explored the antifungal efficacy of DSA and its potential mechanism of inhibiting R. solani. It was found that DSA exhibited significant antifungal activity against six tested plant pathogenic fungi, with R. solani being the most sensitive (EC50 = 26.904 mu g/mL). Notably, DSA effectively reduced the mycelial mass and inhibited sclerotia germination, demonstrating a good control efficacy of cucumber damping-off disease. Morphological observation showed that DSA significantly disrupted the shape and ultrastructure of the mycelium. Transcriptomic and metabolomic analyses revealed that DSA impacted the integrity of the cell membrane, redox processes, and energy metabolism in R. solani. The results of fluorescence staining, relative conductivity, H2O2 content, and antioxidant enzyme activity showed that the accumulation of ROS in hypha cells after DSA treatment possibly resulted in damage to cell membrane integrity. Furthermore, the reduction in ATP content, along with decreased ATPase and citrate synthase activity, indicates that energy production may be inhibited. Molecular docking analysis further showed that DSA may competitively inhibit citrate synthase, thereby inhibiting cell energy production and ultimately inducing apoptosis. Our study provides new insights into the potential mechanism by which DSA inhibits the mycelial growth of R. solani.